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/MappedObjectConstructor.java

@@ -0,0 +1,112 @@
+/*
+ * 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.lang.reflect.AccessibleObject;
+import java.lang.reflect.Array;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Type;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * This class contains a mapping of all the application specific
+ * {@link InstanceCreator} instances.  Registering an {@link InstanceCreator}
+ * with this class will override the default object creation that is defined
+ * by the ObjectConstructor that this class is wrapping.  Using this class
+ * with the JSON framework provides the application with "pluggable" modules
+ * to customize framework to suit the application's needs.
+ *
+ * @author Joel Leitch
+ */
+final class MappedObjectConstructor implements ObjectConstructor {
+  private static final Logger log = Logger.getLogger(MappedObjectConstructor.class.getName());
+
+  private final ParameterizedTypeHandlerMap<InstanceCreator<?>> instanceCreatorMap;
+  
+  public MappedObjectConstructor(
+      ParameterizedTypeHandlerMap<InstanceCreator<?>> instanceCreators) {
+    instanceCreatorMap = instanceCreators;
+  }
+
+  @SuppressWarnings("unchecked")
+  public <T> T construct(Type typeOfT) {
+    InstanceCreator<T> creator = (InstanceCreator<T>) instanceCreatorMap.getHandlerFor(typeOfT);
+    if (creator != null) {
+      return creator.createInstance(typeOfT);
+    }
+    return (T) constructWithNoArgConstructor(typeOfT);
+  }
+
+  public Object constructArray(Type type, int length) {
+    return Array.newInstance(TypeUtils.toRawClass(type), length);
+  }
+
+  private <T> T constructWithNoArgConstructor(Type typeOfT) {
+    try {
+      Constructor<T> constructor = getNoArgsConstructor(typeOfT);
+      if (constructor == null) {
+        throw new RuntimeException(("No-args constructor for " + typeOfT + " does not exist. "
+            + "Register an InstanceCreator with Gson for this type to fix this problem."));
+      }
+      return constructor.newInstance();
+    } catch (InstantiationException e) {
+      throw new RuntimeException(("Unable to invoke no-args constructor for " + typeOfT + ". "
+          + "Register an InstanceCreator with Gson for this type may fix this problem."), e);
+    } catch (IllegalAccessException e) {
+      throw new RuntimeException(("Unable to invoke no-args constructor for " + typeOfT + ". "
+          + "Register an InstanceCreator with Gson for this type may fix this problem."), e);
+    } catch (InvocationTargetException e) {
+      throw new RuntimeException(("Unable to invoke no-args constructor for " + typeOfT + ". "
+          + "Register an InstanceCreator with Gson for this type may fix this problem."), e);
+    }
+  }
+
+  @SuppressWarnings({"unchecked", "cast"})
+  private <T> Constructor<T> getNoArgsConstructor(Type typeOfT) {
+    TypeInfo typeInfo = new TypeInfo(typeOfT);
+    Class<T> clazz = (Class<T>) typeInfo.getRawClass();
+    Constructor<T>[] declaredConstructors = (Constructor<T>[]) clazz.getDeclaredConstructors();
+    AccessibleObject.setAccessible(declaredConstructors, true);
+    for (Constructor<T> constructor : declaredConstructors) {
+      if (constructor.getParameterTypes().length == 0) {
+        return constructor;
+      }
+    }
+    return null;
+  }
+
+  /**
+   * Use this methods to register an {@link InstanceCreator} for a new type.
+   *
+   * @param <T> the type of class to be mapped with its "creator"
+   * @param typeOfT the instance type that will be created
+   * @param creator the {@link InstanceCreator} instance to register
+   */
+  <T> void register(Type typeOfT, InstanceCreator<? extends T> creator) {
+    if (instanceCreatorMap.hasSpecificHandlerFor(typeOfT)) {
+      log.log(Level.WARNING, "Overriding the existing InstanceCreator for {0}", typeOfT);
+    }
+    instanceCreatorMap.register(typeOfT, creator);
+  }
+  
+  @Override
+  public String toString() {
+    return instanceCreatorMap.toString();
+  }
+}