Source code

001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
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006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.json;
014
015import org.apache.juneau.*;
016import org.apache.juneau.annotation.*;
017import org.apache.juneau.parser.*;
018
019/**
020 * Parses any valid JSON text into a POJO model.
021 *
022 * <h5 class='topic'>Media types</h5>
023 *
024 * Handles <c>Content-Type</c> types:  <bc>application/json, text/json</bc>
025 *
026 * <h5 class='topic'>Description</h5>
027 *
028 * This parser uses a state machine, which makes it very fast and efficient.  It parses JSON in about 70% of the
029 * time that it takes the built-in Java DOM parsers to parse equivalent XML.
030 *
031 * <p>
032 * This parser handles all valid JSON syntax.
033 * In addition, when strict mode is disable, the parser also handles the following:
034 * <ul class='spaced-list'>
035 *    <li>
036 *       Javascript comments (both {@code /*} and {@code //}) are ignored.
037 *    <li>
038 *       Both single and double quoted strings.
039 *    <li>
040 *       Automatically joins concatenated strings (e.g. <code><js>"aaa"</js> + <js>'bbb'</js></code>).
041 *    <li>
042 *       Unquoted attributes.
043 * </ul>
044 *
045 * <p>
046 * Also handles negative, decimal, hexadecimal, octal, and double numbers, including exponential notation.
047 *
048 * <p>
049 * This parser handles the following input, and automatically returns the corresponding Java class.
050 * <ul class='spaced-list'>
051 *    <li>
052 *       JSON objects (<js>"{...}"</js>) are converted to {@link ObjectMap ObjectMaps}.
053 *       <b>Note:</b>  If a <code><xa>_type</xa>=<xs>'xxx'</xs></code> attribute is specified on the object, then an
054 *       attempt is made to convert the object to an instance of the specified Java bean class.
055 *       See the <c>beanTypeName</c> setting on the {@link PropertyStore} for more information about parsing
056 *       beans from JSON.
057 *    <li>
058 *       JSON arrays (<js>"[...]"</js>) are converted to {@link ObjectList ObjectLists}.
059 *    <li>
060 *       JSON string literals (<js>"'xyz'"</js>) are converted to {@link String Strings}.
061 *    <li>
062 *       JSON numbers (<js>"123"</js>, including octal/hexadecimal/exponential notation) are converted to
063 *       {@link Integer Integers}, {@link Long Longs}, {@link Float Floats}, or {@link Double Doubles} depending on
064 *       whether the number is decimal, and the size of the number.
065 *    <li>
066 *       JSON booleans (<js>"false"</js>) are converted to {@link Boolean Booleans}.
067 *    <li>
068 *       JSON nulls (<js>"null"</js>) are converted to <jk>null</jk>.
069 *    <li>
070 *       Input consisting of only whitespace or JSON comments are converted to <jk>null</jk>.
071 * </ul>
072 *
073 * <p>
074 * Input can be any of the following:
075 * <ul class='spaced-list'>
076 *    <li>
077 *       <js>"{...}"</js> - Converted to a {@link ObjectMap} or an instance of a Java bean if a <xa>_type</xa>
078 *       attribute is present.
079 *    <li>
080 *       <js>"[...]"</js> - Converted to a {@link ObjectList}.
081 *    <li>
082 *       <js>"123..."</js> - Converted to a {@link Number} (either {@link Integer}, {@link Long}, {@link Float},
083 *       or {@link Double}).
084 *    <li>
085 *       <js>"true"</js>/<js>"false"</js> - Converted to a {@link Boolean}.
086 *    <li>
087 *       <js>"null"</js> - Returns <jk>null</jk>.
088 *    <li>
089 *       <js>"'xxx'"</js> - Converted to a {@link String}.
090 *    <li>
091 *       <js>"\"xxx\""</js> - Converted to a {@link String}.
092 *    <li>
093 *       <js>"'xxx' + \"yyy\""</js> - Converted to a concatenated {@link String}.
094 * </ul>
095 *
096 * <p>
097 * TIP:  If you know you're parsing a JSON object or array, it can be easier to parse it using the
098 * {@link ObjectMap#ObjectMap(CharSequence) ObjectMap(CharSequence)} or {@link ObjectList#ObjectList(CharSequence)
099 * ObjectList(CharSequence)} constructors instead of using this class.
100 * The end result should be the same.
101 */
102@ConfigurableContext
103public class JsonParser extends ReaderParser {
104
105   //-------------------------------------------------------------------------------------------------------------------
106   // Configurable properties
107   //-------------------------------------------------------------------------------------------------------------------
108
109   static final String PREFIX = "JsonParser";
110
111   /**
112    * Configuration property:  Validate end.
113    *
114    * <h5 class='section'>Property:</h5>
115    * <ul>
116    *    <li><b>Name:</b>  <js>"JsonParser.validateEnd.b"</js>
117    *    <li><b>Data type:</b>  <c>Boolean</c>
118    *    <li><b>Default:</b>  <jk>false</jk>
119    *    <li><b>Session property:</b>  <jk>false</jk>
120    *    <li><b>Methods:</b>
121    *       <ul>
122    *          <li class='jm'>{@link JsonParserBuilder#validateEnd(boolean)}
123    *          <li class='jm'>{@link JsonParserBuilder#validateEnd()}
124    *       </ul>
125    * </ul>
126    *
127    * <h5 class='section'>Description:</h5>
128    * <p>
129    * If <jk>true</jk>, after parsing a POJO from the input, verifies that the remaining input in
130    * the stream consists of only comments or whitespace.
131    *
132    * <h5 class='section'>Example:</h5>
133    * <p class='bcode w800'>
134    *    <jc>// Create a parser that validates that there's no garbage at the end of the input.</jc>
135    *    ReaderParser p = JsonParser.
136    *       .<jsm>create</jsm>()
137    *       .validateEnd()
138    *       .build();
139    *
140    *    <jc>// Same, but use property.</jc>
141    *    ReaderParser p = JsonParser.
142    *       .<jsm>create</jsm>()
143    *       .set(<jsf>JSON_validateEnd</jsf>, <jk>true</jk>)
144    *       .build();
145    *
146    *    <jc>// Should fail because input has multiple POJOs.</jc>
147    *    String in = <js>"{foo:'bar'}{baz:'qux'}"</js>;
148    *    MyBean myBean = p.parse(in, MyBean.<jk>class</jk>);
149    * </p>
150    */
151   public static final String JSON_validateEnd = PREFIX + ".validateEnd.b";
152
153   //-------------------------------------------------------------------------------------------------------------------
154   // Predefined instances
155   //-------------------------------------------------------------------------------------------------------------------
156
157   /** Default parser, all default settings.*/
158   public static final JsonParser DEFAULT = new JsonParser.Simple(PropertyStore.DEFAULT);
159
160   /** Default parser, all default settings.*/
161   public static final JsonParser DEFAULT_STRICT = new JsonParser.Strict(PropertyStore.DEFAULT);
162
163
164   //-------------------------------------------------------------------------------------------------------------------
165   // Predefined subclasses
166   //-------------------------------------------------------------------------------------------------------------------
167
168   /** Default parser, strict mode. */
169   public static class Strict extends JsonParser {
170
171      /**
172       * Constructor.
173       *
174       * @param ps The property store containing all the settings for this object.
175       */
176      public Strict(PropertyStore ps) {
177         super(ps.builder().set(PARSER_strict, true).set(JSON_validateEnd, true).build());
178      }
179   }
180
181   /** Default parser, simple mode. */
182   public static class Simple extends JsonParser {
183
184      /**
185       * Constructor.
186       *
187       * @param ps The property store containing all the settings for this object.
188       */
189      public Simple(PropertyStore ps) {
190         super(ps, "application/json+simple", "text/json+simple");
191      }
192   }
193
194   //-------------------------------------------------------------------------------------------------------------------
195   // Instance
196   //-------------------------------------------------------------------------------------------------------------------
197
198   private final boolean validateEnd;
199
200   /**
201    * Constructor.
202    *
203    * @param ps The property store containing all the settings for this object.
204    */
205   public JsonParser(PropertyStore ps) {
206      this(ps, "application/json", "text/json");
207   }
208
209   /**
210    * Constructor.
211    *
212    * @param ps The property store containing all the settings for this object.
213    * @param consumes The list of media types that this parser consumes (e.g. <js>"application/json"</js>).
214    */
215   public JsonParser(PropertyStore ps, String...consumes) {
216      super(ps, consumes);
217      validateEnd = getBooleanProperty(JSON_validateEnd, false);
218   }
219
220   @Override /* Context */
221   public JsonParserBuilder builder() {
222      return new JsonParserBuilder(getPropertyStore());
223   }
224
225   /**
226    * Instantiates a new clean-slate {@link JsonParserBuilder} object.
227    *
228    * <p>
229    * This is equivalent to simply calling <code><jk>new</jk> JsonParserBuilder()</code>.
230    *
231    * <p>
232    * Note that this method creates a builder initialized to all default settings, whereas {@link #builder()} copies
233    * the settings of the object called on.
234    *
235    * @return A new {@link JsonParserBuilder} object.
236    */
237   public static JsonParserBuilder create() {
238      return new JsonParserBuilder();
239   }
240
241   @Override /* Parser */
242   public JsonParserSession createSession() {
243      return createSession(createDefaultSessionArgs());
244   }
245
246   @Override /* Parser */
247   public JsonParserSession createSession(ParserSessionArgs args) {
248      return new JsonParserSession(this, args);
249   }
250
251   //-----------------------------------------------------------------------------------------------------------------
252   // Properties
253   //-----------------------------------------------------------------------------------------------------------------
254
255   /**
256    * Configuration property:  Validate end.
257    *
258    * @see #JSON_validateEnd
259    * @return
260    *    <jk>true</jk> if after parsing a POJO from the input, verifies that the remaining input in
261    *    the stream consists of only comments or whitespace.
262    */
263   protected final boolean isValidateEnd() {
264      return validateEnd;
265   }
266
267   //-----------------------------------------------------------------------------------------------------------------
268   // Other methods
269   //-----------------------------------------------------------------------------------------------------------------
270
271   @Override /* Context */
272   public ObjectMap toMap() {
273      return super.toMap()
274         .append("JsonParser", new DefaultFilteringObjectMap());
275   }
276}