com.google.gwtjsonrpc.server.MapDeserializer.java Source code

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Here is the source code for com.google.gwtjsonrpc.server.MapDeserializer.java

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// Copyright 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.google.gwtjsonrpc.server;

import com.google.gson.InstanceCreator;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonNull;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.HashMap;
import java.util.Map;

public class MapDeserializer implements JsonDeserializer<Map<Object, Object>>, JsonSerializer<Map<Object, Object>>,
        InstanceCreator<Map<Object, Object>> {
    public Map<Object, Object> createInstance(final Type type) {
        return new HashMap<Object, Object>();
    }

    public Map<Object, Object> deserialize(final JsonElement json, final Type typeOfT,
            final JsonDeserializationContext context) throws JsonParseException {
        final Type kt = ((ParameterizedType) typeOfT).getActualTypeArguments()[0];
        final Type vt = ((ParameterizedType) typeOfT).getActualTypeArguments()[1];

        if (json.isJsonNull()) {
            return null;
        }

        if (kt == String.class) {
            if (!json.isJsonObject()) {
                throw new JsonParseException("Expected object for map type");
            }
            final JsonObject p = (JsonObject) json;
            final Map<Object, Object> r = createInstance(typeOfT);
            for (final Map.Entry<String, JsonElement> e : p.entrySet()) {
                final Object v = context.deserialize(e.getValue(), vt);
                r.put(e.getKey(), v);
            }
            return r;
        } else {
            if (!json.isJsonArray()) {
                throw new JsonParseException("Expected array for map type");
            }

            final JsonArray p = (JsonArray) json;
            final Map<Object, Object> r = createInstance(typeOfT);
            for (int n = 0; n < p.size();) {
                final Object k = context.deserialize(p.get(n++), kt);
                final Object v = context.deserialize(p.get(n++), vt);
                r.put(k, v);
            }
            return r;
        }
    }

    public JsonElement serialize(final Map<Object, Object> src, final Type typeOfSrc,
            final JsonSerializationContext context) {
        final Type kt = ((ParameterizedType) typeOfSrc).getActualTypeArguments()[0];
        final Type vt = ((ParameterizedType) typeOfSrc).getActualTypeArguments()[1];

        if (src == null) {
            return new JsonNull();
        }

        if (kt == String.class) {
            final JsonObject r = new JsonObject();
            for (final Map.Entry<Object, Object> e : src.entrySet()) {
                r.add(e.getKey().toString(), context.serialize(e.getValue(), vt));
            }
            return r;
        } else {
            final JsonArray r = new JsonArray();
            for (final Map.Entry<Object, Object> e : src.entrySet()) {
                r.add(context.serialize(e.getKey(), kt));
                r.add(context.serialize(e.getValue(), vt));
            }
            return r;
        }
    }
}