Class JSONObject

  • All Implemented Interfaces:
    java.io.Serializable

    public class JSONObject
    extends java.lang.Object
    implements java.io.Serializable
    A modifiable set of name/value mappings. Names are unique, non-null strings. Values may be any mix of JSONObjects, JSONArrays, Strings, Booleans, Integers, Longs, Doubles or NULL. Values may not be null, NaNs, infinities, or of any type not listed here.

    This class can coerce values to another type when requested.

    This class can look up both mandatory and optional values:

    • Use getType() to retrieve a mandatory value. This fails with a JSONException if the requested name has no value or if the value cannot be coerced to the requested type.
    • Use optType() to retrieve an optional value. This returns a system- or user-supplied default if the requested name has no value or if the value cannot be coerced to the requested type.

    Warning: this class represents null in two incompatible ways: the standard Java null reference, and the sentinel value NULL. In particular, calling put(name, null) removes the named entry from the object but put(name, JSONObject.NULL) stores an entry whose value is JSONObject.NULL.

    Instances of this class are not thread safe. Although this class is nonfinal, it was not designed for inheritance and should not be subclassed. In particular, self-use by overrideable methods is not specified. See Effective Java Item 17, "Design and Document or inheritance or else prohibit it" for further information.

    See Also:
    Serialized Form
    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.lang.Object NULL
      A sentinel value used to explicitly define a name with no value.
    • Constructor Summary

      Constructors 
      Constructor Description
      JSONObject()
      Creates a JSONObject with no name/value mappings.
      JSONObject​(JSONObject copyFrom)
      Creates a new JSONObject by copying mappings for given object
      JSONObject​(JSONObject copyFrom, java.lang.String[] names)
      Creates a new JSONObject by copying mappings for the listed names from the given object.
      JSONObject​(JSONTokener readFrom)
      Creates a new JSONObject with name/value mappings from the next object in the tokener.
      JSONObject​(java.lang.String json)
      Creates a new JSONObject with name/value mappings from the JSON string.
      JSONObject​(java.util.Map copyFrom)
      Creates a new JSONObject by copying all name/value mappings from the given map.
    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      JSONObject accumulate​(java.lang.String name, java.lang.Object value)
      Appends value to the array already mapped to name.
      java.lang.Object get​(java.lang.String name)
      Returns the value mapped by name, or throws if no such mapping exists.
      boolean getBoolean​(java.lang.String name)
      Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or throws otherwise.
      double getDouble​(java.lang.String name)
      Returns the value mapped by name if it exists and is a double or can be coerced to a double, or throws otherwise.
      int getInt​(java.lang.String name)
      Returns the value mapped by name if it exists and is an int or can be coerced to an int, or throws otherwise.
      JSONArray getJSONArray​(java.lang.String name)
      Returns the value mapped by name if it exists and is a JSONArray, or throws otherwise.
      JSONObject getJSONObject​(java.lang.String name)
      Returns the value mapped by name if it exists and is a JSONObject, or throws otherwise.
      long getLong​(java.lang.String name)
      Returns the value mapped by name if it exists and is a long or can be coerced to a long, or throws otherwise.
      java.lang.String getString​(java.lang.String name)
      Returns the value mapped by name if it exists, coercing it if necessary, or throws if no such mapping exists.
      boolean has​(java.lang.String name)
      Returns true if this object has a mapping for name.
      boolean hasNonNull​(java.lang.String name)
      Returns true if this object has a mapping for name.
      boolean isNull​(java.lang.String name)
      Returns true if this object has no mapping for name or if it has a mapping whose value is NULL.
      java.util.Iterator<java.lang.String> keys()
      Returns an iterator of the String names in this object.
      int length()
      Returns the number of name/value mappings in this object.
      JSONArray names()
      Returns an array containing the string names in this object.
      static java.lang.String numberToString​(java.lang.Number number)
      Encodes the number as a JSON string.
      java.lang.Object opt​(java.lang.String name)
      Returns the value mapped by name, or null if no such mapping exists.
      boolean optBoolean​(java.lang.String name)
      Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or false otherwise.
      boolean optBoolean​(java.lang.String name, boolean fallback)
      Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or fallback otherwise.
      double optDouble​(java.lang.String name)
      Returns the value mapped by name if it exists and is a double or can be coerced to a double, or NaN otherwise.
      double optDouble​(java.lang.String name, double fallback)
      Returns the value mapped by name if it exists and is a double or can be coerced to a double, or fallback otherwise.
      int optInt​(java.lang.String name)
      Returns the value mapped by name if it exists and is an int or can be coerced to an int, or 0 otherwise.
      int optInt​(java.lang.String name, int fallback)
      Returns the value mapped by name if it exists and is an int or can be coerced to an int, or fallback otherwise.
      JSONArray optJSONArray​(java.lang.String name)
      Returns the value mapped by name if it exists and is a JSONArray, or null otherwise.
      JSONObject optJSONObject​(java.lang.String name)
      Returns the value mapped by name if it exists and is a JSONObject, or null otherwise.
      long optLong​(java.lang.String name)
      Returns the value mapped by name if it exists and is a long or can be coerced to a long, or 0 otherwise.
      long optLong​(java.lang.String name, long fallback)
      Returns the value mapped by name if it exists and is a long or can be coerced to a long, or fallback otherwise.
      java.lang.String optString​(java.lang.String name)
      Returns the value mapped by name if it exists, coercing it if necessary, or the empty string if no such mapping exists.
      java.lang.String optString​(java.lang.String name, java.lang.String fallback)
      Returns the value mapped by name if it exists, coercing it if necessary, or fallback if no such mapping exists.
      JSONObject put​(java.lang.String name, boolean value)
      Maps name to value, clobbering any existing name/value mapping with the same name.
      JSONObject put​(java.lang.String name, double value)
      Maps name to value, clobbering any existing name/value mapping with the same name.
      JSONObject put​(java.lang.String name, int value)
      Maps name to value, clobbering any existing name/value mapping with the same name.
      JSONObject put​(java.lang.String name, long value)
      Maps name to value, clobbering any existing name/value mapping with the same name.
      JSONObject put​(java.lang.String name, java.lang.Object value)
      Maps name to value, clobbering any existing name/value mapping with the same name.
      JSONObject putOpt​(java.lang.String name, java.lang.Object value)
      Equivalent to put(name, value) when both parameters are non-null; does nothing otherwise.
      static java.lang.String quote​(java.lang.String data)
      Encodes data as a JSON string.
      java.lang.Boolean reallyOptBoolean​(java.lang.String name, java.lang.Boolean fallback)
      Returns the value mapped by name if it exists and is not null, coercing it if necessary, or fallback if no such mapping exists or is null.
      java.lang.Double reallyOptDouble​(java.lang.String name, java.lang.Double fallback)
      Returns the value mapped by name if it exists and is not null, coercing it if necessary, or fallback if no such mapping exists or is null.
      java.lang.Integer reallyOptInteger​(java.lang.String name, java.lang.Integer fallback)
      Returns the value mapped by name if it exists and is not null, coercing it if necessary, or fallback if no such mapping exists or is null.
      java.lang.Long reallyOptLong​(java.lang.String name, java.lang.Long fallback)
      Returns the value mapped by name if it exists and is not null, coercing it if necessary, or fallback if no such mapping exists or is null.
      java.lang.String reallyOptString​(java.lang.String name, java.lang.String fallback)
      Returns the value mapped by name if it exists and is not null, coercing it if necessary, or fallback if no such mapping exists or is null.
      java.lang.Object remove​(java.lang.String name)
      Removes the named mapping if it exists; does nothing otherwise.
      JSONArray toJSONArray​(JSONArray names)
      Returns an array with the values corresponding to names.
      java.lang.String toString()
      Encodes this object as a compact JSON string, such as:
      java.lang.String toString​(int indentSpaces)
      Encodes this object as a human readable JSON string for debugging, such as:
      static java.lang.Object wrap​(java.lang.Object o)
      Wraps the given object if necessary.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Field Detail

      • NULL

        public static final java.lang.Object NULL
        A sentinel value used to explicitly define a name with no value. Unlike null, names with this value:

        This value violates the general contract of Object#equals by returning true when compared to null. Its toString() method returns "null".

    • Constructor Detail

      • JSONObject

        public JSONObject()
        Creates a JSONObject with no name/value mappings.
      • JSONObject

        public JSONObject​(java.util.Map copyFrom)
        Creates a new JSONObject by copying all name/value mappings from the given map.
        Parameters:
        copyFrom - a map whose keys are of type String and whose values are of supported types.
        Throws:
        java.lang.NullPointerException - if any of the map's keys are null.
      • JSONObject

        public JSONObject​(JSONTokener readFrom)
                   throws JSONException
        Creates a new JSONObject with name/value mappings from the next object in the tokener.
        Parameters:
        readFrom - a tokener whose nextValue() method will yield a JSONObject.
        Throws:
        JSONException - if the parse fails or doesn't yield a JSONObject.
      • JSONObject

        public JSONObject​(java.lang.String json)
                   throws JSONException
        Creates a new JSONObject with name/value mappings from the JSON string.
        Parameters:
        json - a JSON-encoded string containing an object.
        Throws:
        JSONException - if the parse fails or doesn't yield a JSONObject.
      • JSONObject

        public JSONObject​(JSONObject copyFrom,
                          java.lang.String[] names)
                   throws JSONException
        Creates a new JSONObject by copying mappings for the listed names from the given object. Names that aren't present in copyFrom will be skipped.
        Throws:
        JSONException
    • Method Detail

      • length

        public int length()
        Returns the number of name/value mappings in this object.
      • put

        public JSONObject put​(java.lang.String name,
                              boolean value)
                       throws JSONException
        Maps name to value, clobbering any existing name/value mapping with the same name.
        Returns:
        this object.
        Throws:
        JSONException
      • put

        public JSONObject put​(java.lang.String name,
                              double value)
                       throws JSONException
        Maps name to value, clobbering any existing name/value mapping with the same name.
        Parameters:
        value - a finite value. May not be NaNs or infinities.
        Returns:
        this object.
        Throws:
        JSONException
      • put

        public JSONObject put​(java.lang.String name,
                              int value)
                       throws JSONException
        Maps name to value, clobbering any existing name/value mapping with the same name.
        Returns:
        this object.
        Throws:
        JSONException
      • put

        public JSONObject put​(java.lang.String name,
                              long value)
                       throws JSONException
        Maps name to value, clobbering any existing name/value mapping with the same name.
        Returns:
        this object.
        Throws:
        JSONException
      • put

        public JSONObject put​(java.lang.String name,
                              java.lang.Object value)
                       throws JSONException
        Maps name to value, clobbering any existing name/value mapping with the same name. If the value is null, any existing mapping for name is removed.
        Parameters:
        value - a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL, or null. May not be NaNs or infinities.
        Returns:
        this object.
        Throws:
        JSONException
      • putOpt

        public JSONObject putOpt​(java.lang.String name,
                                 java.lang.Object value)
                          throws JSONException
        Equivalent to put(name, value) when both parameters are non-null; does nothing otherwise.
        Throws:
        JSONException
      • accumulate

        public JSONObject accumulate​(java.lang.String name,
                                     java.lang.Object value)
                              throws JSONException
        Appends value to the array already mapped to name. If this object has no mapping for name, this inserts a new mapping. If the mapping exists but its value is not an array, the existing and new values are inserted in order into a new array which is itself mapped to name. In aggregate, this allows values to be added to a mapping one at a time.

        Note that append(String, Object) provides better semantics. In particular, the mapping for name will always be a JSONArray. Using accumulate will result in either a JSONArray or a mapping whose type is the type of value depending on the number of calls to it.

        Parameters:
        value - a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL or null. May not be NaNs or infinities.
        Throws:
        JSONException
      • remove

        public java.lang.Object remove​(java.lang.String name)
        Removes the named mapping if it exists; does nothing otherwise.
        Returns:
        the value previously mapped by name, or null if there was no such mapping.
      • isNull

        public boolean isNull​(java.lang.String name)
        Returns true if this object has no mapping for name or if it has a mapping whose value is NULL.
      • has

        public boolean has​(java.lang.String name)
        Returns true if this object has a mapping for name. The mapping may be NULL.
      • hasNonNull

        public boolean hasNonNull​(java.lang.String name)
        Returns true if this object has a mapping for name. The mapping CANNOT be NULL.
      • get

        public java.lang.Object get​(java.lang.String name)
                             throws JSONException
        Returns the value mapped by name, or throws if no such mapping exists.
        Throws:
        JSONException - if no such mapping exists.
      • opt

        public java.lang.Object opt​(java.lang.String name)
        Returns the value mapped by name, or null if no such mapping exists.
      • getBoolean

        public boolean getBoolean​(java.lang.String name)
                           throws JSONException
        Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or throws otherwise.
        Throws:
        JSONException - if the mapping doesn't exist or cannot be coerced to a boolean.
      • optBoolean

        public boolean optBoolean​(java.lang.String name)
        Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or false otherwise.
      • optBoolean

        public boolean optBoolean​(java.lang.String name,
                                  boolean fallback)
        Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or fallback otherwise.
      • reallyOptBoolean

        public java.lang.Boolean reallyOptBoolean​(java.lang.String name,
                                                  java.lang.Boolean fallback)
        Returns the value mapped by name if it exists and is not null, coercing it if necessary, or fallback if no such mapping exists or is null.
      • getDouble

        public double getDouble​(java.lang.String name)
                         throws JSONException
        Returns the value mapped by name if it exists and is a double or can be coerced to a double, or throws otherwise.
        Throws:
        JSONException - if the mapping doesn't exist or cannot be coerced to a double.
      • optDouble

        public double optDouble​(java.lang.String name)
        Returns the value mapped by name if it exists and is a double or can be coerced to a double, or NaN otherwise.
      • optDouble

        public double optDouble​(java.lang.String name,
                                double fallback)
        Returns the value mapped by name if it exists and is a double or can be coerced to a double, or fallback otherwise.
      • reallyOptDouble

        public java.lang.Double reallyOptDouble​(java.lang.String name,
                                                java.lang.Double fallback)
        Returns the value mapped by name if it exists and is not null, coercing it if necessary, or fallback if no such mapping exists or is null.
      • getInt

        public int getInt​(java.lang.String name)
                   throws JSONException
        Returns the value mapped by name if it exists and is an int or can be coerced to an int, or throws otherwise.
        Throws:
        JSONException - if the mapping doesn't exist or cannot be coerced to an int.
      • optInt

        public int optInt​(java.lang.String name)
        Returns the value mapped by name if it exists and is an int or can be coerced to an int, or 0 otherwise.
      • optInt

        public int optInt​(java.lang.String name,
                          int fallback)
        Returns the value mapped by name if it exists and is an int or can be coerced to an int, or fallback otherwise.
      • reallyOptInteger

        public java.lang.Integer reallyOptInteger​(java.lang.String name,
                                                  java.lang.Integer fallback)
        Returns the value mapped by name if it exists and is not null, coercing it if necessary, or fallback if no such mapping exists or is null.
      • getLong

        public long getLong​(java.lang.String name)
                     throws JSONException
        Returns the value mapped by name if it exists and is a long or can be coerced to a long, or throws otherwise. Note that JSON represents numbers as doubles, so this is lossy; use strings to transfer numbers via JSON.
        Throws:
        JSONException - if the mapping doesn't exist or cannot be coerced to a long.
      • reallyOptLong

        public java.lang.Long reallyOptLong​(java.lang.String name,
                                            java.lang.Long fallback)
        Returns the value mapped by name if it exists and is not null, coercing it if necessary, or fallback if no such mapping exists or is null.
      • optLong

        public long optLong​(java.lang.String name)
        Returns the value mapped by name if it exists and is a long or can be coerced to a long, or 0 otherwise. Note that JSON represents numbers as doubles, so this is lossy; use strings to transfer numbers via JSON.
      • optLong

        public long optLong​(java.lang.String name,
                            long fallback)
        Returns the value mapped by name if it exists and is a long or can be coerced to a long, or fallback otherwise. Note that JSON represents numbers as doubles, so this is lossy; use strings to transfer numbers via JSON.
      • getString

        public java.lang.String getString​(java.lang.String name)
                                   throws JSONException
        Returns the value mapped by name if it exists, coercing it if necessary, or throws if no such mapping exists.
        Throws:
        JSONException - if no such mapping exists.
      • optString

        public java.lang.String optString​(java.lang.String name)
        Returns the value mapped by name if it exists, coercing it if necessary, or the empty string if no such mapping exists.
      • optString

        public java.lang.String optString​(java.lang.String name,
                                          java.lang.String fallback)
        Returns the value mapped by name if it exists, coercing it if necessary, or fallback if no such mapping exists.
      • reallyOptString

        public java.lang.String reallyOptString​(java.lang.String name,
                                                java.lang.String fallback)
        Returns the value mapped by name if it exists and is not null, coercing it if necessary, or fallback if no such mapping exists or is null.
      • getJSONArray

        public JSONArray getJSONArray​(java.lang.String name)
                               throws JSONException
        Returns the value mapped by name if it exists and is a JSONArray, or throws otherwise.
        Throws:
        JSONException - if the mapping doesn't exist or is not a JSONArray.
      • optJSONArray

        public JSONArray optJSONArray​(java.lang.String name)
        Returns the value mapped by name if it exists and is a JSONArray, or null otherwise.
      • getJSONObject

        public JSONObject getJSONObject​(java.lang.String name)
                                 throws JSONException
        Returns the value mapped by name if it exists and is a JSONObject, or throws otherwise.
        Throws:
        JSONException - if the mapping doesn't exist or is not a JSONObject.
      • optJSONObject

        public JSONObject optJSONObject​(java.lang.String name)
        Returns the value mapped by name if it exists and is a JSONObject, or null otherwise.
      • toJSONArray

        public JSONArray toJSONArray​(JSONArray names)
                              throws JSONException
        Returns an array with the values corresponding to names. The array contains null for names that aren't mapped. This method returns null if names is either null or empty.
        Throws:
        JSONException
      • keys

        public java.util.Iterator<java.lang.String> keys()
        Returns an iterator of the String names in this object. The returned iterator supports remove, which will remove the corresponding mapping from this object. If this object is modified after the iterator is returned, the iterator's behavior is undefined. The order of the keys is undefined.
      • names

        public JSONArray names()
        Returns an array containing the string names in this object. This method returns null if this object contains no mappings.
      • toString

        public java.lang.String toString()
        Encodes this object as a compact JSON string, such as:
        {"query":"Pizza","locations":[94043,90210]}
        Overrides:
        toString in class java.lang.Object
      • toString

        public java.lang.String toString​(int indentSpaces)
                                  throws JSONException
        Encodes this object as a human readable JSON string for debugging, such as:
         {
             "query": "Pizza",
             "locations": [
                 94043,
                 90210
             ]
         }
        Parameters:
        indentSpaces - the number of spaces to indent for each level of nesting.
        Throws:
        JSONException
      • numberToString

        public static java.lang.String numberToString​(java.lang.Number number)
                                               throws JSONException
        Encodes the number as a JSON string.
        Parameters:
        number - a finite value. May not be NaNs or infinities.
        Throws:
        JSONException
      • quote

        public static java.lang.String quote​(java.lang.String data)
        Encodes data as a JSON string. This applies quotes and any necessary character escaping.
        Parameters:
        data - the string to encode. Null will be interpreted as an empty string.
      • wrap

        public static java.lang.Object wrap​(java.lang.Object o)
        Wraps the given object if necessary.

        If the object is null or , returns NULL. If the object is a JSONArray or JSONObject, no wrapping is necessary. If the object is NULL, no wrapping is necessary. If the object is an array or Collection, returns an equivalent JSONArray. If the object is a Map, returns an equivalent JSONObject. If the object is a primitive wrapper type or String, returns the object. Otherwise if the object is from a java package, returns the result of toString. If wrapping fails, returns null.