craftinc-gates/src/org/mcteam/ancientgates/gson/JsonDeserializationVisitor.java
locutus c1a601ff32 built against CB 1000
Signed-off-by: locutus <bladedpenguin@gmail.com>
2011-07-22 23:00:34 -04:00

113 lines
3.8 KiB
Java

/*
* 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 org.mcteam.ancientgates.gson;
import java.lang.reflect.Type;
/**
* Abstract data value container for the {@link ObjectNavigator.Visitor}
* implementations. This class exposes the {@link #getTarget()} method
* which returns the class that was visited by this object.
*
* @author Inderjeet Singh
* @author Joel Leitch
*/
abstract class JsonDeserializationVisitor<T> implements ObjectNavigator.Visitor {
protected final ObjectNavigatorFactory factory;
protected final ObjectConstructor objectConstructor;
protected final ParameterizedTypeHandlerMap<JsonDeserializer<?>> deserializers;
protected T target;
protected final JsonElement json;
protected final Type targetType;
protected final JsonDeserializationContext context;
protected boolean constructed;
public JsonDeserializationVisitor(JsonElement json, Type targetType,
ObjectNavigatorFactory factory, ObjectConstructor objectConstructor,
ParameterizedTypeHandlerMap<JsonDeserializer<?>> deserializers,
JsonDeserializationContext context) {
Preconditions.checkNotNull(json);
this.targetType = targetType;
this.factory = factory;
this.objectConstructor = objectConstructor;
this.deserializers = deserializers;
this.json = json;
this.context = context;
this.constructed = false;
}
public T getTarget() {
if (!constructed) {
target = constructTarget();
constructed = true;
}
return target;
}
protected abstract T constructTarget();
public void start(ObjectTypePair node) {
}
public void end(ObjectTypePair node) {
}
@SuppressWarnings("unchecked")
public final boolean visitUsingCustomHandler(ObjectTypePair objTypePair) {
Pair<JsonDeserializer<?>, ObjectTypePair> pair = objTypePair.getMatchingHandler(deserializers);
if (pair == null) {
return false;
}
Object value = invokeCustomDeserializer(json, pair);
target = (T) value;
constructed = true;
return true;
}
protected Object invokeCustomDeserializer(JsonElement element,
Pair<JsonDeserializer<?>, ObjectTypePair> pair) {
if (element == null || element.isJsonNull()) {
return null;
}
Type objType = pair.second.type;
return (pair.first).deserialize(element, objType, context);
}
final Object visitChildAsObject(Type childType, JsonElement jsonChild) {
JsonDeserializationVisitor<?> childVisitor =
new JsonObjectDeserializationVisitor<Object>(jsonChild, childType,
factory, objectConstructor, deserializers, context);
return visitChild(childType, childVisitor);
}
final Object visitChildAsArray(Type childType, JsonArray jsonChild) {
JsonDeserializationVisitor<?> childVisitor =
new JsonArrayDeserializationVisitor<Object>(jsonChild.getAsJsonArray(), childType,
factory, objectConstructor, deserializers, context);
return visitChild(childType, childVisitor);
}
private Object visitChild(Type type, JsonDeserializationVisitor<?> childVisitor) {
ObjectNavigator on = factory.create(new ObjectTypePair(null, type, false));
on.accept(childVisitor);
// the underlying object may have changed during the construction phase
// This happens primarily because of custom deserializers
return childVisitor.getTarget();
}
}