Java tutorial
/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 2011-2017 Oracle and/or its affiliates. All rights reserved. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common Development * and Distribution License("CDDL") (collectively, the "License"). You * may not use this file except in compliance with the License. You can * obtain a copy of the License at * https://oss.oracle.com/licenses/CDDL+GPL-1.1 * or LICENSE.txt. See the License for the specific * language governing permissions and limitations under the License. * * When distributing the software, include this License Header Notice in each * file and include the License file at LICENSE.txt. * * GPL Classpath Exception: * Oracle designates this particular file as subject to the "Classpath" * exception as provided by Oracle in the GPL Version 2 section of the License * file that accompanied this code. * * Modifications: * If applicable, add the following below the License Header, with the fields * enclosed by brackets [] replaced by your own identifying information: * "Portions Copyright [year] [name of copyright owner]" * * Contributor(s): * If you wish your version of this file to be governed by only the CDDL or * only the GPL Version 2, indicate your decision by adding "[Contributor] * elects to include this software in this distribution under the [CDDL or GPL * Version 2] license." If you don't indicate a single choice of license, a * recipient has the option to distribute your version of this file under * either the CDDL, the GPL Version 2 or to extend the choice of license to * its licensees as provided above. However, if you add GPL Version 2 code * and therefore, elected the GPL Version 2 license, then the option applies * only if the new code is made subject to such option by the copyright * holder. */ package javax.json; /** * <code>JsonValue</code> represents an immutable JSON value. * * * <p>A JSON value is one of the following: * an object ({@link JsonObject}), an array ({@link JsonArray}), * a number ({@link JsonNumber}), a string ({@link JsonString}), * {@code true} ({@link JsonValue#TRUE JsonValue.TRUE}), {@code false} * ({@link JsonValue#FALSE JsonValue.FALSE}), * or {@code null} ({@link JsonValue#NULL JsonValue.NULL}). */ public interface JsonValue { /** * The empty JSON object. * * @since 1.1 */ static final JsonObject EMPTY_JSON_OBJECT = new EmptyObject(); /** * The empty JSON array. * * @since 1.1 */ static final JsonArray EMPTY_JSON_ARRAY = new EmptyArray(); /** * Indicates the type of a {@link JsonValue} object. */ enum ValueType { /** * JSON array. */ ARRAY, /** * JSON object. */ OBJECT, /** * JSON string. */ STRING, /** * JSON number. */ NUMBER, /** * JSON true. */ TRUE, /** * JSON false. */ FALSE, /** * JSON null. */ NULL } /** * JSON null value. */ static final JsonValue NULL = new JsonValueImpl(ValueType.NULL); /** * JSON true value. */ static final JsonValue TRUE = new JsonValueImpl(ValueType.TRUE); /** * JSON false value. */ static final JsonValue FALSE = new JsonValueImpl(ValueType.FALSE); /** * Returns the value type of this JSON value. * * @return JSON value type */ ValueType getValueType(); /** * Return the JsonValue as a JsonObject * * @return the JsonValue as a JsonObject * @throws ClassCastException if the JsonValue is not a JsonObject * * @since 1.1 */ default JsonObject asJsonObject() { return JsonObject.class.cast(this); } /** * Return the JsonValue as a JsonArray * * @return the JsonValue as a JsonArray * @throws ClassCastException if the JsonValue is not a JsonArray * * @since 1.1 */ default JsonArray asJsonArray() { return JsonArray.class.cast(this); } /** * Returns JSON text for this JSON value. * * @return JSON text */ @Override String toString(); }