Source code

001/*******************************************************************************
002 * Copyright (c) 2013, 2015 EclipseSource.
003 *
004 * Permission is hereby granted, free of charge, to any person obtaining a copy
005 * of this software and associated documentation files (the "Software"), to deal
006 * in the Software without restriction, including without limitation the rights
007 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
008 * copies of the Software, and to permit persons to whom the Software is
009 * furnished to do so, subject to the following conditions:
010 *
011 * The above copyright notice and this permission notice shall be included in all
012 * copies or substantial portions of the Software.
013 *
014 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
015 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
016 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
017 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
018 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
019 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
020 * SOFTWARE.
021 ******************************************************************************/
022package com.restfb.json;
023
024import java.io.IOException;
025import java.io.ObjectInputStream;
026import java.util.*;
027
028import com.restfb.json.JsonObject.Member;
029
030/**
031 * Represents a JSON object, a set of name/value pairs, where the names are strings and the values are JSON values.
032 * <p>
033 * Members can be added using the <code>add(String, ...)</code> methods which accept instances of {@link JsonValue},
034 * strings, primitive numbers, and boolean values. To modify certain values of an object, use the
035 * <code>set(String, ...)</code> methods. Please note that the <code>add</code> methods are faster than <code>set</code>
036 * as they do not search for existing members. On the other hand, the <code>add</code> methods do not prevent adding
037 * multiple members with the same name. Duplicate names are discouraged but not prohibited by JSON.
038 * </p>
039 * <p>
040 * Members can be accessed by their name using {@link #get(String)}. A list of all names can be obtained from the method
041 * {@link #names()}. This class also supports iterating over the members in document order using an {@link #iterator()}
042 * or an enhanced for loop:
043 * </p>
044 * 
045 * <pre>
046 * for (Member member : jsonObject) {
047 *   String name = member.getName();
048 *   JsonValue value = member.getValue();
049 *   ...
050 * }
051 * </pre>
052 * <p>
053 * Even though JSON objects are unordered by definition, instances of this class preserve the order of members to allow
054 * processing in document order and to guarantee a predictable output.
055 * </p>
056 * <p>
057 * Note that this class is <strong>not thread-safe</strong>. If multiple threads access a <code>JsonObject</code>
058 * instance concurrently, while at least one of these threads modifies the contents of this object, access to the
059 * instance must be synchronized externally. Failure to do so may lead to an inconsistent state.
060 * </p>
061 * <p>
062 * This class is <strong>not supposed to be extended</strong> by clients.
063 * </p>
064 */
065@SuppressWarnings("serial") // use default serial UID
066public class JsonObject extends JsonValue implements Iterable<Member> {
067
068  private final List<String> names;
069  private final List<JsonValue> values;
070  private transient HashIndexTable table;
071
072  /**
073   * Creates a new empty JsonObject.
074   */
075  public JsonObject() {
076    names = new ArrayList<>();
077    values = new ArrayList<>();
078    table = new HashIndexTable();
079  }
080
081  /**
082   * Creates a new JsonObject, initialized with the contents of the specified JSON object.
083   *
084   * @param object
085   *          the JSON object to get the initial contents from, must not be <code>null</code>
086   */
087  public JsonObject(JsonObject object) {
088    this(object, false);
089  }
090
091  private JsonObject(JsonObject object, boolean unmodifiable) {
092    Objects.requireNonNull(object, OBJECT_IS_NULL);
093    if (unmodifiable) {
094      names = Collections.unmodifiableList(object.names);
095      values = Collections.unmodifiableList(object.values);
096    } else {
097      names = new ArrayList<>(object.names);
098      values = new ArrayList<>(object.values);
099    }
100    table = new HashIndexTable();
101    updateHashIndex();
102  }
103
104  /**
105   * Returns an unmodifiable JsonObject for the specified one. This method allows to provide read-only access to a
106   * JsonObject.
107   * <p>
108   * The returned JsonObject is backed by the given object and reflect changes that happen to it. Attempts to modify the
109   * returned JsonObject result in an <code>UnsupportedOperationException</code>.
110   * </p>
111   *
112   * @param object
113   *          the JsonObject for which an unmodifiable JsonObject is to be returned
114   * @return an unmodifiable view of the specified JsonObject
115   */
116  public static JsonObject unmodifiableObject(JsonObject object) {
117    return new JsonObject(object, true);
118  }
119
120  /**
121   * Appends a new member to the end of this object, with the specified name and the JSON representation of the
122   * specified <code>int</code> value.
123   * <p>
124   * This method <strong>does not prevent duplicate names</strong>. Calling this method with a name that already exists
125   * in the object will append another member with the same name. In order to replace existing members, use the method
126   * <code>set(name, value)</code> instead. However, <strong> <em>add</em> is much faster than <em>set</em></strong>
127   * (because it does not need to search for existing members). Therefore <em>add</em> should be preferred when
128   * constructing new objects.
129   * </p>
130   *
131   * @param name
132   *          the name of the member to add
133   * @param value
134   *          the value of the member to add
135   * @return the object itself, to enable method chaining
136   */
137  public JsonObject add(String name, int value) {
138    add(name, Json.value(value));
139    return this;
140  }
141
142  /**
143   * Appends a new member to the end of this object, with the specified name and the JSON representation of the
144   * specified <code>long</code> value.
145   * <p>
146   * This method <strong>does not prevent duplicate names</strong>. Calling this method with a name that already exists
147   * in the object will append another member with the same name. In order to replace existing members, use the method
148   * <code>set(name, value)</code> instead. However, <strong> <em>add</em> is much faster than <em>set</em></strong>
149   * (because it does not need to search for existing members). Therefore <em>add</em> should be preferred when
150   * constructing new objects.
151   * </p>
152   *
153   * @param name
154   *          the name of the member to add
155   * @param value
156   *          the value of the member to add
157   * @return the object itself, to enable method chaining
158   */
159  public JsonObject add(String name, long value) {
160    add(name, Json.value(value));
161    return this;
162  }
163
164  /**
165   * Appends a new member to the end of this object, with the specified name and the JSON representation of the
166   * specified <code>float</code> value.
167   * <p>
168   * This method <strong>does not prevent duplicate names</strong>. Calling this method with a name that already exists
169   * in the object will append another member with the same name. In order to replace existing members, use the method
170   * <code>set(name, value)</code> instead. However, <strong> <em>add</em> is much faster than <em>set</em></strong>
171   * (because it does not need to search for existing members). Therefore <em>add</em> should be preferred when
172   * constructing new objects.
173   * </p>
174   *
175   * @param name
176   *          the name of the member to add
177   * @param value
178   *          the value of the member to add
179   * @return the object itself, to enable method chaining
180   */
181  public JsonObject add(String name, float value) {
182    add(name, Json.value(value));
183    return this;
184  }
185
186  /**
187   * Appends a new member to the end of this object, with the specified name and the JSON representation of the
188   * specified <code>double</code> value.
189   * <p>
190   * This method <strong>does not prevent duplicate names</strong>. Calling this method with a name that already exists
191   * in the object will append another member with the same name. In order to replace existing members, use the method
192   * <code>set(name, value)</code> instead. However, <strong> <em>add</em> is much faster than <em>set</em></strong>
193   * (because it does not need to search for existing members). Therefore <em>add</em> should be preferred when
194   * constructing new objects.
195   * </p>
196   *
197   * @param name
198   *          the name of the member to add
199   * @param value
200   *          the value of the member to add
201   * @return the object itself, to enable method chaining
202   */
203  public JsonObject add(String name, double value) {
204    add(name, Json.value(value));
205    return this;
206  }
207
208  /**
209   * Appends a new member to the end of this object, with the specified name and the JSON representation of the
210   * specified <code>boolean</code> value.
211   * <p>
212   * This method <strong>does not prevent duplicate names</strong>. Calling this method with a name that already exists
213   * in the object will append another member with the same name. In order to replace existing members, use the method
214   * <code>set(name, value)</code> instead. However, <strong> <em>add</em> is much faster than <em>set</em></strong>
215   * (because it does not need to search for existing members). Therefore <em>add</em> should be preferred when
216   * constructing new objects.
217   * </p>
218   *
219   * @param name
220   *          the name of the member to add
221   * @param value
222   *          the value of the member to add
223   * @return the object itself, to enable method chaining
224   */
225  public JsonObject add(String name, boolean value) {
226    add(name, Json.value(value));
227    return this;
228  }
229
230  /**
231   * Appends a new member to the end of this object, with the specified name and the JSON representation of the
232   * specified string.
233   * <p>
234   * This method <strong>does not prevent duplicate names</strong>. Calling this method with a name that already exists
235   * in the object will append another member with the same name. In order to replace existing members, use the method
236   * <code>set(name, value)</code> instead. However, <strong> <em>add</em> is much faster than <em>set</em></strong>
237   * (because it does not need to search for existing members). Therefore <em>add</em> should be preferred when
238   * constructing new objects.
239   * </p>
240   *
241   * @param name
242   *          the name of the member to add
243   * @param value
244   *          the value of the member to add
245   * @return the object itself, to enable method chaining
246   */
247  public JsonObject add(String name, String value) {
248    add(name, Json.value(value));
249    return this;
250  }
251
252  /**
253   * Appends a new member to the end of this object, with the specified name and the specified JSON value.
254   * <p>
255   * This method <strong>does not prevent duplicate names</strong>. Calling this method with a name that already exists
256   * in the object will append another member with the same name. In order to replace existing members, use the method
257   * <code>set(name, value)</code> instead. However, <strong> <em>add</em> is much faster than <em>set</em></strong>
258   * (because it does not need to search for existing members). Therefore <em>add</em> should be preferred when
259   * constructing new objects.
260   * </p>
261   *
262   * @param name
263   *          the name of the member to add
264   * @param value
265   *          the value of the member to add, must not be <code>null</code>
266   * @return the object itself, to enable method chaining
267   */
268  public JsonObject add(String name, JsonValue value) {
269    Objects.requireNonNull(name, NAME_IS_NULL);
270    Objects.requireNonNull(value, VALUE_IS_NULL);
271    table.add(name, names.size());
272    names.add(name);
273    values.add(value);
274    return this;
275  }
276
277  /**
278   * Sets the value of the member with the specified name to the JSON representation of the specified <code>int</code>
279   * value. If this object does not contain a member with this name, a new member is added at the end of the object. If
280   * this object contains multiple members with this name, only the last one is changed.
281   * <p>
282   * This method should <strong>only be used to modify existing objects</strong>. To fill a new object with members, the
283   * method <code>add(name, value)</code> should be preferred which is much faster (as it does not need to search for
284   * existing members).
285   * </p>
286   *
287   * @param name
288   *          the name of the member to replace
289   * @param value
290   *          the value to set to the member
291   * @return the object itself, to enable method chaining
292   */
293  public JsonObject set(String name, int value) {
294    set(name, Json.value(value));
295    return this;
296  }
297
298  /**
299   * Sets the value of the member with the specified name to the JSON representation of the specified <code>long</code>
300   * value. If this object does not contain a member with this name, a new member is added at the end of the object. If
301   * this object contains multiple members with this name, only the last one is changed.
302   * <p>
303   * This method should <strong>only be used to modify existing objects</strong>. To fill a new object with members, the
304   * method <code>add(name, value)</code> should be preferred which is much faster (as it does not need to search for
305   * existing members).
306   * </p>
307   *
308   * @param name
309   *          the name of the member to replace
310   * @param value
311   *          the value to set to the member
312   * @return the object itself, to enable method chaining
313   */
314  public JsonObject set(String name, long value) {
315    set(name, Json.value(value));
316    return this;
317  }
318
319  /**
320   * Sets the value of the member with the specified name to the JSON representation of the specified <code>float</code>
321   * value. If this object does not contain a member with this name, a new member is added at the end of the object. If
322   * this object contains multiple members with this name, only the last one is changed.
323   * <p>
324   * This method should <strong>only be used to modify existing objects</strong>. To fill a new object with members, the
325   * method <code>add(name, value)</code> should be preferred which is much faster (as it does not need to search for
326   * existing members).
327   * </p>
328   *
329   * @param name
330   *          the name of the member to add
331   * @param value
332   *          the value of the member to add
333   * @return the object itself, to enable method chaining
334   */
335  public JsonObject set(String name, float value) {
336    set(name, Json.value(value));
337    return this;
338  }
339
340  /**
341   * Sets the value of the member with the specified name to the JSON representation of the specified
342   * <code>double</code> value. If this object does not contain a member with this name, a new member is added at the
343   * end of the object. If this object contains multiple members with this name, only the last one is changed.
344   * <p>
345   * This method should <strong>only be used to modify existing objects</strong>. To fill a new object with members, the
346   * method <code>add(name, value)</code> should be preferred which is much faster (as it does not need to search for
347   * existing members).
348   * </p>
349   *
350   * @param name
351   *          the name of the member to add
352   * @param value
353   *          the value of the member to add
354   * @return the object itself, to enable method chaining
355   */
356  public JsonObject set(String name, double value) {
357    set(name, Json.value(value));
358    return this;
359  }
360
361  /**
362   * Sets the value of the member with the specified name to the JSON representation of the specified
363   * <code>boolean</code> value. If this object does not contain a member with this name, a new member is added at the
364   * end of the object. If this object contains multiple members with this name, only the last one is changed.
365   * <p>
366   * This method should <strong>only be used to modify existing objects</strong>. To fill a new object with members, the
367   * method <code>add(name, value)</code> should be preferred which is much faster (as it does not need to search for
368   * existing members).
369   * </p>
370   *
371   * @param name
372   *          the name of the member to add
373   * @param value
374   *          the value of the member to add
375   * @return the object itself, to enable method chaining
376   */
377  public JsonObject set(String name, boolean value) {
378    set(name, Json.value(value));
379    return this;
380  }
381
382  /**
383   * Sets the value of the member with the specified name to the JSON representation of the specified string. If this
384   * object does not contain a member with this name, a new member is added at the end of the object. If this object
385   * contains multiple members with this name, only the last one is changed.
386   * <p>
387   * This method should <strong>only be used to modify existing objects</strong>. To fill a new object with members, the
388   * method <code>add(name, value)</code> should be preferred which is much faster (as it does not need to search for
389   * existing members).
390   * </p>
391   *
392   * @param name
393   *          the name of the member to add
394   * @param value
395   *          the value of the member to add
396   * @return the object itself, to enable method chaining
397   */
398  public JsonObject set(String name, String value) {
399    set(name, Json.value(value));
400    return this;
401  }
402
403  /**
404   * Sets the value of the member with the specified name to the specified JSON value. If this object does not contain a
405   * member with this name, a new member is added at the end of the object. If this object contains multiple members
406   * with this name, only the last one is changed.
407   * <p>
408   * This method should <strong>only be used to modify existing objects</strong>. To fill a new object with members, the
409   * method <code>add(name, value)</code> should be preferred which is much faster (as it does not need to search for
410   * existing members).
411   * </p>
412   *
413   * @param name
414   *          the name of the member to add
415   * @param value
416   *          the value of the member to add, must not be <code>null</code>
417   * @return the object itself, to enable method chaining
418   */
419  public JsonObject set(String name, JsonValue value) {
420    Objects.requireNonNull(name, NAME_IS_NULL);
421    Objects.requireNonNull(value, VALUE_IS_NULL);
422    int index = indexOf(name);
423    if (index != -1) {
424      values.set(index, value);
425    } else {
426      table.add(name, names.size());
427      names.add(name);
428      values.add(value);
429    }
430    return this;
431  }
432
433  /**
434   * Removes a member with the specified name from this object. If this object contains multiple members with the given
435   * name, only the last one is removed. If this object does not contain a member with the specified name, the object is
436   * not modified.
437   *
438   * @param name
439   *          the name of the member to remove
440   * @return the object itself, to enable method chaining
441   */
442  public JsonObject remove(String name) {
443    Objects.requireNonNull(name, NAME_IS_NULL);
444    int index = indexOf(name);
445    if (index != -1) {
446      table.remove(index);
447      names.remove(index);
448      values.remove(index);
449    }
450    return this;
451  }
452
453  /**
454   * Checks if a specified member is present as a child of this object. This will not test if
455   * this object contains the literal <code>null</code>, {@link JsonValue#isNull()} should be used
456   * for this purpose.
457   *
458   * @param name
459   *          the name of the member to check for
460   * @return whether or not the member is present
461   */
462  public boolean contains(String name) {
463    return names.contains(name);
464  }
465
466  /**
467   * Copies all members of the specified object into this object. When the specified object contains
468   * members with names that also exist in this object, the existing values in this object will be
469   * replaced by the corresponding values in the specified object.
470   *
471   * @param object
472   *          the object to merge
473   * @return the object itself, to enable method chaining
474   */
475  public JsonObject merge(JsonObject object) {
476    Objects.requireNonNull(object, OBJECT_IS_NULL);
477    for (Member member : object) {
478      this.set(member.name, member.value);
479    }
480    return this;
481  }
482
483  /**
484   * Returns the value of the member with the specified name in this object. If this object contains multiple members
485   * with the given name, this method will return the last one.
486   *
487   * @param name
488   *          the name of the member whose value is to be returned
489   * @return the value of the last member with the specified name, or <code>null</code> if this object does not contain
490   *         a member with that name
491   */
492  public JsonValue get(String name) {
493    Objects.requireNonNull(name, NAME_IS_NULL);
494    int index = indexOf(name);
495    return index != -1 ? values.get(index) : null;
496  }
497
498  /**
499   * Returns the <code>int</code> value of the member with the specified name in this object. If this object does not
500   * contain a member with this name, the given default value is returned. If this object contains multiple members with
501   * the given name, the last one will be picked. If this member's value does not represent a JSON number or if it
502   * cannot be interpreted as Java <code>int</code>, an exception is thrown.
503   *
504   * @param name
505   *          the name of the member whose value is to be returned
506   * @param defaultValue
507   *          the value to be returned if the requested member is missing
508   * @return the value of the last member with the specified name, or the given default value if this object does not
509   *         contain a member with that name
510   */
511  public int getInt(String name, int defaultValue) {
512    JsonValue value = get(name);
513    return value != null ? value.asInt() : defaultValue;
514  }
515
516  /**
517   * Returns the <code>long</code> value of the member with the specified name in this object. If this object does not
518   * contain a member with this name, the given default value is returned. If this object contains multiple members with
519   * the given name, the last one will be picked. If this member's value does not represent a JSON number or if it
520   * cannot be interpreted as Java <code>long</code>, an exception is thrown.
521   *
522   * @param name
523   *          the name of the member whose value is to be returned
524   * @param defaultValue
525   *          the value to be returned if the requested member is missing
526   * @return the value of the last member with the specified name, or the given default value if this object does not
527   *         contain a member with that name
528   */
529  public long getLong(String name, long defaultValue) {
530    JsonValue value = get(name);
531    return value != null ? value.asLong() : defaultValue;
532  }
533
534  /**
535   * Returns the <code>float</code> value of the member with the specified name in this object. If this object does not
536   * contain a member with this name, the given default value is returned. If this object contains multiple members with
537   * the given name, the last one will be picked. If this member's value does not represent a JSON number or if it
538   * cannot be interpreted as Java <code>float</code>, an exception is thrown.
539   *
540   * @param name
541   *          the name of the member whose value is to be returned
542   * @param defaultValue
543   *          the value to be returned if the requested member is missing
544   * @return the value of the last member with the specified name, or the given default value if this object does not
545   *         contain a member with that name
546   */
547  public float getFloat(String name, float defaultValue) {
548    JsonValue value = get(name);
549    return value != null ? value.asFloat() : defaultValue;
550  }
551
552  /**
553   * Returns the <code>double</code> value of the member with the specified name in this object. If this object does not
554   * contain a member with this name, the given default value is returned. If this object contains multiple members with
555   * the given name, the last one will be picked. If this member's value does not represent a JSON number or if it
556   * cannot be interpreted as Java <code>double</code>, an exception is thrown.
557   *
558   * @param name
559   *          the name of the member whose value is to be returned
560   * @param defaultValue
561   *          the value to be returned if the requested member is missing
562   * @return the value of the last member with the specified name, or the given default value if this object does not
563   *         contain a member with that name
564   */
565  public double getDouble(String name, double defaultValue) {
566    JsonValue value = get(name);
567    return value != null ? value.asDouble() : defaultValue;
568  }
569
570  /**
571   * Returns the <code>boolean</code> value of the member with the specified name in this object. If this object does
572   * not contain a member with this name, the given default value is returned. If this object contains multiple members
573   * with the given name, the last one will be picked. If this member's value does not represent a JSON
574   * <code>true</code> or <code>false</code> value, an exception is thrown.
575   *
576   * @param name
577   *          the name of the member whose value is to be returned
578   * @param defaultValue
579   *          the value to be returned if the requested member is missing
580   * @return the value of the last member with the specified name, or the given default value if this object does not
581   *         contain a member with that name
582   */
583  public boolean getBoolean(String name, boolean defaultValue) {
584    JsonValue value = get(name);
585    return value != null ? value.asBoolean() : defaultValue;
586  }
587
588  /**
589   * Returns the <code>String</code> value of the member with the specified name in this object. If this object does not
590   * contain a member with this name, the given default value is returned. If this object contains multiple members with
591   * the given name, the last one is picked. If this member's value does not represent a JSON string, an exception is
592   * thrown.
593   *
594   * @param name
595   *          the name of the member whose value is to be returned
596   * @param defaultValue
597   *          the value to be returned if the requested member is missing
598   * @return the value of the last member with the specified name, or the given default value if this object does not
599   *         contain a member with that name
600   */
601  public String getString(String name, String defaultValue) {
602    JsonValue value = get(name);
603    return value != null ? value.asString() : defaultValue;
604  }
605
606  /**
607   * Returns the number of members (name/value pairs) in this object.
608   *
609   * @return the number of members in this object
610   */
611  public int size() {
612    return names.size();
613  }
614
615  /**
616   * Returns <code>true</code> if this object contains no members.
617   *
618   * @return <code>true</code> if this object contains no members
619   */
620  public boolean isEmpty() {
621    return names.isEmpty();
622  }
623
624  /**
625   * Returns a list of the names in this object in document order. The returned list is backed by this object and will
626   * reflect subsequent changes. It cannot be used to modify this object. Attempts to modify the returned list will
627   * result in an exception.
628   *
629   * @return a list of the names in this object
630   */
631  public List<String> names() {
632    return Collections.unmodifiableList(names);
633  }
634
635  /**
636   * Returns an iterator over the members of this object in document order. The returned iterator cannot be used to
637   * modify this object.
638   *
639   * @return an iterator over the members of this object
640   */
641  public Iterator<Member> iterator() {
642    final Iterator<String> namesIterator = names.iterator();
643    final Iterator<JsonValue> valuesIterator = values.iterator();
644    return new Iterator<JsonObject.Member>() {
645
646      @Override
647      public boolean hasNext() {
648        return namesIterator.hasNext();
649      }
650
651      @Override
652      public Member next() {
653        String name = namesIterator.next();
654        JsonValue value = valuesIterator.next();
655        return new Member(name, value);
656      }
657
658      @Override
659      public void remove() {
660        throw new UnsupportedOperationException();
661      }
662
663    };
664  }
665
666  @Override
667  void write(JsonWriter writer) throws IOException {
668    writer.writeObjectOpen();
669    Iterator<String> namesIterator = names.iterator();
670    Iterator<JsonValue> valuesIterator = values.iterator();
671    if (namesIterator.hasNext()) {
672      writer.writeMemberName(namesIterator.next());
673      writer.writeMemberSeparator();
674      valuesIterator.next().write(writer);
675      while (namesIterator.hasNext()) {
676        writer.writeObjectSeparator();
677        writer.writeMemberName(namesIterator.next());
678        writer.writeMemberSeparator();
679        valuesIterator.next().write(writer);
680      }
681    }
682    writer.writeObjectClose();
683  }
684
685  @Override
686  public boolean isObject() {
687    return true;
688  }
689
690  @Override
691  public JsonObject asObject() {
692    return this;
693  }
694
695  @Override
696  public int hashCode() {
697    int result = 1;
698    result = 31 * result + names.hashCode();
699    result = 31 * result + values.hashCode();
700    return result;
701  }
702
703  @Override
704  public boolean equals(Object obj) {
705    if (this == obj) {
706      return true;
707    }
708    if (obj == null) {
709      return false;
710    }
711    if (getClass() != obj.getClass()) {
712      return false;
713    }
714    JsonObject other = (JsonObject) obj;
715    return names.equals(other.names) && values.equals(other.values);
716  }
717
718  int indexOf(String name) {
719    int index = table.get(name);
720    if (index != -1 && name.equals(names.get(index))) {
721      return index;
722    }
723    return names.lastIndexOf(name);
724  }
725
726  private synchronized void readObject(ObjectInputStream inputStream) throws IOException, ClassNotFoundException {
727    inputStream.defaultReadObject();
728    table = new HashIndexTable();
729    updateHashIndex();
730  }
731
732  private void updateHashIndex() {
733    int size = names.size();
734    for (int i = 0; i < size; i++) {
735      table.add(names.get(i), i);
736    }
737  }
738
739  /**
740   * Represents a member of a JSON object, a pair of a name and a value.
741   */
742  public static class Member {
743
744    private final String name;
745    private final JsonValue value;
746
747    Member(String name, JsonValue value) {
748      this.name = name;
749      this.value = value;
750    }
751
752    /**
753     * Returns the name of this member.
754     *
755     * @return the name of this member, never <code>null</code>
756     */
757    public String getName() {
758      return name;
759    }
760
761    /**
762     * Returns the value of this member.
763     *
764     * @return the value of this member, never <code>null</code>
765     */
766    public JsonValue getValue() {
767      return value;
768    }
769
770    @Override
771    public int hashCode() {
772      int result = 1;
773      result = 31 * result + name.hashCode();
774      result = 31 * result + value.hashCode();
775      return result;
776    }
777
778    /**
779     * Indicates whether a given object is "equal to" this JsonObject. An object is considered equal
780     * if it is also a <code>JsonObject</code> and both objects contain the same members <em>in
781     * the same order</em>.
782     * <p>
783     * If two JsonObjects are equal, they will also produce the same JSON output.
784     * </p>
785     *
786     * @param object
787     *          the object to be compared with this JsonObject
788     * @return <tt>true</tt> if the specified object is equal to this JsonObject, <code>false</code>
789     *         otherwise
790     */
791    @Override
792    public boolean equals(Object object) {
793      if (this == object) {
794        return true;
795      }
796      if (object == null) {
797        return false;
798      }
799      if (getClass() != object.getClass()) {
800        return false;
801      }
802      Member other = (Member)object;
803      return name.equals(other.name) && value.equals(other.value);
804    }
805
806  }
807
808  static class HashIndexTable {
809
810    private final byte[] hashTable = new byte[32]; // must be a power of two
811
812    public HashIndexTable() {
813        // nothing to do here
814    }
815
816    public HashIndexTable(HashIndexTable original) {
817      System.arraycopy(original.hashTable, 0, hashTable, 0, hashTable.length);
818    }
819
820    void add(String name, int index) {
821      int slot = hashSlotFor(name);
822      if (index < 0xff) {
823        // increment by 1, 0 stands for empty
824        hashTable[slot] = (byte) (index + 1);
825      } else {
826        hashTable[slot] = 0;
827      }
828    }
829
830    void remove(int index) {
831      for (int i = 0; i < hashTable.length; i++) {
832        if (hashTable[i] == index + 1) {
833          hashTable[i] = 0;
834        } else if (hashTable[i] > index + 1) {
835          hashTable[i]--;
836        }
837      }
838    }
839
840    int get(Object name) {
841      int slot = hashSlotFor(name);
842      // subtract 1, 0 stands for empty
843      return (hashTable[slot] & 0xff) - 1;
844    }
845
846    private int hashSlotFor(Object element) {
847      return element.hashCode() & hashTable.length - 1;
848    }
849
850  }
851
852}