001    /*
002     * Copyright 2015-2016 UnboundID Corp.
003     * All Rights Reserved.
004     */
005    /*
006     * Copyright (C) 2015-2016 UnboundID Corp.
007     *
008     * This program is free software; you can redistribute it and/or modify
009     * it under the terms of the GNU General Public License (GPLv2 only)
010     * or the terms of the GNU Lesser General Public License (LGPLv2.1 only)
011     * as published by the Free Software Foundation.
012     *
013     * This program is distributed in the hope that it will be useful,
014     * but WITHOUT ANY WARRANTY; without even the implied warranty of
015     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
016     * GNU General Public License for more details.
017     *
018     * You should have received a copy of the GNU General Public License
019     * along with this program; if not, see <http://www.gnu.org/licenses>.
020     */
021    package com.unboundid.util.json;
022    
023    
024    
025    import com.unboundid.util.NotMutable;
026    import com.unboundid.util.ThreadSafety;
027    import com.unboundid.util.ThreadSafetyLevel;
028    
029    
030    
031    /**
032     * This class provides an implementation of a JSON value that represents a null
033     * value.  The string representation of the null value is {@code null} in all
034     * lowercase and without any quotation marks.
035     */
036    @NotMutable()
037    @ThreadSafety(level=ThreadSafetyLevel.COMPLETELY_THREADSAFE)
038    public final class JSONNull
039           extends JSONValue
040    {
041      /**
042       * A pre-allocated JSON null value object.
043       */
044      public static final JSONNull NULL = new JSONNull();
045    
046    
047    
048      /**
049       * The serial version UID for this serializable class.
050       */
051      private static final long serialVersionUID = -8359265286375144526L;
052    
053    
054    
055      /**
056       * Creates a new JSON value capable of representing a {@code null} value.
057       */
058      public JSONNull()
059      {
060      }
061    
062    
063    
064      /**
065       * {@inheritDoc}
066       */
067      @Override()
068      public int hashCode()
069      {
070        return 1;
071      }
072    
073    
074    
075      /**
076       * {@inheritDoc}
077       */
078      @Override()
079      public boolean equals(final Object o)
080      {
081        return ((o == this) || (o instanceof JSONNull));
082      }
083    
084    
085    
086      /**
087       * {@inheritDoc}
088       */
089      @Override()
090      public boolean equals(final JSONValue v, final boolean ignoreFieldNameCase,
091                            final boolean ignoreValueCase,
092                            final boolean ignoreArrayOrder)
093      {
094        return (v instanceof JSONNull);
095      }
096    
097    
098    
099      /**
100       * {@inheritDoc}
101       */
102      @Override()
103      public String toString()
104      {
105        return "null";
106      }
107    
108    
109    
110      /**
111       * {@inheritDoc}
112       */
113      @Override()
114      public void toString(final StringBuilder buffer)
115      {
116        buffer.append("null");
117      }
118    
119    
120    
121      /**
122       * {@inheritDoc}
123       */
124      @Override()
125      public String toSingleLineString()
126      {
127        return "null";
128      }
129    
130    
131    
132      /**
133       * {@inheritDoc}
134       */
135      @Override()
136      public void toSingleLineString(final StringBuilder buffer)
137      {
138        buffer.append("null");
139      }
140    
141    
142    
143      /**
144       * {@inheritDoc}
145       */
146      @Override()
147      public String toNormalizedString()
148      {
149        return "null";
150      }
151    
152    
153    
154      /**
155       * {@inheritDoc}
156       */
157      @Override()
158      public void toNormalizedString(final StringBuilder buffer)
159      {
160        buffer.append("null");
161      }
162    
163    
164    
165      /**
166       * {@inheritDoc}
167       */
168      @Override()
169      public void appendToJSONBuffer(final JSONBuffer buffer)
170      {
171        buffer.appendNull();
172      }
173    
174    
175    
176      /**
177       * {@inheritDoc}
178       */
179      @Override()
180      public void appendToJSONBuffer(final String fieldName,
181                                     final JSONBuffer buffer)
182      {
183        buffer.appendNull(fieldName);
184      }
185    }