org.rapla.rest.client.gwt.internal.impl.ser.StringMapSerializer.java Source code

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Here is the source code for org.rapla.rest.client.gwt.internal.impl.ser.StringMapSerializer.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 org.rapla.rest.client.gwt.internal.impl.ser;

import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;

import javax.inject.Provider;

import org.rapla.rest.client.gwt.internal.impl.JsonSerializer;
import org.rapla.rest.client.gwt.internal.impl.ResultDeserializer;

import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.core.client.JsonUtils;

/**
 * Serialization for a {@link Map} using only String keys.
 * <p>
 * The JSON representation is a JSON object, the map keys become the property
 * names of the JSON object and the map values are the property values.
 * <p>
 * When deserialized from JSON the Map implementation is always a
 * {@link HashMap}. When serializing to JSON any Map is permitted.
 */
public class StringMapSerializer<V> extends JsonSerializer<Map<String, V>>
        implements ResultDeserializer<Map<String, V>> {
    private final Provider<JsonSerializer<V>> valueSerializer;

    public StringMapSerializer(final JsonSerializer<V> v) {
        valueSerializer = new SimpleGwtProvider<JsonSerializer<V>>(v);
    }

    public StringMapSerializer(final Provider<JsonSerializer<V>> v) {
        valueSerializer = v;
    }

    @Override
    public void printJson(final StringBuilder sb, final Map<String, V> o) {
        sb.append('{');
        boolean first = true;
        for (final Map.Entry<String, V> e : o.entrySet()) {
            if (first) {
                first = false;
            } else {
                sb.append(',');
            }
            sb.append(JsonUtils.escapeValue(e.getKey()));
            sb.append(':');
            encode(sb, valueSerializer.get(), e.getValue());
        }
        sb.append('}');
    }

    private static <T> void encode(final StringBuilder sb, final JsonSerializer<T> serializer, final T item) {
        if (item != null) {
            serializer.printJson(sb, item);
        } else {
            sb.append(JS_NULL);
        }
    }

    @Override
    public Map<String, V> fromJson(final Object o) {
        if (o == null) {
            return null;
        }

        final JavaScriptObject jso = (JavaScriptObject) o;
        final Map<String, V> r = new LinkedHashMap<String, V>();
        copy(r, jso);
        return r;
    }

    private native void copy(Map<String, V> r, JavaScriptObject jsObject)
    /*-{
      for (var key in jsObject) {
        this.@org.rapla.rest.client.gwt.internal.impl.ser.StringMapSerializer::copyOne(Ljava/util/Map;Ljava/lang/String;Ljava/lang/Object;)(r, key, jsObject[key]);
      }
    }-*/;

    void copyOne(final Map<String, V> r, final String k, final Object o) {
        r.put(k, valueSerializer.get().fromJson(o));
    }
}