diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..ca77abb
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,33 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Build
+        run: ./gradlew build
+
+      - name: Upload test reports
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-reports
+          path: build/reports/tests/
diff --git a/.gitignore b/.gitignore
index d671e00..d6421f6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,7 @@
 
 # Package Files #
 *.jar
+!gradle/wrapper/gradle-wrapper.jar
 *.war
 *.ear
 
diff --git a/README.md b/README.md
index 598b516..8dc7e78 100644
--- a/README.md
+++ b/README.md
@@ -79,11 +79,11 @@ For large files, use callbacks to process records without storing them all in me
 
 ```java
 SieDocumentReader reader = new SieDocumentReader();
-reader.streamValues = true;
-reader.callbacks.setVER(voucher -> {
+reader.setStreamValues(true);
+reader.getCallbacks().setVER(voucher -> {
     // Process each voucher as it is parsed
 });
-reader.callbacks.setIB(periodValue -> {
+reader.getCallbacks().setIB(periodValue -> {
     // Process each opening balance entry
 });
 reader.readDocument("large-file.SE");
diff --git a/docs/DEVELOPER.md b/docs/DEVELOPER.md
index 5eb32be..cfe0377 100644
--- a/docs/DEVELOPER.md
+++ b/docs/DEVELOPER.md
@@ -168,7 +168,7 @@ RuntimeException
         ├── SieDateException
         ├── SieMissingMandatoryDateException
         ├── SieMissingObjectException
-        ├── SieVoucherMissmatchException
+        ├── SieVoucherMismatchException
         └── MissingFieldException
 ```
 
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..f8e1ee3
Binary files /dev/null and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/src/main/java/alipsa/sieparser/Encoding.java b/src/main/java/alipsa/sieparser/Encoding.java
index c964a96..9639477 100644
--- a/src/main/java/alipsa/sieparser/Encoding.java
+++ b/src/main/java/alipsa/sieparser/Encoding.java
@@ -25,13 +25,7 @@ of this software and associated documentation files (the "Software"), to deal
 
 package alipsa.sieparser;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import java.nio.charset.Charset;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.List;
 
 /**
  * Handles character encoding for SIE files.
@@ -41,9 +35,7 @@ public class Encoding {
 
     private Encoding() {}
 
-    Logger logger = LoggerFactory.getLogger(Encoding.class);
-
-    private static Charset defaultCharset=Charset.forName("IBM437");
+    private static final Charset defaultCharset = Charset.forName("IBM437");
 
     /**
      * Returns the charset used for SIE file encoding (IBM437).
@@ -55,23 +47,12 @@ public static Charset getCharset() {
     }
 
     /**
-     * Converts a string to a collection of bytes using the SIE charset.
+     * Converts a string to a byte array using the SIE charset.
      *
      * @param value the string to convert
-     * @return a collection of bytes representing the string in IBM437 encoding
+     * @return a byte array representing the string in IBM437 encoding
      */
-    public static Collection<Byte> getBytes(String value) {
-        byte[] byteArray =  value.getBytes(getCharset());
-        List<Byte> byteList = new ArrayList<>();
-        for (byte b : byteArray) {
-            byteList.add(Byte.valueOf(b));
-        }
-        return byteList;
-    }
-
-    /*
-    public byte[] getByteArray(String value) {
+    public static byte[] getBytes(String value) {
         return value.getBytes(getCharset());
     }
-    */
 }
diff --git a/src/main/java/alipsa/sieparser/IoUtil.java b/src/main/java/alipsa/sieparser/IoUtil.java
index 6e2a5cb..b3c2c36 100644
--- a/src/main/java/alipsa/sieparser/IoUtil.java
+++ b/src/main/java/alipsa/sieparser/IoUtil.java
@@ -24,11 +24,7 @@ of this software and associated documentation files (the "Software"), to deal
 package alipsa.sieparser;
 
 import java.io.*;
-import java.nio.charset.CharsetDecoder;
-import java.nio.charset.CharsetEncoder;
-import java.nio.charset.CodingErrorAction;
 import java.nio.file.Files;
-import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardOpenOption;
 
@@ -47,14 +43,7 @@ private IoUtil() {}
      * @throws IOException if the file cannot be opened
      */
     public static BufferedReader getReader(String fileName) throws IOException {
-        /*
-        CharsetDecoder decoder = Encoding.getCharset().newDecoder();
-        decoder.onMalformedInput(CodingErrorAction.REPORT);
-        InputStreamReader isReader = new InputStreamReader(new FileInputStream(fileName), decoder);
-        return new BufferedReader( isReader );
-        */
         return Files.newBufferedReader(Paths.get(fileName), Encoding.getCharset());
-
     }
 
     /**
@@ -66,19 +55,7 @@ public static BufferedReader getReader(String fileName) throws IOException {
      * @throws IOException if the file cannot be opened or created
      */
     public static BufferedWriter getWriter(String fileName) throws IOException {
-        /*
-        CharsetEncoder encoder = Encoding.getCharset().newEncoder();
-        encoder.onUnmappableCharacter(CodingErrorAction.REPORT);
-        OutputStreamWriter osWriter = new OutputStreamWriter(new FileOutputStream(fileName), encoder);
-        return new BufferedWriter( osWriter );
-        */
-        Path filePath = Paths.get(fileName);
-        StandardOpenOption option;
-        if (Files.exists(filePath)) {
-            option = StandardOpenOption.WRITE;
-        } else {
-            option = StandardOpenOption.CREATE_NEW;
-        }
-        return Files.newBufferedWriter(Paths.get(fileName),Encoding.getCharset(), option);
+        return Files.newBufferedWriter(Paths.get(fileName), Encoding.getCharset(),
+                StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING);
     }
 }
diff --git a/src/main/java/alipsa/sieparser/MissingFieldException.java b/src/main/java/alipsa/sieparser/MissingFieldException.java
index 235b126..ec20c0b 100644
--- a/src/main/java/alipsa/sieparser/MissingFieldException.java
+++ b/src/main/java/alipsa/sieparser/MissingFieldException.java
@@ -38,4 +38,14 @@ public class MissingFieldException extends SieException {
     public MissingFieldException(String s) {
         super(s);
     }
+
+    /**
+     * Creates a new MissingFieldException with the given message and cause.
+     *
+     * @param s the detail message describing which field is missing
+     * @param cause the underlying cause
+     */
+    public MissingFieldException(String s, Throwable cause) {
+        super(s, cause);
+    }
 }
diff --git a/src/main/java/alipsa/sieparser/SieCRC32.java b/src/main/java/alipsa/sieparser/SieCRC32.java
index 225924c..502266a 100644
--- a/src/main/java/alipsa/sieparser/SieCRC32.java
+++ b/src/main/java/alipsa/sieparser/SieCRC32.java
@@ -25,9 +25,6 @@ of this software and associated documentation files (the "Software"), to deal
 
 package alipsa.sieparser;
 
-import java.util.ArrayList;
-import java.util.List;
-
 /**
  * Implementation of the CRC32 checksum algorithm as specified in the SIE file format (#KSUMMA).
  * Used to verify the integrity of SIE file data.
@@ -79,13 +76,11 @@ public void start() {
      * @param item the data item to include in the checksum
      */
     public void addData(SieDataItem item) {
-        List<Byte> buffer = new ArrayList<>();
-        buffer.addAll(Encoding.getBytes(item.getItemType()));
+        crcAccumulate(Encoding.getBytes(item.getItemType()));
         for (String d : item.getData()) {
             String foo = d.replace("{", "").replace("}", "");
-            buffer.addAll(Encoding.getBytes(foo));
+            crcAccumulate(Encoding.getBytes(foo));
         }
-        cRC_accumulate(buffer);
     }
 
     /**
@@ -96,12 +91,12 @@ public long checksum() {
         return (~crc);
     }
 
-    private void cRC_accumulate(List<Byte> buffer) {
+    private void crcAccumulate(byte[] buffer) {
         long temp1;
         long temp2;
-        for (Byte p : buffer) {
+        for (byte p : buffer) {
             temp1 = (crc >> 8) & 0x00FFFFFF;
-            temp2 = CRCTable[((int) crc ^ p.byteValue()) & 0xff];
+            temp2 = CRCTable[((int) crc ^ p) & 0xff];
             crc = temp1 ^ temp2;
         }
     }
diff --git a/src/main/java/alipsa/sieparser/SieDataItem.java b/src/main/java/alipsa/sieparser/SieDataItem.java
index 82aa090..49f83e9 100644
--- a/src/main/java/alipsa/sieparser/SieDataItem.java
+++ b/src/main/java/alipsa/sieparser/SieDataItem.java
@@ -265,13 +265,18 @@ public LocalDate getDate(int field) {
         if (foo.isEmpty()) return null;
 
         if (foo.length() != 8) {
-            getDocumentReader().callbacks.callbackException(new SieDateException(foo + " is not a valid date"));
+            getDocumentReader().getCallbacks().callbackException(new SieDateException(foo + " is not a valid date"));
+            return null;
+        }
+        try {
+            int y = Integer.parseInt(foo.substring(0, 4));
+            int m = Integer.parseInt(foo.substring(4, 6));
+            int d = Integer.parseInt(foo.substring(6, 8));
+            return LocalDate.of(y, m, d);
+        } catch (NumberFormatException | java.time.DateTimeException e) {
+            getDocumentReader().getCallbacks().callbackException(new SieDateException(foo + " is not a valid date"));
             return null;
         }
-        int y = Integer.parseInt(foo.substring(0, 4));
-        int m = Integer.parseInt(foo.substring(4, 6));
-        int d = Integer.parseInt(foo.substring(6, 8));
-        return LocalDate.of(y, m, d);
     }
 
     /**
@@ -292,7 +297,7 @@ public List<SieObject> getObjects() {
             }
         }
         if (data == null) {
-            getDocumentReader().callbacks.callbackException(new SieMissingObjectException(getRawData()));
+            getDocumentReader().getCallbacks().callbackException(new SieMissingObjectException(getRawData()));
             return null;
         }
 
diff --git a/src/main/java/alipsa/sieparser/SieDateException.java b/src/main/java/alipsa/sieparser/SieDateException.java
index 3b6ecb3..0926b0e 100644
--- a/src/main/java/alipsa/sieparser/SieDateException.java
+++ b/src/main/java/alipsa/sieparser/SieDateException.java
@@ -40,4 +40,13 @@ public SieDateException(String description) {
         super(description);
     }
 
+    /**
+     * Creates a new SieDateException with the given description and cause.
+     *
+     * @param description a message describing the invalid date
+     * @param cause the underlying cause
+     */
+    public SieDateException(String description, Throwable cause) {
+        super(description, cause);
+    }
 }
diff --git a/src/main/java/alipsa/sieparser/SieDocument.java b/src/main/java/alipsa/sieparser/SieDocument.java
index d7c29b9..1d973c0 100644
--- a/src/main/java/alipsa/sieparser/SieDocument.java
+++ b/src/main/java/alipsa/sieparser/SieDocument.java
@@ -471,13 +471,11 @@ public void setUB(List<SiePeriodValue> value) {
     }
 
     /**
-     * Returns the currency code (#VALUTA), or an empty string if not set.
-     * @return the currency code
+     * Returns the currency code (#VALUTA), or {@code null} if not set.
+     * Per the SIE specification, if this post is absent the reader should assume SEK.
+     * @return the currency code, or {@code null} if not set
      */
     public String getVALUTA() {
-        if (valuta == null) {
-            return "";
-        }
         return valuta;
     }
 
diff --git a/src/main/java/alipsa/sieparser/SieDocumentComparer.java b/src/main/java/alipsa/sieparser/SieDocumentComparer.java
index a411513..6f63b5d 100644
--- a/src/main/java/alipsa/sieparser/SieDocumentComparer.java
+++ b/src/main/java/alipsa/sieparser/SieDocumentComparer.java
@@ -120,7 +120,7 @@ private void compareNonListItems() {
         if (docA.getTAXAR() != docB.getTAXAR())
             errors.add("TAXAR differs First, Second: '" + docA.getTAXAR() + "' , '" + docB.getTAXAR() + "'");
 
-        if (!docA.getVALUTA().equals(docB.getVALUTA()))
+        if (!StringUtil.equals(docA.getVALUTA(), docB.getVALUTA()))
             errors.add("VALUTA differs First, Second: '" + docA.getVALUTA() + "' , '" + docB.getVALUTA() + "'");
     }
 
diff --git a/src/main/java/alipsa/sieparser/SieDocumentReader.java b/src/main/java/alipsa/sieparser/SieDocumentReader.java
index 01ab924..36617f1 100644
--- a/src/main/java/alipsa/sieparser/SieDocumentReader.java
+++ b/src/main/java/alipsa/sieparser/SieDocumentReader.java
@@ -31,7 +31,9 @@ of this software and associated documentation files (the "Software"), to deal
 import java.time.LocalDate;
 import java.util.ArrayList;
 import java.util.EnumSet;
+import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.function.Consumer;
 
 /**
@@ -41,33 +43,151 @@ of this software and associated documentation files (the "Software"), to deal
  */
 public class SieDocumentReader {
 
-    /** Callbacks invoked during document reading for streaming processing. */
-    public SieCallbacks callbacks = new SieCallbacks();
-    /** When {@code true}, #BTRANS rows are ignored during parsing. */
-    public boolean ignoreBTRANS = false;
-    /** When {@code true}, a missing #OMFATTN is not treated as a validation error. */
-    public boolean ignoreMissingOMFATTNING = false;
-    /** When {@code true}, #RTRANS rows are ignored during parsing. */
-    public boolean ignoreRTRANS = false;
-    /** When {@code true}, vouchers whose rows do not sum to zero are accepted. */
-    public boolean allowUnbalancedVoucher = false;
-    /** When {@code true}, the #KSUMMA checksum is not verified. */
-    public boolean ignoreKSUMMA = false;
-    /** When {@code true}, #UNDERDIM definitions are allowed. */
-    public boolean allowUnderDimensions = false;
-    /** When {@code true}, references to undefined dimensions are accepted. */
-    public boolean ignoreMissingDIM = false;
+    private SieCallbacks callbacks = new SieCallbacks();
+    private boolean ignoreBTRANS = false;
+    private boolean ignoreMissingOMFATTNING = false;
+    private boolean ignoreRTRANS = false;
+    private boolean allowUnbalancedVoucher = false;
+    private boolean ignoreKSUMMA = false;
+    private boolean allowUnderDimensions = false;
+    private boolean ignoreMissingDIM = false;
     private EnumSet<SieType> acceptSIETypes = null;
     private SieDocument sieDocument;
     private List<Exception> validationExceptions;
-    /** When {@code true}, period values are only streamed via callbacks and not stored in the document. */
-    public boolean streamValues = false;
-    /** The CRC32 calculator used for checksum verification. */
-    public SieCRC32 CRC = new SieCRC32();
-    /** When {@code true}, parsing errors are thrown as exceptions instead of being silently collected. */
-    public boolean throwErrors = true;
+    private boolean streamValues = false;
+    private SieCRC32 CRC = new SieCRC32();
+    private boolean throwErrors = true;
     private String fileName;
     private int parsingLineNumber = 0;
+    private SieVoucher curVoucher;
+    private boolean abortParsing;
+    private final Map<String, Consumer<SieDataItem>> handlers = new LinkedHashMap<>();
+
+    /**
+     * Returns the callbacks invoked during document reading.
+     * @return the callbacks
+     */
+    public SieCallbacks getCallbacks() { return callbacks; }
+
+    /**
+     * Sets the callbacks invoked during document reading.
+     * @param callbacks the callbacks to use
+     */
+    public void setCallbacks(SieCallbacks callbacks) { this.callbacks = callbacks; }
+
+    /**
+     * Returns whether #BTRANS rows are ignored during parsing.
+     * @return true if #BTRANS rows are ignored
+     */
+    public boolean isIgnoreBTRANS() { return ignoreBTRANS; }
+
+    /**
+     * Sets whether #BTRANS rows are ignored during parsing.
+     * @param ignoreBTRANS true to ignore #BTRANS rows
+     */
+    public void setIgnoreBTRANS(boolean ignoreBTRANS) { this.ignoreBTRANS = ignoreBTRANS; }
+
+    /**
+     * Returns whether a missing #OMFATTN is accepted.
+     * @return true if a missing #OMFATTN is accepted
+     */
+    public boolean isIgnoreMissingOMFATTNING() { return ignoreMissingOMFATTNING; }
+
+    /**
+     * Sets whether a missing #OMFATTN is accepted.
+     * @param ignoreMissingOMFATTNING true to accept a missing #OMFATTN
+     */
+    public void setIgnoreMissingOMFATTNING(boolean ignoreMissingOMFATTNING) { this.ignoreMissingOMFATTNING = ignoreMissingOMFATTNING; }
+
+    /**
+     * Returns whether #RTRANS rows are ignored during parsing.
+     * @return true if #RTRANS rows are ignored
+     */
+    public boolean isIgnoreRTRANS() { return ignoreRTRANS; }
+
+    /**
+     * Sets whether #RTRANS rows are ignored during parsing.
+     * @param ignoreRTRANS true to ignore #RTRANS rows
+     */
+    public void setIgnoreRTRANS(boolean ignoreRTRANS) { this.ignoreRTRANS = ignoreRTRANS; }
+
+    /**
+     * Returns whether unbalanced vouchers are accepted.
+     * @return true if unbalanced vouchers are accepted
+     */
+    public boolean isAllowUnbalancedVoucher() { return allowUnbalancedVoucher; }
+
+    /**
+     * Sets whether unbalanced vouchers are accepted.
+     * @param allowUnbalancedVoucher true to accept unbalanced vouchers
+     */
+    public void setAllowUnbalancedVoucher(boolean allowUnbalancedVoucher) { this.allowUnbalancedVoucher = allowUnbalancedVoucher; }
+
+    /**
+     * Returns whether the #KSUMMA checksum is ignored.
+     * @return true if the checksum is ignored
+     */
+    public boolean isIgnoreKSUMMA() { return ignoreKSUMMA; }
+
+    /**
+     * Sets whether the #KSUMMA checksum is ignored.
+     * @param ignoreKSUMMA true to ignore the checksum
+     */
+    public void setIgnoreKSUMMA(boolean ignoreKSUMMA) { this.ignoreKSUMMA = ignoreKSUMMA; }
+
+    /**
+     * Returns whether #UNDERDIM definitions are allowed.
+     * @return true if #UNDERDIM is allowed
+     */
+    public boolean isAllowUnderDimensions() { return allowUnderDimensions; }
+
+    /**
+     * Sets whether #UNDERDIM definitions are allowed.
+     * @param allowUnderDimensions true to allow #UNDERDIM
+     */
+    public void setAllowUnderDimensions(boolean allowUnderDimensions) { this.allowUnderDimensions = allowUnderDimensions; }
+
+    /**
+     * Returns whether references to undefined dimensions are accepted.
+     * @return true if undefined dimension references are accepted
+     */
+    public boolean isIgnoreMissingDIM() { return ignoreMissingDIM; }
+
+    /**
+     * Sets whether references to undefined dimensions are accepted.
+     * @param ignoreMissingDIM true to accept undefined dimension references
+     */
+    public void setIgnoreMissingDIM(boolean ignoreMissingDIM) { this.ignoreMissingDIM = ignoreMissingDIM; }
+
+    /**
+     * Returns whether period values are only streamed via callbacks and not stored in the document.
+     * @return true if values are streamed only
+     */
+    public boolean isStreamValues() { return streamValues; }
+
+    /**
+     * Sets whether period values are only streamed via callbacks and not stored in the document.
+     * @param streamValues true to stream values only
+     */
+    public void setStreamValues(boolean streamValues) { this.streamValues = streamValues; }
+
+    /**
+     * Returns the CRC32 calculator used for checksum verification.
+     * @return the CRC32 calculator
+     */
+    public SieCRC32 getCRC() { return CRC; }
+
+    /**
+     * Returns whether parsing errors are thrown as exceptions instead of being silently collected.
+     * @return true if errors are thrown
+     */
+    public boolean isThrowErrors() { return throwErrors; }
+
+    /**
+     * Sets whether parsing errors are thrown as exceptions instead of being silently collected.
+     * @param throwErrors true to throw errors as exceptions
+     */
+    public void setThrowErrors(boolean throwErrors) { this.throwErrors = throwErrors; }
 
     /**
      * Returns the SIE type version from a file without fully parsing it.
@@ -93,6 +213,7 @@ public static int getSieVersion(String fileName) throws IOException {
     public SieDocumentReader() {
         sieDocument = new SieDocument();
         setValidationExceptions(new ArrayList<>());
+        initHandlers();
     }
 
     /**
@@ -142,6 +263,9 @@ public void setAcceptSIETypes(EnumSet<SieType> acceptSIETypes) {
      */
     public SieDocument readDocument(String fileName) throws IOException {
         this.fileName = fileName;
+        curVoucher = null;
+        abortParsing = false;
+
         if (throwErrors) {
             Consumer<Exception> existing = callbacks.getSieException();
             callbacks.setSieException(ex -> {
@@ -151,7 +275,6 @@ public SieDocument readDocument(String fileName) throws IOException {
             });
         }
 
-        SieVoucher curVoucher = null;
         boolean firstLine = true;
         parsingLineNumber = 0;
 
@@ -171,141 +294,20 @@ public SieDocument readDocument(String fileName) throws IOException {
                 if (!ignoreKSUMMA && CRC.isStarted() && !SIE.KSUMMA.equals(di.getItemType()))
                     CRC.addData(di);
 
-                SiePeriodValue pv;
                 String itemType = di.getItemType();
-                if (SIE.ADRESS.equals(itemType)) {
-                    sieDocument.getFNAMN().setContact(di.getString(0));
-                    sieDocument.getFNAMN().setStreet(di.getString(1));
-                    sieDocument.getFNAMN().setZipCity(di.getString(2));
-                    sieDocument.getFNAMN().setPhone(di.getString(3));
-                } else if (SIE.BKOD.equals(itemType)) {
-                    sieDocument.getFNAMN().setSni(di.getInt(0));
-                } else if (SIE.BTRANS.equals(itemType)) {
-                    if (!ignoreBTRANS) {
-                        if (curVoucher == null) {
-                            callbacks.callbackException(new SieParseException(
-                                "#BTRANS outside #VER block at line " + parsingLineNumber));
-                        } else {
-                            parseTRANS(di, curVoucher);
-                        }
-                    }
-                } else if (SIE.DIM.equals(itemType)) {
-                    parseDimension(di);
-                } else if (SIE.ENHET.equals(itemType)) {
-                    parseENHET(di);
-                } else if (SIE.FLAGGA.equals(itemType)) {
-                    sieDocument.setFLAGGA(di.getInt(0));
-                } else if (SIE.FNAMN.equals(itemType)) {
-                    sieDocument.getFNAMN().setName(di.getString(0));
-                } else if (SIE.FNR.equals(itemType)) {
-                    sieDocument.getFNAMN().setCode(di.getString(0));
-                } else if (SIE.FORMAT.equals(itemType)) {
-                    sieDocument.setFORMAT(di.getString(0));
-                } else if (SIE.FTYP.equals(itemType)) {
-                    sieDocument.getFNAMN().setOrgType(di.getString(0));
-                } else if (SIE.GEN.equals(itemType)) {
-                    sieDocument.setGEN_DATE(di.getDate(0));
-                    sieDocument.setGEN_NAMN(di.getString(1));
-                } else if (SIE.IB.equals(itemType)) {
-                    parseIB(di);
-                } else if (SIE.KONTO.equals(itemType)) {
-                    parseKONTO(di);
-                } else if (SIE.KSUMMA.equals(itemType)) {
-                    if (!ignoreKSUMMA) {
-                        if (CRC.isStarted()) {
-                            parseKSUMMA(di);
-                        } else {
-                            CRC.start();
-                        }
-                    }
-                } else if (SIE.KTYP.equals(itemType)) {
-                    parseKTYP(di);
-                } else if (SIE.KPTYP.equals(itemType)) {
-                    sieDocument.setKPTYP(di.getString(0));
-                } else if (SIE.OBJEKT.equals(itemType)) {
-                    parseOBJEKT(di);
-                } else if (SIE.OIB.equals(itemType)) {
-                    pv = parseOIB_OUB(di);
-                    callbacks.callbackOIB(pv);
-                    if (!streamValues) sieDocument.getOIB().add(pv);
-                } else if (SIE.OUB.equals(itemType)) {
-                    pv = parseOIB_OUB(di);
-                    callbacks.callbackOUB(pv);
-                    if (!streamValues) sieDocument.getOUB().add(pv);
-                } else if (SIE.ORGNR.equals(itemType)) {
-                    sieDocument.getFNAMN().setOrgIdentifier(di.getString(0));
-                } else if (SIE.OMFATTN.equals(itemType)) {
-                    sieDocument.setOMFATTN(di.getDate(0));
-                } else if (SIE.PBUDGET.equals(itemType)) {
-                    pv = parsePBUDGET_PSALDO(di);
-                    if (pv != null) {
-                        callbacks.callbackPBUDGET(pv);
-                        if (!streamValues) sieDocument.getPBUDGET().add(pv);
-                    }
-                } else if (SIE.PROGRAM.equals(itemType)) {
-                    sieDocument.setPROGRAM(di.getData());
-                } else if (SIE.PROSA.equals(itemType)) {
-                    sieDocument.setPROSA(di.getString(0));
-                } else if (SIE.PSALDO.equals(itemType)) {
-                    pv = parsePBUDGET_PSALDO(di);
-                    if (pv != null) {
-                        callbacks.callbackPSALDO(pv);
-                        if (!streamValues) sieDocument.getPSALDO().add(pv);
-                    }
-                } else if (SIE.RAR.equals(itemType)) {
-                    parseRAR(di);
-                } else if (SIE.RTRANS.equals(itemType)) {
-                    if (!ignoreRTRANS) {
-                        if (curVoucher == null) {
-                            callbacks.callbackException(new SieParseException(
-                                "#RTRANS outside #VER block at line " + parsingLineNumber));
-                        } else {
-                            parseTRANS(di, curVoucher);
-                        }
-                    }
-                } else if (SIE.SIETYP.equals(itemType)) {
-                    sieDocument.setSIETYP(di.getInt(0));
-                    if (acceptSIETypes != null) {
-                        try {
-                            SieType parsed = SieType.fromValue(di.getInt(0));
-                            if (!acceptSIETypes.contains(parsed)) {
-                                callbacks.callbackException(new SieInvalidFeatureException(
-                                    "SIE type " + di.getInt(0) + " is not accepted"));
-                                return null;
-                            }
-                        } catch (IllegalArgumentException e) {
-                            callbacks.callbackException(new SieInvalidFeatureException(
-                                "Unknown SIE type: " + di.getInt(0)));
-                        }
-                    }
-                } else if (SIE.SRU.equals(itemType)) {
-                    parseSRU(di);
-                } else if (SIE.TAXAR.equals(itemType)) {
-                    sieDocument.setTAXAR(di.getInt(0));
-                } else if (SIE.UB.equals(itemType)) {
-                    parseUB(di);
-                } else if (SIE.TRANS.equals(itemType)) {
-                    if (curVoucher == null) {
-                        callbacks.callbackException(new SieParseException(
-                            "#TRANS outside #VER block at line " + parsingLineNumber));
-                    } else {
-                        parseTRANS(di, curVoucher);
-                    }
-                } else if (SIE.RES.equals(itemType)) {
-                    parseRES(di);
-                } else if (SIE.UNDERDIM.equals(itemType)) {
-                    parseUnderDimension(di);
-                } else if (SIE.VALUTA.equals(itemType)) {
-                    sieDocument.setVALUTA(di.getString(0));
-                } else if (SIE.VER.equals(itemType)) {
-                    curVoucher = parseVER(di);
-                } else if ("".equals(itemType)) {
-                } else if ("{".equals(itemType)) {
+                if ("".equals(itemType) || "{".equals(itemType)) {
+                    // blank lines and opening braces are ignored
                 } else if ("}".equals(itemType)) {
                     if (curVoucher != null) closeVoucher(curVoucher);
                     curVoucher = null;
                 } else {
-                    callbacks.callbackException(new UnsupportedOperationException(di.getItemType()));
+                    Consumer<SieDataItem> handler = handlers.get(itemType);
+                    if (handler != null) {
+                        handler.accept(di);
+                        if (abortParsing) return null;
+                    } else {
+                        callbacks.callbackException(new UnsupportedOperationException(di.getItemType()));
+                    }
                 }
             }
         }
@@ -319,6 +321,143 @@ public SieDocument readDocument(String fileName) throws IOException {
         return sieDocument;
     }
 
+    private void initHandlers() {
+        handlers.put(SIE.ADRESS, this::handleADRESS);
+        handlers.put(SIE.BKOD, di -> sieDocument.getFNAMN().setSni(di.getInt(0)));
+        handlers.put(SIE.BTRANS, this::handleBTRANS);
+        handlers.put(SIE.DIM, this::parseDimension);
+        handlers.put(SIE.ENHET, this::parseENHET);
+        handlers.put(SIE.FLAGGA, di -> sieDocument.setFLAGGA(di.getInt(0)));
+        handlers.put(SIE.FNAMN, di -> sieDocument.getFNAMN().setName(di.getString(0)));
+        handlers.put(SIE.FNR, di -> sieDocument.getFNAMN().setCode(di.getString(0)));
+        handlers.put(SIE.FORMAT, di -> sieDocument.setFORMAT(di.getString(0)));
+        handlers.put(SIE.FTYP, di -> sieDocument.getFNAMN().setOrgType(di.getString(0)));
+        handlers.put(SIE.GEN, this::handleGEN);
+        handlers.put(SIE.IB, this::parseIB);
+        handlers.put(SIE.KONTO, this::parseKONTO);
+        handlers.put(SIE.KSUMMA, this::handleKSUMMA);
+        handlers.put(SIE.KTYP, this::parseKTYP);
+        handlers.put(SIE.KPTYP, di -> sieDocument.setKPTYP(di.getString(0)));
+        handlers.put(SIE.OBJEKT, this::parseOBJEKT);
+        handlers.put(SIE.OIB, this::handleOIB);
+        handlers.put(SIE.OUB, this::handleOUB);
+        handlers.put(SIE.ORGNR, di -> sieDocument.getFNAMN().setOrgIdentifier(di.getString(0)));
+        handlers.put(SIE.OMFATTN, di -> sieDocument.setOMFATTN(di.getDate(0)));
+        handlers.put(SIE.PBUDGET, this::handlePBUDGET);
+        handlers.put(SIE.PROGRAM, di -> sieDocument.setPROGRAM(di.getData()));
+        handlers.put(SIE.PROSA, di -> sieDocument.setPROSA(di.getString(0)));
+        handlers.put(SIE.PSALDO, this::handlePSALDO);
+        handlers.put(SIE.RAR, this::parseRAR);
+        handlers.put(SIE.RTRANS, this::handleRTRANS);
+        handlers.put(SIE.SIETYP, this::handleSIETYP);
+        handlers.put(SIE.SRU, this::parseSRU);
+        handlers.put(SIE.TAXAR, di -> sieDocument.setTAXAR(di.getInt(0)));
+        handlers.put(SIE.UB, this::parseUB);
+        handlers.put(SIE.TRANS, this::handleTRANS);
+        handlers.put(SIE.RES, this::parseRES);
+        handlers.put(SIE.UNDERDIM, this::parseUnderDimension);
+        handlers.put(SIE.VALUTA, di -> sieDocument.setVALUTA(di.getString(0)));
+        handlers.put(SIE.VER, di -> curVoucher = parseVER(di));
+    }
+
+    private void handleADRESS(SieDataItem di) {
+        sieDocument.getFNAMN().setContact(di.getString(0));
+        sieDocument.getFNAMN().setStreet(di.getString(1));
+        sieDocument.getFNAMN().setZipCity(di.getString(2));
+        sieDocument.getFNAMN().setPhone(di.getString(3));
+    }
+
+    private void handleGEN(SieDataItem di) {
+        sieDocument.setGEN_DATE(di.getDate(0));
+        sieDocument.setGEN_NAMN(di.getString(1));
+    }
+
+    private void handleBTRANS(SieDataItem di) {
+        if (!ignoreBTRANS) {
+            if (curVoucher == null) {
+                callbacks.callbackException(new SieParseException(
+                    "#BTRANS outside #VER block at line " + parsingLineNumber));
+            } else {
+                parseTRANS(di, curVoucher);
+            }
+        }
+    }
+
+    private void handleRTRANS(SieDataItem di) {
+        if (!ignoreRTRANS) {
+            if (curVoucher == null) {
+                callbacks.callbackException(new SieParseException(
+                    "#RTRANS outside #VER block at line " + parsingLineNumber));
+            } else {
+                parseTRANS(di, curVoucher);
+            }
+        }
+    }
+
+    private void handleTRANS(SieDataItem di) {
+        if (curVoucher == null) {
+            callbacks.callbackException(new SieParseException(
+                "#TRANS outside #VER block at line " + parsingLineNumber));
+        } else {
+            parseTRANS(di, curVoucher);
+        }
+    }
+
+    private void handleKSUMMA(SieDataItem di) {
+        if (!ignoreKSUMMA) {
+            if (CRC.isStarted()) {
+                parseKSUMMA(di);
+            } else {
+                CRC.start();
+            }
+        }
+    }
+
+    private void handleSIETYP(SieDataItem di) {
+        sieDocument.setSIETYP(di.getInt(0));
+        if (acceptSIETypes != null) {
+            try {
+                SieType parsed = SieType.fromValue(di.getInt(0));
+                if (!acceptSIETypes.contains(parsed)) {
+                    callbacks.callbackException(new SieInvalidFeatureException(
+                        "SIE type " + di.getInt(0) + " is not accepted"));
+                    abortParsing = true;
+                }
+            } catch (IllegalArgumentException e) {
+                callbacks.callbackException(new SieInvalidFeatureException(
+                    "Unknown SIE type: " + di.getInt(0)));
+            }
+        }
+    }
+
+    private void handleOIB(SieDataItem di) {
+        SiePeriodValue pv = parseOIB_OUB(di);
+        callbacks.callbackOIB(pv);
+        if (!streamValues) sieDocument.getOIB().add(pv);
+    }
+
+    private void handleOUB(SieDataItem di) {
+        SiePeriodValue pv = parseOIB_OUB(di);
+        callbacks.callbackOUB(pv);
+        if (!streamValues) sieDocument.getOUB().add(pv);
+    }
+
+    private void handlePBUDGET(SieDataItem di) {
+        SiePeriodValue pv = parsePBUDGET_PSALDO(di);
+        if (pv != null) {
+            callbacks.callbackPBUDGET(pv);
+            if (!streamValues) sieDocument.getPBUDGET().add(pv);
+        }
+    }
+
+    private void handlePSALDO(SieDataItem di) {
+        SiePeriodValue pv = parsePBUDGET_PSALDO(di);
+        if (pv != null) {
+            callbacks.callbackPSALDO(pv);
+            if (!streamValues) sieDocument.getPSALDO().add(pv);
+        }
+    }
+
     private void parseRAR(SieDataItem di) {
         SieBookingYear rar = new SieBookingYear();
         rar.setId(di.getInt(0));
@@ -602,7 +741,7 @@ private void closeVoucher(SieVoucher v) {
                 check = check.add(r.getAmount());
             }
             if (check.compareTo(BigDecimal.ZERO) != 0)
-                callbacks.callbackException(new SieVoucherMissmatchException(
+                callbacks.callbackException(new SieVoucherMismatchException(
                     v.getSeries() + "." + v.getNumber() + " Sum is not zero."));
         }
 
diff --git a/src/main/java/alipsa/sieparser/SieDocumentWriter.java b/src/main/java/alipsa/sieparser/SieDocumentWriter.java
index 8693ae5..e39da94 100644
--- a/src/main/java/alipsa/sieparser/SieDocumentWriter.java
+++ b/src/main/java/alipsa/sieparser/SieDocumentWriter.java
@@ -68,9 +68,6 @@ public SieDocumentWriter(SieDocument sie, WriteOptions options) {
      * @throws IOException if an I/O error occurs
      */
     public void write(String fileName) throws IOException {
-        File file = new File(fileName);
-        if (file.exists()) file.delete();
-
         try (BufferedWriter bw = IoUtil.getWriter(fileName)) {
             writer = bw;
             writeContent();
@@ -329,12 +326,17 @@ private void writeKPTYP() throws IOException {
     }
 
     private void writeADRESS() throws IOException {
-        if (!(sieDoc.getFNAMN().getContact() == null && sieDoc.getFNAMN().getStreet() == null && sieDoc.getFNAMN().getZipCity() == null && sieDoc.getFNAMN().getPhone() == null)) {
-            writeLine(SIE.ADRESS + " \"" + sieDoc.getFNAMN().getContact() + "\" \"" + sieDoc.getFNAMN().getStreet() +
-                    "\" \"" + sieDoc.getFNAMN().getZipCity() + "\" \"" + sieDoc.getFNAMN().getPhone() + "\"");
+        SieCompany fnamn = sieDoc.getFNAMN();
+        if (!(fnamn.getContact() == null && fnamn.getStreet() == null && fnamn.getZipCity() == null && fnamn.getPhone() == null)) {
+            writeLine(SIE.ADRESS + " \"" + nullToEmpty(fnamn.getContact()) + "\" \"" + nullToEmpty(fnamn.getStreet()) +
+                    "\" \"" + nullToEmpty(fnamn.getZipCity()) + "\" \"" + nullToEmpty(fnamn.getPhone()) + "\"");
         }
     }
 
+    private static String nullToEmpty(String s) {
+        return s == null ? "" : s;
+    }
+
     private String getFNAMN() {
         return SIE.FNAMN + " \"" + sieDoc.getFNAMN().getName() + "\"";
     }
diff --git a/src/main/java/alipsa/sieparser/SieInvalidChecksumException.java b/src/main/java/alipsa/sieparser/SieInvalidChecksumException.java
index 419e98e..59ab719 100644
--- a/src/main/java/alipsa/sieparser/SieInvalidChecksumException.java
+++ b/src/main/java/alipsa/sieparser/SieInvalidChecksumException.java
@@ -39,4 +39,13 @@ public SieInvalidChecksumException(String description) {
         super(description);
     }
 
+    /**
+     * Creates a new SieInvalidChecksumException with the given description and cause.
+     *
+     * @param description a message describing the checksum mismatch
+     * @param cause the underlying cause
+     */
+    public SieInvalidChecksumException(String description, Throwable cause) {
+        super(description, cause);
+    }
 }
diff --git a/src/main/java/alipsa/sieparser/SieInvalidFeatureException.java b/src/main/java/alipsa/sieparser/SieInvalidFeatureException.java
index c744f98..0010e5a 100644
--- a/src/main/java/alipsa/sieparser/SieInvalidFeatureException.java
+++ b/src/main/java/alipsa/sieparser/SieInvalidFeatureException.java
@@ -40,4 +40,13 @@ public SieInvalidFeatureException(String description) {
         super(description);
     }
 
+    /**
+     * Creates a new SieInvalidFeatureException with the given description and cause.
+     *
+     * @param description a message describing the invalid feature usage
+     * @param cause the underlying cause
+     */
+    public SieInvalidFeatureException(String description, Throwable cause) {
+        super(description, cause);
+    }
 }
diff --git a/src/main/java/alipsa/sieparser/SieInvalidFileException.java b/src/main/java/alipsa/sieparser/SieInvalidFileException.java
index 1af5766..8f07d4b 100644
--- a/src/main/java/alipsa/sieparser/SieInvalidFileException.java
+++ b/src/main/java/alipsa/sieparser/SieInvalidFileException.java
@@ -40,4 +40,13 @@ public SieInvalidFileException(String description) {
         super(description);
     }
 
+    /**
+     * Creates a new SieInvalidFileException with the given description and cause.
+     *
+     * @param description a message identifying the invalid file
+     * @param cause the underlying cause
+     */
+    public SieInvalidFileException(String description, Throwable cause) {
+        super(description, cause);
+    }
 }
diff --git a/src/main/java/alipsa/sieparser/SieMissingMandatoryDateException.java b/src/main/java/alipsa/sieparser/SieMissingMandatoryDateException.java
index 23537f1..48d6a2b 100644
--- a/src/main/java/alipsa/sieparser/SieMissingMandatoryDateException.java
+++ b/src/main/java/alipsa/sieparser/SieMissingMandatoryDateException.java
@@ -39,4 +39,13 @@ public SieMissingMandatoryDateException(String description) {
         super(description);
     }
 
+    /**
+     * Creates a new SieMissingMandatoryDateException with the given description and cause.
+     *
+     * @param description a message describing which date is missing
+     * @param cause the underlying cause
+     */
+    public SieMissingMandatoryDateException(String description, Throwable cause) {
+        super(description, cause);
+    }
 }
diff --git a/src/main/java/alipsa/sieparser/SieMissingObjectException.java b/src/main/java/alipsa/sieparser/SieMissingObjectException.java
index 9e77172..23e7c30 100644
--- a/src/main/java/alipsa/sieparser/SieMissingObjectException.java
+++ b/src/main/java/alipsa/sieparser/SieMissingObjectException.java
@@ -39,4 +39,13 @@ public SieMissingObjectException(String description) {
         super(description);
     }
 
+    /**
+     * Creates a new SieMissingObjectException with the given description and cause.
+     *
+     * @param description a message describing the missing object
+     * @param cause the underlying cause
+     */
+    public SieMissingObjectException(String description, Throwable cause) {
+        super(description, cause);
+    }
 }
diff --git a/src/main/java/alipsa/sieparser/SiePeriodValue.java b/src/main/java/alipsa/sieparser/SiePeriodValue.java
index 80d105b..6f45ad5 100644
--- a/src/main/java/alipsa/sieparser/SiePeriodValue.java
+++ b/src/main/java/alipsa/sieparser/SiePeriodValue.java
@@ -170,17 +170,4 @@ public String getToken() {
     public void setToken(String token) {
         this.token = token;
     }
-
-    /*
-    public SieVoucherRow toVoucherRow() throws Exception {
-        SieVoucherRow vr = new SieVoucherRow();
-        return vr;
-    }
-
-    public SieVoucherRow toInvertedVoucherRow() throws Exception {
-        SieVoucherRow vr = toVoucherRow();
-        vr.setAmount(vr.getAmount() * -1);
-        return vr;
-    }
-    */
 }
diff --git a/src/main/java/alipsa/sieparser/SieVoucherMissmatchException.java b/src/main/java/alipsa/sieparser/SieVoucherMismatchException.java
similarity index 71%
rename from src/main/java/alipsa/sieparser/SieVoucherMissmatchException.java
rename to src/main/java/alipsa/sieparser/SieVoucherMismatchException.java
index a15bb46..454c068 100644
--- a/src/main/java/alipsa/sieparser/SieVoucherMissmatchException.java
+++ b/src/main/java/alipsa/sieparser/SieVoucherMismatchException.java
@@ -29,14 +29,23 @@ of this software and associated documentation files (the "Software"), to deal
 /**
  * Thrown when the transaction rows of a voucher do not sum to zero.
  */
-public class SieVoucherMissmatchException extends SieException {
+public class SieVoucherMismatchException extends SieException {
     /**
-     * Creates a new SieVoucherMissmatchException with the given description.
+     * Creates a new SieVoucherMismatchException with the given description.
      *
      * @param description a message identifying the mismatched voucher
      */
-    public SieVoucherMissmatchException(String description) {
+    public SieVoucherMismatchException(String description) {
         super(description);
     }
 
+    /**
+     * Creates a new SieVoucherMismatchException with the given description and cause.
+     *
+     * @param description a message identifying the mismatched voucher
+     * @param cause the underlying cause
+     */
+    public SieVoucherMismatchException(String description, Throwable cause) {
+        super(description, cause);
+    }
 }
diff --git a/src/main/java/alipsa/sieparser/sie5/Sie5DocumentReader.java b/src/main/java/alipsa/sieparser/sie5/Sie5DocumentReader.java
index 05d484a..31c5d87 100644
--- a/src/main/java/alipsa/sieparser/sie5/Sie5DocumentReader.java
+++ b/src/main/java/alipsa/sieparser/sie5/Sie5DocumentReader.java
@@ -1,5 +1,6 @@
 package alipsa.sieparser.sie5;
 
+import alipsa.sieparser.SieException;
 import jakarta.xml.bind.JAXBContext;
 import jakarta.xml.bind.JAXBException;
 import jakarta.xml.bind.Unmarshaller;
@@ -40,11 +41,15 @@ public Sie5DocumentReader() {}
      *
      * @param fileName the path to the SIE 5 XML file
      * @return the parsed {@link Sie5Document}
-     * @throws JAXBException if the XML cannot be parsed or does not conform to the expected structure
+     * @throws SieException if the XML cannot be parsed or does not conform to the expected structure
      */
-    public Sie5Document readDocument(String fileName) throws JAXBException {
-        Unmarshaller unmarshaller = CONTEXT.createUnmarshaller();
-        return (Sie5Document) unmarshaller.unmarshal(new File(fileName));
+    public Sie5Document readDocument(String fileName) {
+        try {
+            Unmarshaller unmarshaller = CONTEXT.createUnmarshaller();
+            return (Sie5Document) unmarshaller.unmarshal(new File(fileName));
+        } catch (JAXBException e) {
+            throw new SieException("Failed to read SIE 5 document: " + fileName, e);
+        }
     }
 
     /**
@@ -52,11 +57,15 @@ public Sie5Document readDocument(String fileName) throws JAXBException {
      *
      * @param stream the input stream containing SIE 5 XML data
      * @return the parsed {@link Sie5Document}
-     * @throws JAXBException if the XML cannot be parsed or does not conform to the expected structure
+     * @throws SieException if the XML cannot be parsed or does not conform to the expected structure
      */
-    public Sie5Document readDocument(InputStream stream) throws JAXBException {
-        Unmarshaller unmarshaller = CONTEXT.createUnmarshaller();
-        return (Sie5Document) unmarshaller.unmarshal(stream);
+    public Sie5Document readDocument(InputStream stream) {
+        try {
+            Unmarshaller unmarshaller = CONTEXT.createUnmarshaller();
+            return (Sie5Document) unmarshaller.unmarshal(stream);
+        } catch (JAXBException e) {
+            throw new SieException("Failed to read SIE 5 document from stream", e);
+        }
     }
 
     /**
@@ -64,11 +73,15 @@ public Sie5Document readDocument(InputStream stream) throws JAXBException {
      *
      * @param fileName the path to the SIE 5 entry XML file
      * @return the parsed {@link Sie5Entry}
-     * @throws JAXBException if the XML cannot be parsed or does not conform to the expected structure
+     * @throws SieException if the XML cannot be parsed or does not conform to the expected structure
      */
-    public Sie5Entry readEntry(String fileName) throws JAXBException {
-        Unmarshaller unmarshaller = CONTEXT.createUnmarshaller();
-        return (Sie5Entry) unmarshaller.unmarshal(new File(fileName));
+    public Sie5Entry readEntry(String fileName) {
+        try {
+            Unmarshaller unmarshaller = CONTEXT.createUnmarshaller();
+            return (Sie5Entry) unmarshaller.unmarshal(new File(fileName));
+        } catch (JAXBException e) {
+            throw new SieException("Failed to read SIE 5 entry: " + fileName, e);
+        }
     }
 
     /**
@@ -79,10 +92,14 @@ public Sie5Entry readEntry(String fileName) throws JAXBException {
      *
      * @param stream the input stream containing SIE 5 entry XML data
      * @return the parsed {@link Sie5Entry}
-     * @throws JAXBException if the XML cannot be parsed or does not conform to the expected structure
+     * @throws SieException if the XML cannot be parsed or does not conform to the expected structure
      */
-    public Sie5Entry readEntry(InputStream stream) throws JAXBException {
-        Unmarshaller unmarshaller = CONTEXT.createUnmarshaller();
-        return unmarshaller.unmarshal(new StreamSource(stream), Sie5Entry.class).getValue();
+    public Sie5Entry readEntry(InputStream stream) {
+        try {
+            Unmarshaller unmarshaller = CONTEXT.createUnmarshaller();
+            return unmarshaller.unmarshal(new StreamSource(stream), Sie5Entry.class).getValue();
+        } catch (JAXBException e) {
+            throw new SieException("Failed to read SIE 5 entry from stream", e);
+        }
     }
 }
diff --git a/src/main/java/alipsa/sieparser/sie5/Sie5DocumentWriter.java b/src/main/java/alipsa/sieparser/sie5/Sie5DocumentWriter.java
index d68fb43..95f3879 100644
--- a/src/main/java/alipsa/sieparser/sie5/Sie5DocumentWriter.java
+++ b/src/main/java/alipsa/sieparser/sie5/Sie5DocumentWriter.java
@@ -1,5 +1,6 @@
 package alipsa.sieparser.sie5;
 
+import alipsa.sieparser.SieException;
 import jakarta.xml.bind.JAXBContext;
 import jakarta.xml.bind.JAXBException;
 import jakarta.xml.bind.Marshaller;
@@ -38,11 +39,15 @@ public Sie5DocumentWriter() {}
      *
      * @param doc      the document to write
      * @param fileName the path of the output file
-     * @throws JAXBException if the document cannot be marshalled
+     * @throws SieException if the document cannot be marshalled
      */
-    public void write(Sie5Document doc, String fileName) throws JAXBException {
-        Marshaller marshaller = createMarshaller();
-        marshaller.marshal(doc, new File(fileName));
+    public void write(Sie5Document doc, String fileName) {
+        try {
+            Marshaller marshaller = createMarshaller();
+            marshaller.marshal(doc, new File(fileName));
+        } catch (JAXBException e) {
+            throw new SieException("Failed to write SIE 5 document: " + fileName, e);
+        }
     }
 
     /**
@@ -50,11 +55,15 @@ public void write(Sie5Document doc, String fileName) throws JAXBException {
      *
      * @param doc    the document to write
      * @param stream the output stream to write to
-     * @throws JAXBException if the document cannot be marshalled
+     * @throws SieException if the document cannot be marshalled
      */
-    public void write(Sie5Document doc, OutputStream stream) throws JAXBException {
-        Marshaller marshaller = createMarshaller();
-        marshaller.marshal(doc, stream);
+    public void write(Sie5Document doc, OutputStream stream) {
+        try {
+            Marshaller marshaller = createMarshaller();
+            marshaller.marshal(doc, stream);
+        } catch (JAXBException e) {
+            throw new SieException("Failed to write SIE 5 document to stream", e);
+        }
     }
 
     /**
@@ -62,11 +71,15 @@ public void write(Sie5Document doc, OutputStream stream) throws JAXBException {
      *
      * @param entry    the entry document to write
      * @param fileName the path of the output file
-     * @throws JAXBException if the document cannot be marshalled
+     * @throws SieException if the document cannot be marshalled
      */
-    public void writeEntry(Sie5Entry entry, String fileName) throws JAXBException {
-        Marshaller marshaller = createMarshaller();
-        marshaller.marshal(entry, new File(fileName));
+    public void writeEntry(Sie5Entry entry, String fileName) {
+        try {
+            Marshaller marshaller = createMarshaller();
+            marshaller.marshal(entry, new File(fileName));
+        } catch (JAXBException e) {
+            throw new SieException("Failed to write SIE 5 entry: " + fileName, e);
+        }
     }
 
     /**
@@ -74,11 +87,15 @@ public void writeEntry(Sie5Entry entry, String fileName) throws JAXBException {
      *
      * @param entry  the entry document to write
      * @param stream the output stream to write to
-     * @throws JAXBException if the document cannot be marshalled
+     * @throws SieException if the document cannot be marshalled
      */
-    public void writeEntry(Sie5Entry entry, OutputStream stream) throws JAXBException {
-        Marshaller marshaller = createMarshaller();
-        marshaller.marshal(entry, stream);
+    public void writeEntry(Sie5Entry entry, OutputStream stream) {
+        try {
+            Marshaller marshaller = createMarshaller();
+            marshaller.marshal(entry, stream);
+        } catch (JAXBException e) {
+            throw new SieException("Failed to write SIE 5 entry to stream", e);
+        }
     }
 
     private Marshaller createMarshaller() throws JAXBException {
diff --git a/src/test/java/alipsa/sieparser/SieDocumentReaderTest.java b/src/test/java/alipsa/sieparser/SieDocumentReaderTest.java
index 144918b..516e0ca 100644
--- a/src/test/java/alipsa/sieparser/SieDocumentReaderTest.java
+++ b/src/test/java/alipsa/sieparser/SieDocumentReaderTest.java
@@ -1,11 +1,17 @@
 package alipsa.sieparser;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import java.io.File;
 import java.io.IOException;
 import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
 import java.util.EnumSet;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -27,7 +33,7 @@ public void readType2() throws IOException {
         URL url = Thread.currentThread().getContextClassLoader().getResource("samples/1_BL0001_typ2.SE");
         assertNotNull(url);
         SieDocumentReader reader = new SieDocumentReader();
-        reader.ignoreMissingOMFATTNING = true;
+        reader.setIgnoreMissingOMFATTNING(true);
         SieDocument doc = reader.readDocument(new File(url.getFile()).getAbsolutePath());
         assertEquals(2, doc.getSIETYP());
     }
@@ -45,7 +51,7 @@ public void readType4() throws IOException {
     @Test
     public void allowUnbalancedVoucher() throws IOException {
         SieDocumentReader reader = new SieDocumentReader();
-        reader.allowUnbalancedVoucher = true;
+        reader.setAllowUnbalancedVoucher(true);
         assertDoesNotThrow(() -> {
             // Should not throw even if vouchers are unbalanced
             // (the flag prevents the balance check)
@@ -60,7 +66,7 @@ public void acceptSieTypesFilter() throws IOException {
         // Only accept type 2 - should reject type 4 file
         SieDocumentReader reader = new SieDocumentReader();
         reader.setAcceptSIETypes(EnumSet.of(SieType.TYPE_2));
-        reader.throwErrors = true;
+        reader.setThrowErrors(true);
 
         assertThrows(RuntimeException.class, () -> {
             reader.readDocument(new File(url.getFile()).getAbsolutePath());
@@ -85,7 +91,7 @@ public void ignoreKSUMMA() throws IOException {
         assertNotNull(url);
 
         SieDocumentReader reader = new SieDocumentReader();
-        reader.ignoreKSUMMA = true;
+        reader.setIgnoreKSUMMA(true);
         SieDocument doc = reader.readDocument(new File(url.getFile()).getAbsolutePath());
         assertNotNull(doc);
     }
@@ -106,7 +112,7 @@ public void ignoreBTRANS() throws IOException {
         assertNotNull(url);
 
         SieDocumentReader reader = new SieDocumentReader();
-        reader.ignoreBTRANS = true;
+        reader.setIgnoreBTRANS(true);
         SieDocument doc = reader.readDocument(new File(url.getFile()).getAbsolutePath());
         assertNotNull(doc);
 
@@ -148,4 +154,105 @@ public void rarsParsed() throws IOException {
         SieDocument doc = reader.readDocument(new File(url.getFile()).getAbsolutePath());
         assertFalse(doc.getRars().isEmpty(), "Booking years should be parsed");
     }
+
+    @Test
+    public void ignoreRTRANS() throws IOException {
+        URL url = Thread.currentThread().getContextClassLoader().getResource("samples/3_BL0001_typ4.SE");
+        assertNotNull(url);
+
+        SieDocumentReader reader = new SieDocumentReader();
+        reader.setIgnoreRTRANS(true);
+        SieDocument doc = reader.readDocument(new File(url.getFile()).getAbsolutePath());
+        assertNotNull(doc);
+
+        for (SieVoucher v : doc.getVER()) {
+            for (SieVoucherRow r : v.getRows()) {
+                assertNotEquals("#RTRANS", r.getToken());
+            }
+        }
+    }
+
+    @Test
+    public void streamValuesDoesNotStoreInDocument() throws IOException {
+        URL url = Thread.currentThread().getContextClassLoader().getResource("samples/1_BL0001_typ2.SE");
+        assertNotNull(url);
+
+        AtomicInteger ibCount = new AtomicInteger(0);
+        AtomicInteger ubCount = new AtomicInteger(0);
+
+        SieDocumentReader reader = new SieDocumentReader();
+        reader.setStreamValues(true);
+        reader.setIgnoreMissingOMFATTNING(true);
+        reader.getCallbacks().setIB(pv -> ibCount.incrementAndGet());
+        reader.getCallbacks().setUB(pv -> ubCount.incrementAndGet());
+        SieDocument doc = reader.readDocument(new File(url.getFile()).getAbsolutePath());
+
+        assertTrue(doc.getIB().isEmpty(), "IB should not be stored when streaming");
+        assertTrue(doc.getUB().isEmpty(), "UB should not be stored when streaming");
+        assertTrue(ibCount.get() > 0, "IB callback should have been called");
+        assertTrue(ubCount.get() > 0, "UB callback should have been called");
+    }
+
+    @Test
+    public void constructorWithParameters() throws IOException {
+        URL url = Thread.currentThread().getContextClassLoader().getResource("samples/1_BL0001_typ2.SE");
+        assertNotNull(url);
+
+        SieDocumentReader reader = new SieDocumentReader(false, true, false, true);
+        assertTrue(reader.isIgnoreMissingOMFATTNING());
+        assertTrue(reader.isThrowErrors());
+        assertFalse(reader.isIgnoreBTRANS());
+        assertFalse(reader.isStreamValues());
+
+        SieDocument doc = reader.readDocument(new File(url.getFile()).getAbsolutePath());
+        assertNotNull(doc);
+    }
+
+    @Test
+    public void invalidFileThrowsException(@TempDir Path tempDir) throws IOException {
+        Path badFile = tempDir.resolve("bad.SE");
+        Files.writeString(badFile, "This is not a SIE file\n");
+
+        SieDocumentReader reader = new SieDocumentReader();
+        reader.setThrowErrors(true);
+        assertThrows(SieInvalidFileException.class, () -> {
+            reader.readDocument(badFile.toString());
+        });
+    }
+
+    @Test
+    public void throwErrorsFalseCollectsExceptions(@TempDir Path tempDir) throws IOException {
+        Path badFile = tempDir.resolve("bad.SE");
+        Files.writeString(badFile, "This is not a SIE file\n");
+
+        SieDocumentReader reader = new SieDocumentReader();
+        reader.setThrowErrors(false);
+        List<Exception> collected = new ArrayList<>();
+        reader.getCallbacks().setSieException(collected::add);
+        SieDocument doc = reader.readDocument(badFile.toString());
+
+        assertNull(doc, "Should return null for invalid file");
+        assertFalse(collected.isEmpty(), "Exceptions should be collected");
+        assertInstanceOf(SieInvalidFileException.class, collected.get(0));
+    }
+
+    @Test
+    public void invalidDateHandledGracefully(@TempDir Path tempDir) throws IOException {
+        // Create a minimal SIE file with an invalid date (Feb 30)
+        String content = "#FLAGGA 0\n#SIETYP 4\n#PROGRAM \"Test\" 1.0\n#FORMAT PC8\n"
+                + "#GEN 20220230\n#FNAMN \"Test\"\n#KONTO 1000 \"Kassa\"\n#RAR 0 20220101 20221231\n";
+        Path sieFile = tempDir.resolve("invalid_date.SE");
+        Files.writeString(sieFile, content, Encoding.getCharset());
+
+        List<Exception> collected = new ArrayList<>();
+        SieDocumentReader reader = new SieDocumentReader();
+        reader.setThrowErrors(false);
+        reader.getCallbacks().setSieException(collected::add);
+        SieDocument doc = reader.readDocument(sieFile.toString());
+
+        // GEN date should be null due to invalid date
+        assertNull(doc.getGEN_DATE(), "Invalid date should result in null");
+        assertTrue(collected.stream().anyMatch(e -> e instanceof SieDateException),
+                "Should report a SieDateException for invalid date");
+    }
 }
diff --git a/src/test/java/alipsa/sieparser/TestSieDocument.java b/src/test/java/alipsa/sieparser/TestSieDocument.java
index 02ef44a..73cd881 100644
--- a/src/test/java/alipsa/sieparser/TestSieDocument.java
+++ b/src/test/java/alipsa/sieparser/TestSieDocument.java
@@ -162,7 +162,7 @@ private SieDocument readDocument(String fileName, boolean ignoreOMFATTN) {
             assertTrue(file.exists(), "SIE file not found at " + file.getAbsolutePath());
             SieDocumentReader reader = new SieDocumentReader();
             if (ignoreOMFATTN) {
-                reader.ignoreMissingOMFATTNING = true;
+                reader.setIgnoreMissingOMFATTNING(true);
             }
             doc = reader.readDocument(file.getAbsolutePath());
             if (reader.getValidationExceptions().size() > 0) {