JsonValue.java

/*******************************************************************************
 * Copyright (c) 2012-2016 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.everrest.core.impl.provider.json;

import java.util.Collections;
import java.util.Iterator;

public abstract class JsonValue {

    /** @return true if value is 'object', false otherwise. Should be overridden. */
    public boolean isObject() {
        return false;
    }

    /** @return true if value is 'array', false otherwise. Should be overridden. */
    public boolean isArray() {
        return false;
    }

    /** @return true if value is 'numeric', false otherwise. Should be overridden. */
    public boolean isNumeric() {
        return false;
    }

    /** @return true if value is 'long', false otherwise. Should be overridden. */
    public boolean isLong() {
        return false;
    }

    /** @return true if value is 'double', false otherwise. Should be overridden. */
    public boolean isDouble() {
        return false;
    }

    /** @return true if value is 'String', false otherwise. Should be overridden. */
    public boolean isString() {
        return false;
    }

    /** @return true if value is 'boolean', false otherwise. Should be overridden. */
    public boolean isBoolean() {
        return false;
    }

    /** @return true if value is 'null', false otherwise. Should be overridden. */
    public boolean isNull() {
        return false;
    }

    /**
     * Add child value. This method must be used if isArray() gives true.
     *
     * @param child
     *         the child value.
     */
    public void addElement(JsonValue child) {
        throw new UnsupportedOperationException("This type of JsonValue can't have child.");
    }

    /**
     * Add child value. This method must be used if isObject() gives true.
     *
     * @param key
     *         the key.
     * @param child
     *         the child value.
     */
    public void addElement(String key, JsonValue child) {
        throw new UnsupportedOperationException("This type of JsonValue can't have child.");
    }

    /**
     * Get all element of this value.
     *
     * @return Iterator.
     */
    public Iterator<JsonValue> getElements() {
        return Collections.<JsonValue>emptyList().iterator();
    }

    /**
     * Get all keys for access values.
     *
     * @return Iterator.
     */
    public Iterator<String> getKeys() {
        return Collections.<String>emptyList().iterator();
    }

    /**
     * Get value by key.
     *
     * @param key
     *         the key.
     * @return JsonValue with specified key.
     */
    public JsonValue getElement(String key) {
        return null;
    }

    /** @return number of child elements. */
    public int size() {
        return 0;
    }

    /** @return string value. Should be overridden. */
    public String getStringValue() {
        return null;
    }

    /** @return boolean value. Should be overridden. */
    public boolean getBooleanValue() {
        return false;
    }

    /** @return Number value. Should be overridden. */
    public Number getNumberValue() {
        return getDoubleValue();
    }

    /** @return byte value. Should be overridden. */
    public byte getByteValue() {
        return 0;
    }

    /** @return short Value. Should be overridden. */
    public short getShortValue() {
        return 0;
    }

    /** @return int value. Should be overridden. */
    public int getIntValue() {
        return 0;
    }

    /** @return long value. Should be overridden. */
    public long getLongValue() {
        return 0L;
    }

    /** @return float value. Should be overridden. */
    public float getFloatValue() {
        return 0.0F;
    }

    /** @return double value. Should be overridden. */
    public double getDoubleValue() {
        return 0.0;
    }

    @Override
    public abstract String toString();

    /**
     * Write value in given writer.
     *
     * @param writer
     *         Writer.
     * @throws JsonException
     *         if any errors occurs.
     */
    public abstract void writeTo(JsonWriter writer) throws JsonException;
}