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   package org.richfaces.json;
   
   /*
    Copyright (c) 2002 JSON.org
   
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   copies of the Software, and to permit persons to whom the Software is
   furnished to do so, subject to the following conditions:
  
   The above copyright notice and this permission notice shall be included in all
   copies or substantial portions of the Software.
  
   The Software shall be used for Good, not Evil.
  
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   SOFTWARE.
   */
  
  import java.io.Writer;
  import java.util.HashMap;
  import java.util.Map;

A JSONObject is an unordered collection of name/value pairs. Its external form is a string wrapped in curly braces with colons between the names and values, and commas between the values and names. The internal form is an object having get and opt methods for accessing the values by name, and put methods for adding or replacing values by name. The values can be any of these types: Boolean, JSONArray, JSONObject, Number, String, or the JSONObject.NULL object. A JSONObject constructor can be used to convert an external form JSON text into an internal form whose values can be retrieved with the get and opt methods, or to convert values into a JSON text using the put and toString methods. A get method returns a value if one can be found, and throws an exception if one cannot be found. An opt method returns a default value instead of throwing an exception, and so is useful for obtaining optional values.

The generic get() and opt() methods return an object, which you can cast or query for type. There are also typed get and opt methods that do type checking and type coersion for you.

The put methods adds values to an object. For example,

 myString = new JSONObject().put("JSON", "Hello, World!").toString();
 
produces the string {"JSON": "Hello, World"}.

The texts produced by the toString methods strictly conform to the JSON sysntax rules. The constructors are more forgiving in the texts they will accept:

  • An extra , (comma) may appear just before the closing brace.
  • Strings may be quoted with ' (single quote).
  • Strings do not need to be quoted at all if they do not begin with a quote or single quote, and if they do not contain leading or trailing spaces, and if they do not contain any of these characters: { } [ ] / \ : , = ; # and if they do not look like numbers and if they are not the reserved words true, false, or null.
  • Keys can be followed by = or => as well as by :.
  • Values can be followed by ; (semicolon) as well as by , (comma).
  • Numbers may have the 0- (octal) or 0x- (hex) prefix.
  • Comments written in the slashshlash, slashstar, and hash conventions will be ignored.

Author(s):
JSON.org
Version:
2
  
  public class JSONObject implements Serializable {
    
It is sometimes more convenient and less ambiguous to have a NULL object than to use Java's null value. JSONObject.NULL.equals(null) returns true. JSONObject.NULL.toString() returns "null".
  
      public static final Object NULL = new Null();
    
  
      private static final long serialVersionUID = -3779657348977645510L;
    
The hash map where the JSONObject's properties are kept.
  
      private Map myHashMap;

    
Construct an empty JSONObject.
  
      public JSONObject() {
          this. = new HashMap();
      }

    
Construct a JSONObject from a JSONTokener.

Parameters:
x A JSONTokener object containing the source string.
Throws:
JSONException If there is a syntax error in the source string.
 
     public JSONObject(JSONTokener xthrows JSONException {
         this();
 
         char c;
         String key;
 
         if (x.nextClean() != '{') {
             throw x.syntaxError("A JSONObject text must begin with '{'");
         }
 
         for (;;) {
             c = x.nextClean();
 
             switch (c) {
                 case 0:
                     throw x.syntaxError("A JSONObject text must end with '}'");
 
                 case '}':
                     return;
 
                 default:
                     x.back();
                     key = x.nextValue().toString();
             }
 
             /*
              * The key is followed by ':'. We will also tolerate '=' or '=>'.
              */
             c = x.nextClean();
 
             if (c == '=') {
                 if (x.next() != '>') {
                     x.back();
                 }
             } else if (c != ':') {
                 throw x.syntaxError("Expected a ':' after a key");
             }
 
             put(keyx.nextValue());
 
             /*
              * Pairs are separated by ','. We will also tolerate ';'.
              */
             switch (x.nextClean()) {
                 case ';':
                 case ',':
                     if (x.nextClean() == '}') {
                         return;
                     }
 
                     x.back();
 
                     break;
 
                 case '}':
                     return;
 
                 default:
                     throw x.syntaxError("Expected a ',' or '}'");
             }
         }
     }

    
Construct a JSONObject from a Map.

Parameters:
map A map object that can be used to initialize the contents of the JSONObject.
 
     public JSONObject(Map map) {
         this. = (map == null) ? new HashMap() : new HashMap(map);
     }

    
Construct a JSONObject from a string. This is the most commonly used JSONObject constructor.

Parameters:
string A string beginning with { (left brace) and ending with }  (right brace).
Throws:
JSONException If there is a syntax error in the source string.
 
     public JSONObject(String stringthrows JSONException {
         this(new JSONTokener(string));
     }

    
Construct a JSONObject from a subset of another JSONObject. An array of strings is used to identify the keys that should be copied. Missing keys are ignored.

Parameters:
jo A JSONObject.
sa An array of strings.
Throws:
JSONException If a value is a non-finite number.
 
     public JSONObject(JSONObject joString[] sathrows JSONException {
         this();
 
         for (int i = 0; i < sa.lengthi += 1) {
             putOpt(sa[i], jo.opt(sa[i]));
         }
     }

    
Construct a JSONObject from an Object, using reflection to find the public members. The resulting JSONObject's keys will be the strings from the names array, and the values will be the field values associated with those keys in the object. If a key is not found or not visible, then it will not be copied into the new JSONObject.

Parameters:
object An object that has fields that should be used to make a JSONObject.
names An array of strings, the names of the fields to be used from the object.
 
     public JSONObject(Object objectString[] names) {
         this();
 
         Class c = object.getClass();
 
         for (int i = 0; i < names.lengthi += 1) {
             try {
                 String name = names[i];
                 Field field = c.getField(name);
                 Object value = field.get(object);
 
                 this.put(namevalue);
             } catch (Exception e) {
 
                 /* forget about it */
             }
         }
     }

    
Accumulate values under a key. It is similar to the put method except that if there is already an object stored under the key then a JSONArray is stored under the key to hold all of the accumulated values. If there is already a JSONArray, then the new value is appended to it. In contrast, the put method replaces the previous value.

Parameters:
key A key string.
value An object to be accumulated under the key.
Returns:
this.
Throws:
JSONException If the value is an invalid number or if the key is null.
 
     public JSONObject accumulate(String keyObject valuethrows JSONException {
         testValidity(value);
 
         Object o = opt(key);
 
         if (o == null) {
             put(key, (value instanceof JSONArray) ? new JSONArray().put(value) : value);
         } else if (o instanceof JSONArray) {
             ((JSONArrayo).put(value);
         } else {
             put(keynew JSONArray().put(o).put(value));
         }
 
         return this;
     }

    
Append values to the array under a key. If the key does not exist in the JSONObject, then the key is put in the JSONObject with its value being a JSONArray containing the value parameter. If the key was already associated with a JSONArray, then the value parameter is appended to it.

Parameters:
key A key string.
value An object to be accumulated under the key.
Returns:
this.
Throws:
JSONException If the key is null or if the current value associated with the key is not a JSONArray.
 
     public JSONObject append(String keyObject valuethrows JSONException {
         testValidity(value);
 
         Object o = opt(key);
 
         if (o == null) {
             put(keynew JSONArray().put(value));
         } else if (o instanceof JSONArray) {
             put(key, ((JSONArrayo).put(value));
         } else {
             throw new JSONException("JSONObject[" + key + "] is not a JSONArray.");
         }
 
         return this;
     }

    
Produce a string from a double. The string "null" will be returned if the number is not finite.

Parameters:
d A double.
Returns:
A String.
 
     public static String doubleToString(double d) {
         if (Double.isInfinite(d) || Double.isNaN(d)) {
             return "null";
         }
 
         // Shave off trailing zeros and decimal point, if possible.
         String s = Double.toString(d);
 
         if ((s.indexOf('.') > 0) && (s.indexOf('e') < 0) && (s.indexOf('E') < 0)) {
             while (s.endsWith("0")) {
                 s = s.substring(0, s.length() - 1);
             }
 
             if (s.endsWith(".")) {
                 s = s.substring(0, s.length() - 1);
             }
         }
 
         return s;
     }

    
Get the value object associated with a key.

Parameters:
key A key string.
Returns:
The object associated with the key.
Throws:
JSONException if the key is not found.
 
     public Object get(String keythrows JSONException {
         Object o = opt(key);
 
         if (o == null) {
             throw new JSONException("JSONObject[" + quote(key) + "] not found.");
         }
 
         return o;
     }

    
Get the boolean value associated with a key.

Parameters:
key A key string.
Returns:
The truth.
Throws:
JSONException if the value is not a Boolean or the String "true" or "false".
 
     public boolean getBoolean(String keythrows JSONException {
         Object o = get(key);
 
         if (o.equals(.) || ((o instanceof String) && ((Stringo).equalsIgnoreCase("false"))) {
             return false;
         } else if (o.equals(.) || ((o instanceof String) && ((Stringo).equalsIgnoreCase("true"))) {
             return true;
         }
 
         throw new JSONException("JSONObject[" + quote(key) + "] is not a Boolean.");
     }

    
Get the double value associated with a key.

Parameters:
key A key string.
Returns:
The numeric value.
Throws:
JSONException if the key is not found or if the value is not a Number object and cannot be converted to a number.
 
     public double getDouble(String keythrows JSONException {
         Object o = get(key);
 
         try {
             return (o instanceof Number) ? ((Numbero).doubleValue() : Double.valueOf((Stringo).doubleValue();
         } catch (Exception e) {
             throw new JSONException("JSONObject[" + quote(key) + "] is not a number.");
         }
     }

    
Get the int value associated with a key. If the number value is too large for an int, it will be clipped.

Parameters:
key A key string.
Returns:
The integer value.
Throws:
JSONException if the key is not found or if the value cannot be converted to an integer.
 
     public int getInt(String keythrows JSONException {
         Object o = get(key);
 
         return (o instanceof Number) ? ((Numbero).intValue() : (intgetDouble(key);
     }

    
Get the JSONArray value associated with a key.

Parameters:
key A key string.
Returns:
A JSONArray which is the value.
Throws:
JSONException if the key is not found or if the value is not a JSONArray.
 
     public JSONArray getJSONArray(String keythrows JSONException {
         Object o = get(key);
 
         if (o instanceof JSONArray) {
             return (JSONArrayo;
         }
 
         throw new JSONException("JSONObject[" + quote(key) + "] is not a JSONArray.");
     }

    
Get the JSONObject value associated with a key.

Parameters:
key A key string.
Returns:
A JSONObject which is the value.
Throws:
JSONException if the key is not found or if the value is not a JSONObject.
 
     public JSONObject getJSONObject(String keythrows JSONException {
         Object o = get(key);
 
         if (o instanceof JSONObject) {
             return (JSONObjecto;
         }
 
         throw new JSONException("JSONObject[" + quote(key) + "] is not a JSONObject.");
     }

    
Get the long value associated with a key. If the number value is too long for a long, it will be clipped.

Parameters:
key A key string.
Returns:
The long value.
Throws:
JSONException if the key is not found or if the value cannot be converted to a long.
 
     public long getLong(String keythrows JSONException {
         Object o = get(key);
 
         return (o instanceof Number) ? ((Numbero).longValue() : (longgetDouble(key);
     }

    
Get the string associated with a key.

Parameters:
key A key string.
Returns:
A string which is the value.
Throws:
JSONException if the key is not found.
 
     public String getString(String keythrows JSONException {
         return get(key).toString();
     }

    
Determine if the JSONObject contains a specific key.

Parameters:
key A key string.
Returns:
true if the key exists in the JSONObject.
 
     public boolean has(String key) {
         return this..containsKey(key);
     }

    
Determine if the value associated with the key is null or if there is no value.

Parameters:
key A key string.
Returns:
true if there is no value associated with the key or if the value is the JSONObject.NULL object.
 
     public boolean isNull(String key) {
         return ..equals(opt(key));
     }

    
Get an enumeration of the keys of the JSONObject.

Returns:
An iterator of the keys.
 
     public Iterator keys() {
         return this..keySet().iterator();
     }

    
Get the number of keys stored in the JSONObject.

Returns:
The number of keys in the JSONObject.
 
     public int length() {
         return this..size();
     }

    
Produce a JSONArray containing the names of the elements of this JSONObject.

Returns:
A JSONArray containing the key strings, or null if the JSONObject is empty.
 
     public JSONArray names() {
         JSONArray ja = new JSONArray();
         Iterator keys = keys();
 
         while (keys.hasNext()) {
             ja.put(keys.next());
         }
 
         return (ja.length() == 0) ? null : ja;
     }

    
Produce a string from a Number.

Parameters:
n A Number
Returns:
A String.
Throws:
JSONException If n is a non-finite number.
 
     public static String numberToString(Number nthrows JSONException {
         if (n == null) {
             throw new JSONException("Null pointer");
         }
 
         testValidity(n);
 
         // Shave off trailing zeros and decimal point, if possible.
         String s = n.toString();
 
         if ((s.indexOf('.') > 0) && (s.indexOf('e') < 0) && (s.indexOf('E') < 0)) {
             while (s.endsWith("0")) {
                 s = s.substring(0, s.length() - 1);
             }
 
             if (s.endsWith(".")) {
                 s = s.substring(0, s.length() - 1);
             }
         }
 
         return s;
     }

    
Get an optional value associated with a key.

Parameters:
key A key string.
Returns:
An object which is the value, or null if there is no value.
 
     public Object opt(String key) {
         return (key == null) ? null : this..get(key);
     }

    
Get an optional boolean associated with a key. It returns false if there is no such key, or if the value is not Boolean.TRUE or the String "true".

Parameters:
key A key string.
Returns:
The truth.
 
     public boolean optBoolean(String key) {
         return optBoolean(keyfalse);
     }

    
Get an optional boolean associated with a key. It returns the defaultValue if there is no such key, or if it is not a Boolean or the String "true" or "false" (case insensitive).

Parameters:
key A key string.
defaultValue The default.
Returns:
The truth.
 
     public boolean optBoolean(String keyboolean defaultValue) {
         try {
             return getBoolean(key);
         } catch (Exception e) {
             return defaultValue;
         }
     }

    
Put a key/value pair in the JSONObject, where the value will be a JSONArray which is produced from a Collection.

Parameters:
key A key string.
value A Collection value.
Returns:
this.
Throws:
JSONException
 
     public JSONObject put(String keyCollection valuethrows JSONException {
         put(keynew JSONArray(value));
 
         return this;
     }

    
Get an optional double associated with a key, or NaN if there is no such key or if its value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.

Parameters:
key A string which is the key.
Returns:
An object which is the value.
 
     public double optDouble(String key) {
         return optDouble(key.);
     }

    
Get an optional double associated with a key, or the defaultValue if there is no such key or if its value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.

Parameters:
key A key string.
defaultValue The default.
Returns:
An object which is the value.
 
     public double optDouble(String keydouble defaultValue) {
         try {
             Object o = opt(key);
 
             return (o instanceof Number) ? ((Numbero).doubleValue() : new Double((Stringo).doubleValue();
         } catch (Exception e) {
             return defaultValue;
         }
     }

    
Get an optional int value associated with a key, or zero if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.

Parameters:
key A key string.
Returns:
An object which is the value.
 
     public int optInt(String key) {
         return optInt(key, 0);
     }

    
Get an optional int value associated with a key, or the default if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.

Parameters:
key A key string.
defaultValue The default.
Returns:
An object which is the value.
 
     public int optInt(String keyint defaultValue) {
         try {
             return getInt(key);
         } catch (Exception e) {
             return defaultValue;
         }
     }

    
Get an optional JSONArray associated with a key. It returns null if there is no such key, or if its value is not a JSONArray.

Parameters:
key A key string.
Returns:
A JSONArray which is the value.
 
     public JSONArray optJSONArray(String key) {
         Object o = opt(key);
 
         return (o instanceof JSONArray) ? (JSONArrayo : null;
     }

    
Get an optional JSONObject associated with a key. It returns null if there is no such key, or if its value is not a JSONObject.

Parameters:
key A key string.
Returns:
A JSONObject which is the value.
 
     public JSONObject optJSONObject(String key) {
         Object o = opt(key);
 
         return (o instanceof JSONObject) ? (JSONObjecto : null;
     }

    
Get an optional long value associated with a key, or zero if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.

Parameters:
key A key string.
Returns:
An object which is the value.
 
     public long optLong(String key) {
         return optLong(key, 0);
     }

    
Get an optional long value associated with a key, or the default if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.

Parameters:
key A key string.
defaultValue The default.
Returns:
An object which is the value.
 
     public long optLong(String keylong defaultValue) {
         try {
             return getLong(key);
         } catch (Exception e) {
             return defaultValue;
         }
     }

    
Get an optional string associated with a key. It returns an empty string if there is no such key. If the value is not a string and is not null, then it is coverted to a string.

Parameters:
key A key string.
Returns:
A string which is the value.
 
     public String optString(String key) {
         return optString(key"");
     }

    
Get an optional string associated with a key. It returns the defaultValue if there is no such key.

Parameters:
key A key string.
defaultValue The default.
Returns:
A string which is the value.
 
     public String optString(String keyString defaultValue) {
         Object o = opt(key);
 
         return (o != null) ? o.toString() : defaultValue;
     }

    
Put a key/boolean pair in the JSONObject.

Parameters:
key A key string.
value A boolean which is the value.
Returns:
this.
Throws:
JSONException If the key is null.
 
     public JSONObject put(String keyboolean valuethrows JSONException {
         put(keyvalue ? . : .);
 
         return this;
     }

    
Put a key/double pair in the JSONObject.

Parameters:
key A key string.
value A double which is the value.
Returns:
this.
Throws:
JSONException If the key is null or if the number is invalid.
 
     public JSONObject put(String keydouble valuethrows JSONException {
         put(keynew Double(value));
 
         return this;
     }

    
Put a key/int pair in the JSONObject.

Parameters:
key A key string.
value An int which is the value.
Returns:
this.
Throws:
JSONException If the key is null.
 
     public JSONObject put(String keyint valuethrows JSONException {
         put(keynew Integer(value));
 
         return this;
     }

    
Put a key/long pair in the JSONObject.

Parameters:
key A key string.
value A long which is the value.
Returns:
this.
Throws:
JSONException If the key is null.
 
     public JSONObject put(String keylong valuethrows JSONException {
         put(keynew Long(value));
 
         return this;
     }

    
Put a key/value pair in the JSONObject, where the value will be a JSONObject which is produced from a Map.

Parameters:
key A key string.
value A Map value.
Returns:
this.
Throws:
JSONException
 
     public JSONObject put(String keyMap valuethrows JSONException {
         put(keynew JSONObject(value));
 
         return this;
     }

    
Put a key/value pair in the JSONObject. If the value is null, then the key will be removed from the JSONObject if it is present.

Parameters:
key A key string.
value An object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object.
Returns:
this.
Throws:
JSONException If the value is non-finite number or if the key is null.
 
     public JSONObject put(String keyObject valuethrows JSONException {
         if (key == null) {
             throw new JSONException("Null key.");
         }
 
         if (value != null) {
             testValidity(value);
             this..put(keyvalue);
         } else {
             remove(key);
         }
 
         return this;
     }

    
Put a key/value pair in the JSONObject, but only if the key and the value are both non-null.

Parameters:
key A key string.
value An object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object.
Returns:
this.
Throws:
JSONException If the value is a non-finite number.
 
     public JSONObject putOpt(String keyObject valuethrows JSONException {
         if ((key != null) && (value != null)) {
             put(keyvalue);
         }
 
         return this;
     }

    
Produce a string in double quotes with backslash sequences in all the right places. A backslash will be inserted within </, allowing JSON text to be delivered in HTML. In JSON text, a string cannot contain a control character or an unescaped quote or backslash.

Parameters:
string A String
Returns:
A String correctly formatted for insertion in a JSON text.
 
     public static String quote(String string) {
         if ((string == null) || (string.length() == 0)) {
             return "\"\"";
         }
 
         char b;
         char c = 0;
         int i;
         int len = string.length();
         StringBuffer sb = new StringBuffer(len + 4);
         String t;
 
         sb.append('"');
 
         for (i = 0; i < leni += 1) {
             b = c;
             c = string.charAt(i);
 
             switch (c) {
                 case '\\':
                 case '"':
                     sb.append('\\');
                     sb.append(c);
 
                     break;
 
                 case '/':
                     if (b == '<') {
                         sb.append('\\');
                     }
 
                     sb.append(c);
 
                     break;
 
                 case '\b':
                     sb.append("\\b");
 
                     break;
 
                 case '\t':
                     sb.append("\\t");
 
                     break;
 
                 case '\n':
                     sb.append("\\n");
 
                     break;
 
                 case '\f':
                     sb.append("\\f");
 
                     break;
 
                 case '\r':
                     sb.append("\\r");
 
                     break;
 
                 default:
                     if (c < ' ') {
                         t = "000" + Integer.toHexString(c);
                         sb.append("\\u" + t.substring(t.length() - 4));
                     } else {
                         sb.append(c);
                     }
             }
         }
 
         sb.append('"');
 
         return sb.toString();
     }

    
Remove a name and its value, if present.

Parameters:
key The name to be removed.
Returns:
The value that was associated with the name, or null if there was no value.
 
     public Object remove(String key) {
         return this..remove(key);
     }

    
Throw an exception if the object is an NaN or infinite number.

Parameters:
o The object to test.
Throws:
JSONException If o is a non-finite number.
 
     static void testValidity(Object othrows JSONException {
         if (o != null) {
             if (o instanceof Double) {
                 if (((Doubleo).isInfinite() || ((Doubleo).isNaN()) {
                     throw new JSONException("JSON does not allow non-finite numbers");
                 }
             } else if (o instanceof Float) {
                 if (((Floato).isInfinite() || ((Floato).isNaN()) {
                     throw new JSONException("JSON does not allow non-finite numbers.");
                 }
             }
         }
     }

    
Produce a JSONArray containing the values of the members of this JSONObject.

Parameters:
names A JSONArray containing a list of key strings. This determines the sequence of the values in the result.
Returns:
A JSONArray of values.
Throws:
JSONException If any of the values are non-finite numbers.
 
     public JSONArray toJSONArray(JSONArray namesthrows JSONException {
         if ((names == null) || (names.length() == 0)) {
             return null;
         }
 
         JSONArray ja = new JSONArray();
 
         for (int i = 0; i < names.length(); i += 1) {
             ja.put(this.opt(names.getString(i)));
         }
 
         return ja;
     }

    
Make a JSON text of this JSONObject. For compactness, no whitespace is added. If this would not result in a syntactically correct JSON text, then null will be returned instead.

Warning: This method assumes that the data structure is acyclical.

Returns:
a printable, displayable, portable, transmittable representation of the object, beginning with {  (left brace) and ending with } (right brace).
 
     public String toString() {
         try {
             Iterator keys = keys();
             StringBuffer sb = new StringBuffer("{");
 
             while (keys.hasNext()) {
                 if (sb.length() > 1) {
                     sb.append(',');
                 }
 
                 Object o = keys.next();
 
                 sb.append(quote(o.toString()));
                 sb.append(':');
                 sb.append(valueToString(this..get(o)));
             }
 
             sb.append('}');
 
             return sb.toString();
         } catch (Exception e) {
             return null;
         }
     }

    
Make a prettyprinted JSON text of this JSONObject.

Warning: This method assumes that the data structure is acyclical.

Parameters:
indentFactor The number of spaces to add to each level of indentation.
Returns:
a printable, displayable, portable, transmittable representation of the object, beginning with {  (left brace) and ending with } (right brace).
Throws:
JSONException If the object contains an invalid number.
 
     public String toString(int indentFactorthrows JSONException {
         return toString(indentFactor, 0);
     }

    
Make a prettyprinted JSON text of this JSONObject.

Warning: This method assumes that the data structure is acyclical.

Parameters:
indentFactor The number of spaces to add to each level of indentation.
indent The indentation of the top level.
Returns:
a printable, displayable, transmittable representation of the object, beginning with {  (left brace) and ending with } (right brace).
Throws:
JSONException If the object contains an invalid number.
    String toString(int indentFactorint indentthrows JSONException {
        int i;
        int n = length();
        if (n == 0) {
            return "{}";
        }
        Iterator keys = keys();
        StringBuffer sb = new StringBuffer("{");
        int newindent = indent + indentFactor;
        Object o;
        if (n == 1) {
            o = keys.next();
            sb.append(quote(o.toString()));
            sb.append(": ");
            sb.append(valueToString(this..get(o), indentFactorindent));
        } else {
            while (keys.hasNext()) {
                o = keys.next();
                if (sb.length() > 1) {
                    sb.append(",\n");
                } else {
                    sb.append('\n');
                }
                for (i = 0; i < newindenti += 1) {
                    sb.append(' ');
                }
                sb.append(quote(o.toString()));
                sb.append(": ");
                sb.append(valueToString(this..get(o), indentFactornewindent));
            }
            if (sb.length() > 1) {
                sb.append('\n');
                for (i = 0; i < indenti += 1) {
                    sb.append(' ');
                }
            }
        }
        sb.append('}');
        return sb.toString();
    }

    
Make a JSON text of an Object value. If the object has an value.toJSONString() method, then that method will be used to produce the JSON text. The method is required to produce a strictly conforming text. If the object does not contain a toJSONString method (which is the most common case), then a text will be produced by the rules.

Warning: This method assumes that the data structure is acyclical.

Parameters:
value The value to be serialized.
Returns:
a printable, displayable, transmittable representation of the object, beginning with {  (left brace) and ending with } (right brace).
Throws:
JSONException If the value is or contains an invalid number.
    static String valueToString(Object valuethrows JSONException {
        if ((value == null) || value.equals(null)) {
            return "null";
        }
        if (value instanceof JSONString) {
            Object o;
            try {
                o = ((JSONStringvalue).toJSONString();
            } catch (Exception e) {
                throw new JSONException(e);
            }
            if (o instanceof String) {
                return (Stringo;
            }
            throw new JSONException("Bad value from toJSONString: " + o);
        }
        if (value instanceof Number) {
            return numberToString((Numbervalue);
        }
        if ((value instanceof Boolean) || (value instanceof JSONObject) || (value instanceof JSONArray)) {
            return value.toString();
        }
        return quote(value.toString());
    }

    
Make a prettyprinted JSON text of an object value.

Warning: This method assumes that the data structure is acyclical.

Parameters:
value The value to be serialized.
indentFactor The number of spaces to add to each level of indentation.
indent The indentation of the top level.
Returns:
a printable, displayable, transmittable representation of the object, beginning with {  (left brace) and ending with } (right brace).
Throws:
JSONException If the object contains an invalid number.
    static String valueToString(Object valueint indentFactorint indentthrows JSONException {
        if ((value == null) || value.equals(null)) {
            return "null";
        }
        try {
            if (value instanceof JSONString) {
                Object o = ((JSONStringvalue).toJSONString();
                if (o instanceof String) {
                    return (Stringo;
                }
            }
        } catch (Exception e) {
            /* forget about it */
        }
        if (value instanceof Number) {
            return numberToString((Numbervalue);
        }
        if (value instanceof Boolean) {
            return value.toString();
        }
        if (value instanceof JSONObject) {
            return ((JSONObjectvalue).toString(indentFactorindent);
        }
        if (value instanceof JSONArray) {
            return ((JSONArrayvalue).toString(indentFactorindent);
        }
        return quote(value.toString());
    }

    
Write the contents of the JSONObject as JSON text to a writer. For compactness, no whitespace is added.

Warning: This method assumes that the data structure is acyclical.

Returns:
The writer.
Throws:
JSONException
    public Writer write(Writer writerthrows JSONException {
        try {
            boolean b = false;
            Iterator keys = keys();
            writer.write('{');
            while (keys.hasNext()) {
                if (b) {
                    writer.write(',');
                }
                Object k = keys.next();
                writer.write(quote(k.toString()));
                writer.write(':');
                Object v = this..get(k);
                if (v instanceof JSONObject) {
                    ((JSONObjectv).write(writer);
                } else if (v instanceof JSONArray) {
                    ((JSONArrayv).write(writer);
                } else {
                    writer.write(valueToString(v));
                }
                b = true;
            }
            writer.write('}');
            return writer;
        } catch (IOException e) {
            throw new JSONException(e);
        }
    }

    
JSONObject.NULL is equivalent to the value that JavaScript calls null, whilst Java's null is equivalent to the value that JavaScript calls undefined.
    private static final class Null implements Serializable {
        private static final long serialVersionUID = -1155578668810010644L;
        private Null() {
            super();
        }

        
There is only intended to be a single instance of the NULL object, so the clone method returns itself.

Returns:
NULL.
        @Override
        protected Object clone() {
            return this;
        }

        
A Null object is equal to the null value and to itself.

Parameters:
object An object to test for nullness.
Returns:
true if the object parameter is the JSONObject.NULL object or null.
        @Override
        public boolean equals(Object object) {
            return (object == null) || (object == this);
        }
        @Override
        public int hashCode() {
            return super.hashCode();
        }

        
Get the "null" string value.

Returns:
The string "null".
        @Override
        public String toString() {
            return "null";
        }
        private Object readResolve() throws ObjectStreamException {
            return ;
        }
    }
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