Moves zipkin-core language level to JRE 6 (#1245)

This is an api compatible change to allow code sharing between zipkin server and instrumentation, and without having to publish 2 jar files. We accidentally broke the ability to make agent-based instrumentation by compiling our model classes against Java 7 bytecode. Particularly, this causes a regression in Brave. To move back to Java 6 bytecode, we had to do a few things: * replace moshi internal dependency with gson, which is java 6 compliant * remove okio dependency and copy its Base64 class * incidentally a class it also copied! * do variable-size buffer writes w/ OutputBuffer instead of okio * fix a few nags about diamond ops etc.
openzipkin · Aug 18, 2016 · a17f260 · a17f260
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diff --git a/README.md b/README.md
@@ -24,9 +24,9 @@ Once you've started, browse to http://your_host:9411 to find traces!
 Check out the [`zipkin-server`](/zipkin-server) documentation for configuration details, or [`docker-zipkin`](https://github.com/openzipkin/docker-zipkin) for how to use docker-compose.
 
 ## Core Library
-The [core library](https://github.com/openzipkin/zipkin/tree/master/zipkin/src/main/java/io/zipkin) requires minimum language level 7. While currently only used by the server, we expect this library to be used in native instrumentation as well.
+The [core library](https://github.com/openzipkin/zipkin/tree/master/zipkin/src/main/java/io/zipkin) is used by both Zipkin instrumentation and the Zipkin server. Its minimum Java language level is 6, in efforts to support those writing agent instrumentation.
 
-This includes built-in codec for both thrift and json structs. Direct dependencies on thrift or moshi (json library) are avoided by minifying and repackaging classes used. The result is a 190k jar which won't conflict with any library you use.
+This includes built-in codec for both thrift and json structs. A direct dependency on gson (json library) is avoided by minifying and repackaging classes used. The result is a 155k jar which won't conflict with any library you use.
 
 Ex.
 ```java

diff --git a/pom.xml b/pom.xml
@@ -51,7 +51,6 @@
 
     <brave.version>3.9.0</brave.version>
     <cassandra-driver-core.version>3.1.0</cassandra-driver-core.version>
-    <moshi.version>1.2.0</moshi.version>
     <okio.version>1.9.0</okio.version>
     <jooq.version>3.8.4</jooq.version>
     <spring-boot.version>1.4.0.RELEASE</spring-boot.version>
@@ -275,12 +274,6 @@
       </dependency>
       <!-- End spring-boot-dependencies overrides -->
 
-      <dependency>
-        <groupId>com.squareup.moshi</groupId>
-        <artifactId>moshi</artifactId>
-        <version>${moshi.version}</version>
-      </dependency>
-
       <dependency>
         <groupId>com.squareup.okhttp3</groupId>
         <artifactId>okhttp</artifactId>

diff --git a/zipkin/pom.xml b/zipkin/pom.xml
@@ -28,17 +28,21 @@
 
   <properties>
     <main.basedir>${project.basedir}/..</main.basedir>
+    <main.java.version>1.6</main.java.version>
+    <main.signature.artifact>java16</main.signature.artifact>
   </properties>
 
   <dependencies>
     <dependency>
-      <groupId>com.squareup.okio</groupId>
-      <artifactId>okio</artifactId>
+      <groupId>com.google.code.gson</groupId>
+      <artifactId>gson</artifactId>
+      <version>2.7</version>
     </dependency>
 
     <dependency>
-      <groupId>com.squareup.moshi</groupId>
-      <artifactId>moshi</artifactId>
+      <groupId>com.squareup.okio</groupId>
+      <artifactId>okio</artifactId>
+      <scope>test</scope>
     </dependency>
 
     <dependency>
@@ -73,17 +77,13 @@
               <minimizeJar>true</minimizeJar>
               <filters>
                 <filter>
-                  <artifact>com.squareup.moshi:moshi</artifact>
+                  <artifact>com.google.code.gson:gson</artifact>
                   <includes>
-                    <include>com/squareup/moshi/BufferedSinkJsonWriter*</include>
-                    <include>com/squareup/moshi/BufferedSourceJsonReader*</include>
-                    <!-- don't get zipkin/internal/moshi/JsonAdapter$Factory.class -->
-                    <include>com/squareup/moshi/JsonAdapter.class</include>
-                    <include>com/squareup/moshi/JsonAdapter$?.class</include>
-                    <include>com/squareup/moshi/JsonDataException*</include>
-                    <include>com/squareup/moshi/JsonReader*</include>
-                    <include>com/squareup/moshi/JsonScope*</include>
-                    <include>com/squareup/moshi/JsonWriter*</include>
+                    <include>com/google/gson/stream/JsonReader*.class</include>
+                    <include>com/google/gson/stream/JsonToken.class</include>
+                    <include>com/google/gson/stream/JsonWriter.class</include>
+                    <include>com/google/gson/stream/MalformedJsonException.class</include>
+                    <include>com/google/gson/internal/JsonReaderInternalAccess.class</include>
                   </includes>
                 </filter>
                 <filter>
@@ -96,20 +96,15 @@
               </filters>
               <relocations>
                 <relocation>
-                  <pattern>okio</pattern>
-                  <shadedPattern>zipkin.internal.okio</shadedPattern>
-                </relocation>
-                <relocation>
-                  <pattern>com.squareup.moshi</pattern>
-                  <shadedPattern>zipkin.internal.moshi</shadedPattern>
+                  <pattern>com.google.gson</pattern>
+                  <shadedPattern>zipkin.internal.gson</shadedPattern>
                 </relocation>
               </relocations>
             </configuration>
           </execution>
         </executions>
       </plugin>
       <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-jar-plugin</artifactId>
         <executions>
           <execution>

diff --git a/zipkin/src/main/java/zipkin/Annotation.java b/zipkin/src/main/java/zipkin/Annotation.java
@@ -13,7 +13,6 @@
  */
 package zipkin;
 
-import zipkin.internal.JsonCodec;
 import zipkin.internal.Nullable;
 
 import static zipkin.internal.Util.checkNotNull;
@@ -100,11 +99,6 @@ public Annotation build() {
     }
   }
 
-  @Override
-  public String toString() {
-    return JsonCodec.ANNOTATION_ADAPTER.toJson(this);
-  }
-
   @Override
   public boolean equals(Object o) {
     if (o == this) {
@@ -135,7 +129,7 @@ public int hashCode() {
   @Override
   public int compareTo(Annotation that) {
     if (this == that) return 0;
-    int byTimestamp = Long.compare(timestamp, that.timestamp);
+    int byTimestamp = timestamp < that.timestamp ? -1 : timestamp == that.timestamp ? 0 : 1;
     if (byTimestamp != 0) return byTimestamp;
     return value.compareTo(that.value);
   }

diff --git a/zipkin/src/main/java/zipkin/BinaryAnnotation.java b/zipkin/src/main/java/zipkin/BinaryAnnotation.java
@@ -14,7 +14,6 @@
 package zipkin;
 
 import java.util.Arrays;
-import zipkin.internal.JsonCodec;
 import zipkin.internal.Nullable;
 import zipkin.internal.Util;
 
@@ -196,11 +195,6 @@ public BinaryAnnotation build() {
     }
   }
 
-  @Override
-  public String toString() {
-    return JsonCodec.BINARY_ANNOTATION_ADAPTER.toJson(this);
-  }
-
   @Override
   public boolean equals(Object o) {
     if (o == this) {

diff --git a/zipkin/src/main/java/zipkin/DependencyLink.java b/zipkin/src/main/java/zipkin/DependencyLink.java
@@ -16,8 +16,8 @@
 import java.io.ObjectStreamException;
 import java.io.Serializable;
 import java.io.StreamCorruptedException;
-import zipkin.internal.JsonCodec;
 
+import static zipkin.internal.Util.UTF_8;
 import static zipkin.internal.Util.checkNotNull;
 
 public final class DependencyLink implements Serializable {
@@ -86,7 +86,7 @@ public DependencyLink build() {
 
   @Override
   public String toString() {
-    return JsonCodec.DEPENDENCY_LINK_ADAPTER.toJson(this);
+    return new String(Codec.JSON.writeDependencyLink(this), UTF_8);
   }
 
   @Override

diff --git a/zipkin/src/main/java/zipkin/Endpoint.java b/zipkin/src/main/java/zipkin/Endpoint.java
@@ -15,7 +15,6 @@
 
 import java.util.Arrays;
 import java.util.Locale;
-import zipkin.internal.JsonCodec;
 import zipkin.internal.Nullable;
 import zipkin.internal.Util;
 
@@ -150,11 +149,6 @@ public Endpoint build() {
     }
   }
 
-  @Override
-  public String toString() {
-    return JsonCodec.ENDPOINT_ADAPTER.toJson(this);
-  }
-
   @Override
   public boolean equals(Object o) {
     if (o == this) {

diff --git a/zipkin/src/main/java/zipkin/Span.java b/zipkin/src/main/java/zipkin/Span.java
@@ -21,9 +21,9 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Set;
-import zipkin.internal.JsonCodec;
 import zipkin.internal.Nullable;
 
+import static zipkin.internal.Util.UTF_8;
 import static zipkin.internal.Util.checkNotNull;
 import static zipkin.internal.Util.equal;
 import static zipkin.internal.Util.sortedList;
@@ -273,14 +273,14 @@ public Builder duration(@Nullable Long duration) {
      * @see Span#annotations
      */
     public Builder annotations(Collection<Annotation> annotations) {
-      this.annotations = new HashSet<>(annotations);
+      this.annotations = new HashSet<Annotation>(annotations);
       return this;
     }
 
     /** @see Span#annotations */
     public Builder addAnnotation(Annotation annotation) {
       if (annotations == null) {
-        annotations = new HashSet<>();
+        annotations = new HashSet<Annotation>();
       }
       annotations.add(annotation);
       return this;
@@ -292,14 +292,14 @@ public Builder addAnnotation(Annotation annotation) {
      * @see Span#binaryAnnotations
      */
     public Builder binaryAnnotations(Collection<BinaryAnnotation> binaryAnnotations) {
-      this.binaryAnnotations = new HashSet<>(binaryAnnotations);
+      this.binaryAnnotations = new HashSet<BinaryAnnotation>(binaryAnnotations);
       return this;
     }
 
     /** @see Span#binaryAnnotations */
     public Builder addBinaryAnnotation(BinaryAnnotation binaryAnnotation) {
       if (binaryAnnotations == null) {
-        binaryAnnotations = new HashSet<>();
+        binaryAnnotations = new HashSet<BinaryAnnotation>();
       }
       binaryAnnotations.add(binaryAnnotation);
       return this;
@@ -318,7 +318,7 @@ public Span build() {
 
   @Override
   public String toString() {
-    return JsonCodec.SPAN_ADAPTER.toJson(this);
+    return new String(Codec.JSON.writeSpan(this), UTF_8);
   }
 
   @Override
@@ -369,9 +369,9 @@ public int hashCode() {
   @Override
   public int compareTo(Span that) {
     if (this == that) return 0;
-    int byTimestamp = Long.compare(
-        this.timestamp == null ? Long.MIN_VALUE : this.timestamp,
-        that.timestamp == null ? Long.MIN_VALUE : that.timestamp);
+    long x = this.timestamp == null ? Long.MIN_VALUE : this.timestamp;
+    long y = that.timestamp == null ? Long.MIN_VALUE : that.timestamp;
+    int byTimestamp = x < y ? -1 : x == y ? 0 : 1;
     if (byTimestamp != 0) return byTimestamp;
     return this.name.compareTo(that.name);
   }
@@ -390,7 +390,7 @@ public String idString() {
 
   /** Returns the distinct {@link Endpoint#serviceName service names} that logged to this span. */
   public Set<String> serviceNames() {
-    Set<String> result = new HashSet<>();
+    Set<String> result = new HashSet<String>();
     for (Annotation a : annotations) {
       if (a.endpoint == null) continue;
       if (a.endpoint.serviceName.isEmpty()) continue;

diff --git a/zipkin/src/main/java/zipkin/collector/Collector.java b/zipkin/src/main/java/zipkin/collector/Collector.java
@@ -99,7 +99,7 @@ public void acceptSpans(byte[] serializedSpans, Codec codec, Callback<Void> call
   }
 
   public void acceptSpans(List<byte[]> serializedSpans, Codec codec, Callback<Void> callback) {
-    List<Span> spans = new ArrayList<>(serializedSpans.size());
+    List<Span> spans = new ArrayList<Span>(serializedSpans.size());
     try {
       int bytesRead = 0;
       for (byte[] serializedSpan : serializedSpans) {
@@ -137,7 +137,7 @@ public void accept(List<Span> spans, Callback<Void> callback) {
   }
 
   List<Span> sample(List<Span> input) {
-    List<Span> sampled = new ArrayList<>(input.size());
+    List<Span> sampled = new ArrayList<Span>(input.size());
     for (Span s : input) {
       if (sampler.isSampled(s)) sampled.add(s);
     }