Package net.sf.json

Class JSONObject

java.lang.Object
net.sf.json.JSONObject
All Implemented Interfaces:
Serializable, Comparable, Map<String,Object>, JSON
public final class JSONObject extends Object implements JSON, Map<String,Object>, Comparable
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 JSONNull 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 element 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 coercion 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 syntax 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:
JSON.org
See Also:

  • Constructor Details

    • JSONObject

      public JSONObject()
      Construct an empty JSONObject.

    • JSONObject

      public JSONObject(boolean isNull)
      Creates a JSONObject that is null.

  • Method Details

    • fromObject

      public static JSONObject fromObject(Object object)
      Creates a JSONObject.
      Inspects the object type to call the correct JSONObject factory method. Accepts JSON formatted strings, Maps, DynaBeans and JavaBeans.
      Parameters:
      object -
      Throws:
      JSONException - if the object can not be converted to a proper JSONObject.

    • fromObject

      public static JSONObject fromObject(Object object, JsonConfig jsonConfig)
      Creates a JSONObject.
      Inspects the object type to call the correct JSONObject factory method. Accepts JSON formatted strings, Maps, DynaBeans and JavaBeans.
      Parameters:
      object -
      Throws:
      JSONException - if the object can not be converted to a proper JSONObject.

    • toBean

      public Object toBean()
      Creates a JSONDynaBean from a JSONObject.

    • toBean

      public static Object toBean(JSONObject jsonObject)

    • toBean

      public Object toBean(Class beanClass)

    • toBean

      public static Object toBean(JSONObject jsonObject, Class beanClass)
      Creates a bean from a JSONObject, with a specific target class.

    • toBean

      public static Object toBean(JSONObject jsonObject, Class beanClass, Map classMap)
      Creates a bean from a JSONObject, with a specific target class.
      If beanClass is null, this method will return a graph of DynaBeans. Any attribute that is a JSONObject and matches a key in the classMap will be converted to that target class.
      The classMap has the following conventions:
      • Every key must be an String.
      • Every value must be a Class.
      • A key may be a regular expression.

    • toBean

      public static Object toBean(JSONObject jsonObject, JsonConfig jsonConfig)
      Creates a bean from a JSONObject, with the specific configuration.

    • toBean

      public static Object toBean(JSONObject jsonObject, Object bean, JsonConfig jsonConfig)
      Creates a bean from a JSONObject, with the specific configuration.

    • accumulate

      public JSONObject accumulate(String key, boolean value)
      Accumulate values under a key. It is similar to the element 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 replace 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.

    • accumulate

      public JSONObject accumulate(String key, double value)
      Accumulate values under a key. It is similar to the element 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 replace 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.

    • accumulate

      public JSONObject accumulate(String key, int value)
      Accumulate values under a key. It is similar to the element 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 replace 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.

    • accumulate

      public JSONObject accumulate(String key, long value)
      Accumulate values under a key. It is similar to the element 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 replace 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.

    • accumulate

      public JSONObject accumulate(String key, Object value)
      Accumulate values under a key. It is similar to the element 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 replace 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.

    • accumulate

      public JSONObject accumulate(String key, Object value, JsonConfig jsonConfig)
      Accumulate values under a key. It is similar to the element 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 replace 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.

    • accumulateAll

      public void accumulateAll(Map map)

    • accumulateAll

      public void accumulateAll(Map map, JsonConfig jsonConfig)

    • clear

      public void clear()
      Specified by:
      clear in interface Map<String,Object>

    • compareTo

      public int compareTo(Object obj)
      Specified by:
      compareTo in interface Comparable

    • containsKey

      public boolean containsKey(Object key)
      Specified by:
      containsKey in interface Map<String,Object>

    • containsValue

      public boolean containsValue(Object value)
      Specified by:
      containsValue in interface Map<String,Object>

    • containsValue

      public boolean containsValue(Object value, JsonConfig jsonConfig)

    • discard

      public JSONObject discard(String key)
      Remove a name and its value, if present.
      Parameters:
      key - A key string.
      Returns:
      this.

    • element

      public JSONObject element(String key, boolean value)
      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.

    • element

      public JSONObject element(String key, Collection value)
      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

    • element

      public JSONObject element(String key, Collection value, JsonConfig jsonConfig)
      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

    • element

      public JSONObject element(String key, double value)
      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.

    • element

      public JSONObject element(String key, int value)
      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.

    • element

      public JSONObject element(String key, long value)
      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.

    • element

      public JSONObject element(String key, Map value)
      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

    • element

      public JSONObject element(String key, Map value, JsonConfig jsonConfig)
      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

    • element

      public JSONObject element(String key, Object value)
      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.
      If there is a previous value assigned to the key, it will call accumulate.
      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 JSONNull object.
      Returns:
      this.
      Throws:
      JSONException - If the value is non-finite number or if the key is null.

    • element

      public JSONObject element(String key, Object value, JsonConfig jsonConfig)
      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.
      If there is a previous value assigned to the key, it will call accumulate.
      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 JSONNull object.
      Returns:
      this.
      Throws:
      JSONException - If the value is non-finite number or if the key is null.

    • elementOpt

      public JSONObject elementOpt(String key, Object value)
      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 JSONNull object.
      Returns:
      this.
      Throws:
      JSONException - If the value is a non-finite number.

    • elementOpt

      public JSONObject elementOpt(String key, Object value, JsonConfig jsonConfig)
      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 JSONNull object.
      Returns:
      this.
      Throws:
      JSONException - If the value is a non-finite number.

    • entrySet

      public Set entrySet()
      Specified by:
      entrySet in interface Map<String,Object>

    • equals

      public boolean equals(Object obj)
      Specified by:
      equals in interface Map<String,Object>
      Overrides:
      equals in class Object

    • get

      public Object get(Object key)
      Specified by:
      get in interface Map<String,Object>

    • get

      public Object get(String key)
      Get the value object associated with a key.
      Parameters:
      key - A key string.
      Returns:
      The object associated with the key.
      Throws:
      JSONException - if this.isNull() returns true.

    • getBoolean

      public boolean getBoolean(String key)
      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".

    • getDouble

      public double getDouble(String key)
      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.

    • getInt

      public int getInt(String key)
      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.

    • getJSONArray

      public JSONArray getJSONArray(String 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.

    • getJSONObject

      public JSONObject getJSONObject(String key)
      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.

    • getLong

      public long getLong(String key)
      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.

    • getString

      public String getString(String 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.

    • has

      public boolean has(String key)
      Determine if the JSONObject contains a specific key.
      Parameters:
      key - A key string.
      Returns:
      true if the key exists in the JSONObject.

    • hashCode

      public int hashCode()
      Specified by:
      hashCode in interface Map<String,Object>
      Overrides:
      hashCode in class Object

    • isArray

      public boolean isArray()
      Description copied from interface: JSON
      Returns true if this object is a JSONArray, false otherwise.
      Specified by:
      isArray in interface JSON

    • isEmpty

      public boolean isEmpty()
      Description copied from interface: JSON
      Returns true if this object has no elements or keys.
      Specified by:
      isEmpty in interface JSON
      Specified by:
      isEmpty in interface Map<String,Object>

    • isNullObject

      public boolean isNullObject()
      Returs if this object is a null JSONObject.

    • keys

      public Iterator<String> keys()
      Get an enumeration of the keys of the JSONObject.
      Returns:
      An iterator of the keys.

    • keySet

      public Set<String> keySet()
      Specified by:
      keySet in interface Map<String,Object>

    • names

      public JSONArray names()
      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.

    • names

      public JSONArray names(JsonConfig jsonConfig)
      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.

    • opt

      public Object opt(String key)
      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.

    • optBoolean

      public boolean optBoolean(String 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.

    • optBoolean

      public boolean optBoolean(String key, boolean defaultValue)
      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.

    • optDouble

      public double optDouble(String key)
      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.

    • optDouble

      public double optDouble(String key, double defaultValue)
      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.

    • optInt

      public int optInt(String key)
      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.

    • optInt

      public int optInt(String key, int defaultValue)
      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.

    • optJSONArray

      public JSONArray optJSONArray(String key)
      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.

    • optJSONObject

      public JSONObject optJSONObject(String key)
      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.

    • optLong

      public long optLong(String key)
      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.

    • optLong

      public long optLong(String key, long defaultValue)
      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.

    • optString

      public String optString(String key)
      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.

    • optString

      public String optString(String key, String defaultValue)
      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.

    • put

      public Object put(String key, Object value)
      Specified by:
      put in interface Map<String,Object>

    • putAll

      public void putAll(Map map)
      Specified by:
      putAll in interface Map<String,Object>

    • putAll

      public void putAll(Map map, JsonConfig jsonConfig)

    • remove

      public Object remove(Object key)
      Specified by:
      remove in interface Map<String,Object>

    • remove

      public Object remove(String key)
      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.

    • size

      public int size()
      Get the number of keys stored in the JSONObject.
      Specified by:
      size in interface JSON
      Specified by:
      size in interface Map<String,Object>
      Returns:
      The number of keys in the JSONObject.

    • toJSONArray

      public JSONArray toJSONArray(JSONArray names)
      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.

    • toString

      public String toString()
      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.

      Overrides:
      toString in class Object
      Returns:
      a printable, displayable, portable, transmittable representation of the object, beginning with { (left brace) and ending with } (right brace).

    • toString

      public String toString(int indentFactor)
      Make a prettyprinted JSON text of this JSONObject.

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

      Specified by:
      toString in interface JSON
      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.

    • toString

      public String toString(int indentFactor, int indent)
      Make a prettyprinted JSON text of this JSONObject.

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

      Specified by:
      toString in interface JSON
      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.

    • values

      public Collection values()
      Specified by:
      values in interface Map<String,Object>

    • write

      protected void write(Writer writer, net.sf.json.AbstractJSON.WritingVisitor visitor) throws IOException
      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.

      Throws:
      JSONException
      IOException

    • _processValue

      protected Object _processValue(Object value, JsonConfig jsonConfig)

    • addInstance

      protected static boolean addInstance(Object instance)
      Adds a reference for cycle detection check.
      Parameters:
      instance - the reference to add
      Returns:
      true if the instance has not been added previously, false otherwise.

    • fireArrayEndEvent

      protected static void fireArrayEndEvent(JsonConfig jsonConfig)
      Fires an end of array event.

    • fireArrayStartEvent

      protected static void fireArrayStartEvent(JsonConfig jsonConfig)
      Fires a start of array event.

    • fireElementAddedEvent

      protected static void fireElementAddedEvent(int index, Object element, JsonConfig jsonConfig)
      Fires an element added event.
      Parameters:
      index - the index where the element was added
      element - the added element

    • fireErrorEvent

      protected static void fireErrorEvent(JSONException jsone, JsonConfig jsonConfig)
      Fires an error event.
      Parameters:
      jsone - the thrown exception

    • fireObjectEndEvent

      protected static void fireObjectEndEvent(JsonConfig jsonConfig)
      Fires an end of object event.

    • fireObjectStartEvent

      protected static void fireObjectStartEvent(JsonConfig jsonConfig)
      Fires a start of object event.

    • firePropertySetEvent

      protected static void firePropertySetEvent(String key, Object value, boolean accumulated, JsonConfig jsonConfig)
      Fires a property set event.
      Parameters:
      key - the name of the property
      value - the value of the property
      accumulated - if the value has been accumulated over 'key'

    • fireWarnEvent

      protected static void fireWarnEvent(String warning, JsonConfig jsonConfig)
      Fires a warning event.
      Parameters:
      warning - the warning message

    • removeInstance

      protected static void removeInstance(Object instance)
      Removes a reference for cycle detection check.

    • write

      public final Writer write(Writer writer) throws IOException
      Description copied from interface: JSON
      Write the contents as JSON text to a writer. For compactness, no whitespace is added.

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

      Specified by:
      write in interface JSON
      Returns:
      The writer.
      Throws:
      IOException

    • writeCanonical

      public final Writer writeCanonical(Writer writer) throws IOException
      Description copied from interface: JSON
      Writes the canonicalized form of this JSON object.
      Specified by:
      writeCanonical in interface JSON
      Throws:
      IOException