streamline rebased Gson into source; rebase was done to prevent conflict with other plugins (like upcoming WorldGuard release) which also use Gson; Bukkit doesn't yet handle such conflicts properly

src/com/bukkit/mcteam/gson/DelegatingJsonElementVisitor.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2008 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.bukkit.mcteam.gson;
+
+import java.io.IOException;
+
+/**
+ * A simple implementation of the {@link JsonElementVisitor} that simply delegates the method
+ * invocation onto a {@code delegate} instance of the {@link JsonElementVisitor}.  This object
+ * can be used to build a chain of visitors such that each Visitor instance can perform some
+ * operation on the {@link JsonElement} and then pass on the input to the delegate.  This kind
+ * of pattern is sometimes referred as a "Chain of Responsibility".
+ *
+ * <p>The following is an example use case:
+ *
+ * <pre>
+ * class JsonEscapingVisitor extends DelegatingJsonElementVisitor {
+ *   public JsonEscapingVisitor(JsonElementVisitor) {
+ *     super(visitor);
+ *   }
+ *
+ *   public void visitPrimitive(JsonPrimitive primitive) {
+ *     JsonPrimitive escapedPrimitive = escapePrimitiveObject(primitive);
+ *     super.visitPrimitive(escapedPrimitive);
+ *   }
+ * }
+ *
+ * JsonElementVisitor visitor = new JsonEscapingVisitor(new FormattingVisitor());
+ * </pre></p>
+ *
+ * @author Joel Leitch
+ */
+class DelegatingJsonElementVisitor implements JsonElementVisitor {
+  private final JsonElementVisitor delegate;
+
+  protected DelegatingJsonElementVisitor(JsonElementVisitor delegate) {
+    Preconditions.checkNotNull(delegate);
+    this.delegate = delegate;
+  }
+
+  public void endArray(JsonArray array) throws IOException {
+    delegate.endArray(array);
+  }
+
+  public void endObject(JsonObject object) throws IOException {
+    delegate.endObject(object);
+  }
+
+  public void startArray(JsonArray array) throws IOException {
+    delegate.startArray(array);
+  }
+
+  public void startObject(JsonObject object) throws IOException {
+    delegate.startObject(object);
+  }
+
+  public void visitArrayMember(JsonArray parent, JsonPrimitive member, 
+      boolean isFirst) throws IOException {
+    delegate.visitArrayMember(parent, member, isFirst);
+  }
+
+  public void visitArrayMember(JsonArray parent, JsonArray member, 
+      boolean isFirst) throws IOException {
+    delegate.visitArrayMember(parent, member, isFirst);
+  }
+
+  public void visitArrayMember(JsonArray parent, JsonObject member, 
+      boolean isFirst) throws IOException {
+    delegate.visitArrayMember(parent, member, isFirst);
+  }
+
+  public void visitObjectMember(JsonObject parent, String memberName, JsonPrimitive member, 
+      boolean isFirst) throws IOException {
+    delegate.visitObjectMember(parent, memberName, member, isFirst);
+  }
+
+  public void visitObjectMember(JsonObject parent, String memberName, JsonArray member, 
+      boolean isFirst) throws IOException {
+    delegate.visitObjectMember(parent, memberName, member, isFirst);
+  }
+
+  public void visitObjectMember(JsonObject parent, String memberName, JsonObject member, 
+      boolean isFirst) throws IOException {
+    delegate.visitObjectMember(parent, memberName, member, isFirst);
+  }
+
+  public void visitNullObjectMember(JsonObject parent, String memberName, 
+      boolean isFirst) throws IOException {
+    delegate.visitNullObjectMember(parent, memberName, isFirst);
+  }
+
+  public void visitPrimitive(JsonPrimitive primitive) throws IOException {
+    delegate.visitPrimitive(primitive);
+  }
+
+  public void visitNull() throws IOException {
+    delegate.visitNull();
+  }
+
+  public void visitNullArrayMember(JsonArray parent, boolean isFirst) throws IOException {
+    delegate.visitNullArrayMember(parent, isFirst);
+  }
+}