source: josm/trunk/src/javax/json/EmptyObject.java@ 13949

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package javax.json;

import java.io.Serializable;
import java.util.AbstractMap;
import java.util.Collections;
import java.util.Set;

/**
 * Private implementation of immutable {@link JsonObject}.
 *
 * @author Lukas Jungmann
 */
final class EmptyObject extends AbstractMap<String, JsonValue> implements JsonObject, Serializable {

    private static final long serialVersionUID = -1461653546889072583L;

    @Override
    public Set<Entry<String, JsonValue>> entrySet() {
        return Collections.<Entry<String, JsonValue>>emptySet();
    }

    @Override
    public JsonArray getJsonArray(String name) {
        return (JsonArray) get(name);
    }

    @Override
    public JsonObject getJsonObject(String name) {
        return (JsonObject) get(name);
    }

    @Override
    public JsonNumber getJsonNumber(String name) {
        return (JsonNumber) get(name);
    }

    @Override
    public JsonString getJsonString(String name) {
        return (JsonString) get(name);
    }

    @Override
    public String getString(String name) {
        return getJsonString(name).getString();
    }

    @Override
    public String getString(String name, String defaultValue) {
        return defaultValue;
    }

    @Override
    public int getInt(String name) {
        return getJsonNumber(name).intValue();
    }

    @Override
    public int getInt(String name, int defaultValue) {
        return defaultValue;
    }

    @Override
    public boolean getBoolean(String name) {
        throw new NullPointerException();
    }

    @Override
    public boolean getBoolean(String name, boolean defaultValue) {
        return defaultValue;
    }

    @Override
    public boolean isNull(String name) {
        throw new NullPointerException();
    }

    @Override
    public ValueType getValueType() {
        return ValueType.OBJECT;
    }

    // Preserves singleton property
    private Object readResolve() {
        return JsonValue.EMPTY_JSON_OBJECT;
    }
}