closes #9: Implement diffr.

Author: sarinagurung

diff/src/main/java/diffr/diff/Diffr.java

@@ -0,0 +1,71 @@
+package diffr.diff;
+
+import com.google.common.collect.Lists;
+import diffr.suffixtree.SuffixTree;
+import diffr.suffixtree.SuffixTree.Matcher;
+import diffr.suffixtree.SuffixTrees;
+import diffr.util.instruction.CopyInstruction;
+import diffr.util.instruction.InsertInstruction;
+import diffr.util.instruction.Instruction;
+
+import java.util.List;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Generates a list of {@link Instruction}s to transform original file into a new file.
+ *
+ * @author Sarina Gurung
+ * @author Jakub D Kozlowski
+ * @since 0.3
+ */
+public final class Diffr {
+
+    private final List<String> originalFile;
+
+    private final List<String> newFile;
+
+    /**
+     * Default constructor.
+     *
+     * @param originalFile original file to be transform.
+     * @param newFile      new file to transform {@code originalFile} to.
+     *
+     * @throws NullPointerException if any parameter is null.
+     */
+    public Diffr(final List<String> originalFile, final List<String> newFile) {
+        this.originalFile = checkNotNull(originalFile);
+        this.newFile = checkNotNull(newFile);
+    }
+
+    /**
+     * Gets the list of {@link Instruction}s to transform {@code originalFile} to {@code newFile}.
+     *
+     * @return list of {@link Instruction}s.
+     */
+    public List<Instruction> diff() {
+
+        final List<Instruction> instructions = Lists.newArrayList();
+        final SuffixTree<String> suffixTree = SuffixTrees.newSuffixTree(this.originalFile);
+
+        Matcher<String> matcher = suffixTree.matcher();
+
+        for (final String newFileLine : newFile) {
+
+            if (!matcher.matchNext(newFileLine).isMatched()) {
+                if (!matcher.isRoot()) {
+                    instructions.add(new CopyInstruction(matcher.range()));
+                }
+                instructions.add(new InsertInstruction(newFileLine));
+                matcher = suffixTree.matcher();
+            }
+        }
+
+        if (!matcher.isRoot()) {
+            instructions.add(new CopyInstruction(matcher.range()));
+        }
+
+        return instructions;
+    }
+
+}

diff/src/main/java/diffr/diff/Main.java

@@ -1,5 +1,14 @@
 package diffr.diff;
 
+import com.google.common.io.Files;
+import diffr.util.instruction.Instruction;
+import diffr.util.instruction.InstructionComposer;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.util.List;
+
 /**
  * Main entry point to diffr's DIFF tool.
  *
@@ -12,6 +21,7 @@
  * </p>
  *
  * @author Jakub D Kozlowski
+ * @author Sarina Gurung
  * @since 0.1
  */
 public final class Main {
@@ -20,21 +30,51 @@ public final class Main {
      * Prints the usage of this tool.
      */
     private static void printUsage() {
-        System.out.println("diffr-diff <original-file> <new-file>");
+        System.out.println("Usage: diffr <original-file> <new-file>");
     }
 
     /**
      * Runs the diff tool on two files.
      *
      * @param args arguments to this tool.
      */
-    public static void main(String... args) {
+    public static void main(String... args) throws IOException {
 
-        if (args.length != 2) {
-            printUsage();
-            System.exit(-1);
-        }
+        try {
+
+            if (args.length != 2) {
+                printUsage();
+                System.exit(-1);
+            }
+
+            final File firstFile = new File(args[0]);
+            final File secondFile = new File(args[1]);
+
+            if (!firstFile.exists()) {
+                System.err.println("File " + firstFile + " not found.");
+                System.exit(-1);
+            }
 
-        System.exit(0);
+            if (!secondFile.exists()) {
+                System.err.println("File " + secondFile + " not found.");
+                System.exit(-1);
+            }
+
+            final List<String> originalFile = Files.readLines(firstFile, Charset.defaultCharset());
+            final List<String> newFile = Files.readLines(secondFile, Charset.defaultCharset());
+
+            final List<Instruction> instructions = new Diffr(originalFile, newFile).diff();
+
+            for (final Instruction instruction : instructions) {
+                System.out.println(InstructionComposer.composeString(instruction));
+            }
+            
+            System.out.flush();
+
+            System.exit(0);
+        }
+        catch (final IOException io) {
+            System.err.println("There was a problem reading the files: " + io);
+        }
     }
 }

diff/src/test/java/diffr/diff/DiffrTest.java

@@ -0,0 +1,95 @@
+package diffr.diff;
+
+import com.google.common.collect.Lists;
+import com.google.common.io.Files;
+import com.google.common.io.LineProcessor;
+import com.google.common.io.Resources;
+import diffr.util.instruction.Instruction;
+import diffr.util.instruction.InstructionComposer;
+import diffr.util.instruction.InstructionParser;
+import org.testng.annotations.DataProvider;
+import org.testng.annotations.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.charset.Charset;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+
+/**
+ * Tests {@link Diffr}.
+ *
+ * @author Sarina Gurung
+ * @author Jakub D Kozlowski
+ * @since 0.3
+ */
+public class DiffrTest {
+
+    private static final String DEFAULT_PROVIDER = "default-provider";
+
+    @DataProvider(name = "default-provider")
+    public Object[][] getFiles() throws URISyntaxException, IOException {
+
+        final List<Object[]> files = Lists.newArrayList();
+
+        final File originalDir = new File(Resources.getResource("original").toURI());
+        for (final File originalFile : originalDir.listFiles()) {
+            final File newFile = new File(Resources.getResource("new/" + originalFile.getName()).toURI());
+            final File patchFile = new File(Resources.getResource("patch/" + originalFile.getName()).toURI());
+            files.add(new Object[]{
+                    Files.readLines(originalFile, Charset.defaultCharset()),
+                    Files.readLines(newFile, Charset.defaultCharset()),
+                    Files.readLines(patchFile, Charset.defaultCharset(), new LineProcessor<List<Instruction>>() {
+
+                        private List<Instruction> instructions = Lists.newArrayList();
+
+                        @Override
+                        public boolean processLine(String s) throws IOException {
+                            instructions.add(InstructionParser.parseInstruction(s).get());
+                            return true;
+                        }
+
+                        @Override
+                        public List<Instruction> getResult() {
+                            return instructions;
+                        }
+                    })
+            });
+        }
+
+        return files.toArray(new Object[][]{});
+    }
+
+    @Test(expectedExceptions = NullPointerException.class)
+    public void testConstructorNullOriginalFile() {
+        new Diffr(null, Collections.EMPTY_LIST);
+    }
+
+    @Test(expectedExceptions = NullPointerException.class)
+    public void testConstructorNullNewFile() {
+        new Diffr(Collections.EMPTY_LIST, null);
+    }
+
+    @Test(dataProvider = DEFAULT_PROVIDER)
+    public void testDiff(final List<String> originalFile,
+                          final List<String> newFile,
+                          final List<Instruction> patchFile)
+            throws IOException, URISyntaxException {
+
+
+        final Diffr d = new Diffr(originalFile, newFile);
+
+        final Iterator<Instruction> actualInstructions = d.diff().iterator();
+
+        for (final Instruction expected : patchFile) {
+            final Instruction actual = actualInstructions.next();
+            assertThat(InstructionComposer.composeString(actual),
+                       is(InstructionComposer.composeString(expected)));
+        }
+    }
+}

diff/src/test/resources/new/test1

@@ -0,0 +1,5 @@
+One
+Two
+Three
+Five
+Seven

diff/src/test/resources/new/test2

@@ -0,0 +1,7 @@
+One
+Two
+Three
+Five
+Seven
+Eight
+Nine

diff/src/test/resources/new/test3

@@ -0,0 +1,8 @@
+One
+Two
+Three
+Five
+Seven
+Eight
+Nine
+Ten

diff/src/test/resources/new/test4

@@ -0,0 +1,10 @@
+One
+Two
+Three
+Five
+Seven
+Eight
+Nine
+Ten
+Twelve
+Thirteen

diff/src/test/resources/new/test5

@@ -0,0 +1,11 @@
+One
+Two
+Three
+Five
+Seven
+Eight
+Nine
+Ten
+Twelve
+Thirteen
+Fifteen

diff/src/test/resources/new/test6

@@ -0,0 +1 @@
+Hi

diff/src/test/resources/new/test7

@@ -0,0 +1 @@
+Hi

diff/src/test/resources/new/test9

@@ -0,0 +1,7 @@
+January
+February
+March
+
+April
+May
+June

diff/src/test/resources/original/test1

@@ -0,0 +1,5 @@
+One
+Two
+Three
+Four
+Six

diff/src/test/resources/original/test2

@@ -0,0 +1,7 @@
+One
+Two
+Three
+Four
+Six
+Eight
+Nine

diff/src/test/resources/original/test3

@@ -0,0 +1,8 @@
+Some other line
+Two
+Three
+Four
+Six
+Eight
+Nine
+Elevan

diff/src/test/resources/original/test4

@@ -0,0 +1,10 @@
+One
+Two
+Three
+Four
+Six
+Eight
+Nine
+Elevan
+Twelve
+Thirteen

diff/src/test/resources/original/test5

@@ -0,0 +1,11 @@
+One
+Two
+Three
+Four
+Six
+Eight
+Nine
+Elevan
+Twelve
+Thirteen
+Fourteen

diff/src/test/resources/original/test6

@@ -0,0 +1 @@
+Hello

diff/src/test/resources/original/test7

@@ -0,0 +1 @@
+Hi

diff/src/test/resources/original/test9

@@ -0,0 +1,7 @@
+April
+May
+June
+
+April
+May
+June

diff/src/test/resources/patch/test1

@@ -0,0 +1,3 @@
+0,2
+> Five
+> Seven

diff/src/test/resources/patch/test2

@@ -0,0 +1,4 @@
+0,2
+> Five
+> Seven
+5,6

diff/src/test/resources/patch/test3

@@ -0,0 +1,6 @@
+> One
+1,2
+> Five
+> Seven
+5,6
+> Ten