Package com.github.openjson

Class JSONObject

java.lang.Object
com.github.openjson.JSONObject
public class JSONObject extends Object
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.

  • When the requested type is a boolean, strings will be coerced using a case-insensitive comparison to "true" and "false".
  • When the requested type is a double, other Number types will be coerced using doubleValue. Strings that can be coerced using Double.valueOf(String) will be.
  • When the requested type is an int, other Number types will be coerced using intValue. Strings that can be coerced using Double.valueOf(String) will be, and then cast to int.
  • When the requested type is a long, other Number types will be coerced using longValue. Strings that can be coerced using Double.valueOf(String) will be, and then cast to long. This two-step conversion is lossy for very large values. For example, the string "9223372036854775806" yields the long 9223372036854775807.
  • When the requested type is a String, other non-null values will be coerced using String.valueOf(Object). Although null cannot be coerced, the sentinel value NULL is coerced to the string "null".

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.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final LinkedHashMap<String,Object>
    nameValuePairs
     
    private static final Double
    NEGATIVE_ZERO
     
    static final 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, 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(Object bean)
    Creates a json object from a bean
    JSONObject(String json)
    Creates a new JSONObject with name/value mappings from the JSON string.
    JSONObject(Map copyFrom)
    Creates a new JSONObject by copying all name/value mappings from the given map.

  • Method Summary

    Modifier and Type
    Method
    Description
    JSONObject
    accumulate(String name, Object value)
    Appends value to the array already mapped to name.
    JSONObject
    append(String name, Object value)
    Appends values to the array mapped to name.
    (package private) String
    checkName(String name)
     
    protected void
    encode(JSONStringer stringer)
    Encodes this object using JSONStringer provided
    Object
    get(String name)
    Returns the value mapped by name, or throws if no such mapping exists.
    boolean
    getBoolean(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(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(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(String name)
    Returns the value mapped by name if it exists and is a JSONArray, or throws otherwise.
    JSONObject
    getJSONObject(String name)
    Returns the value mapped by name if it exists and is a JSONObject, or throws otherwise.
    long
    getLong(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.
    static String[]
    getNames(JSONObject x)
     
    String
    getString(String name)
    Returns the value mapped by name if it exists, coercing it if necessary, or throws if no such mapping exists.
    boolean
    has(String name)
    Returns true if this object has a mapping for name.
    private void
    init(JSONTokener readFrom)
     
    private void
    init(Map copyFrom)
     
    boolean
    isNull(String name)
    Returns true if this object has no mapping for name or if it has a mapping whose value is NULL.
    Iterator<String>
    keys()
    Returns an iterator of the String names in this object.
    Set<String>
    keySet()
    Returns the set of 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 String
    numberToString(Number number)
    Encodes the number as a JSON string.
    static Map<String,Object>
    objectAsMap(Object bean)
    Creates a name-value map from a bean
    Object
    opt(String name)
    Returns the value mapped by name, or null if no such mapping exists.
    boolean
    optBoolean(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(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(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(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(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(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(String name)
    Returns the value mapped by name if it exists and is a JSONArray, or null otherwise.
    JSONObject
    optJSONObject(String name)
    Returns the value mapped by name if it exists and is a JSONObject, or null otherwise.
    long
    optLong(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(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.
    String
    optString(String name)
    Returns the value mapped by name if it exists, coercing it if necessary, or the empty string if no such mapping exists.
    String
    optString(String name, String fallback)
    Returns the value mapped by name if it exists, coercing it if necessary, or fallback if no such mapping exists.
    JSONObject
    put(String name, boolean value)
    Maps name to value, clobbering any existing name/value mapping with the same name.
    JSONObject
    put(String name, double value)
    Maps name to value, clobbering any existing name/value mapping with the same name.
    JSONObject
    put(String name, int value)
    Maps name to value, clobbering any existing name/value mapping with the same name.
    JSONObject
    put(String name, long value)
    Maps name to value, clobbering any existing name/value mapping with the same name.
    JSONObject
    put(String name, Object value)
    Maps name to value, clobbering any existing name/value mapping with the same name.
    JSONObject
    putOpt(String name, Object value)
    Equivalent to put(name, value) when both parameters are non-null; does nothing otherwise.
    static String
    quote(String data)
    Encodes data as a JSON string.
    Object
    remove(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.
    String
    toString()
    Encodes this object as a compact JSON string, such as:
    String
    toString(int indentSpaces)
    Encodes this object as a human readable JSON string for debugging, such as:
    String
    toString(JSONStringer stringer)
    Encodes this object using JSONStringer provided
    static Object
    wrap(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 Details

    • NEGATIVE_ZERO

      private static final Double NEGATIVE_ZERO

    • NULL

      public static final 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(java.lang.Object) by returning true when compared to null. Its toString() method returns "null".

    • nameValuePairs

      private final LinkedHashMap<String,Object> nameValuePairs

  • Constructor Details

    • JSONObject

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

    • JSONObject

      public JSONObject(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:
      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(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, 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.
      Parameters:
      copyFrom - The source object.
      names - The names of the fields to copy.
      Throws:
      JSONException - On internal errors. Shouldn't happen.

    • JSONObject

      public JSONObject(Object bean) throws JSONException
      Creates a json object from a bean
      Parameters:
      bean - the bean to create the json object from
      Throws:
      JSONException - If there is an exception while reading the bean

  • Method Details

    • init

      private void init(JSONTokener readFrom)

    • init

      private void init(Map copyFrom)

    • objectAsMap

      public static Map<String,Object> objectAsMap(Object bean) throws JSONException
      Creates a name-value map from a bean
      Parameters:
      bean - the bean to create the map from
      Returns:
      name-value map representing the bean
      Throws:
      JSONException - If there is an exception while reading the bean

    • getNames

      public static String[] getNames(JSONObject x)

    • length

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

    • put

      public JSONObject put(String name, boolean value) throws JSONException
      Maps name to value, clobbering any existing name/value mapping with the same name.
      Parameters:
      name - The name of the value to insert.
      value - The value to insert.
      Returns:
      this object.
      Throws:
      JSONException - Should not be possible.

    • put

      public JSONObject put(String name, double value) throws JSONException
      Maps name to value, clobbering any existing name/value mapping with the same name.
      Parameters:
      name - The name for the new value.
      value - a finite value. May not be NaNs or infinities.
      Returns:
      this object.
      Throws:
      JSONException - if value is NaN or infinite.

    • put

      public JSONObject put(String name, int value) throws JSONException
      Maps name to value, clobbering any existing name/value mapping with the same name.
      Parameters:
      name - The name for the new value.
      value - The new value.
      Returns:
      this object.
      Throws:
      JSONException - Should not be possible.

    • put

      public JSONObject put(String name, long value) throws JSONException
      Maps name to value, clobbering any existing name/value mapping with the same name.
      Parameters:
      name - The name of the new value.
      value - The new value to insert.
      Returns:
      this object.
      Throws:
      JSONException - Should not be possible.

    • put

      public JSONObject put(String name, 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:
      name - The name of the new value.
      value - a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL, or null. May not be NaNs or infinities. If value is Map or Collection the value is wrapped using corresponding JSONObject(map) or JSONArray(collection) object. This behavior is considered unsafe and is added for compatibility with original 'org.json' package only.
      Returns:
      this object.
      Throws:
      JSONException - if the value is an invalid double (infinite or NaN).

    • putOpt

      public JSONObject putOpt(String name, Object value) throws JSONException
      Equivalent to put(name, value) when both parameters are non-null; does nothing otherwise.
      Parameters:
      name - The name of the value to insert.
      value - The value to insert.
      Returns:
      this object.
      Throws:
      JSONException - if the value is an invalid double (infinite or NaN).

    • accumulate

      public JSONObject accumulate(String name, 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:
      name - The name of the field to change.
      value - a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL or null. May not be NaNs or infinities.
      Returns:
      this object after mutation.
      Throws:
      JSONException - If the object being added is an invalid number.

    • append

      public JSONObject append(String name, Object value) throws JSONException
      Appends values to the array mapped to name. A new JSONArray mapping for name will be inserted if no mapping exists. If the existing mapping for name is not a JSONArray, a JSONException will be thrown.
      Parameters:
      name - The name of the array to which the value should be appended.
      value - The value to append.
      Returns:
      this object.
      Throws:
      JSONException - if name is null or if the mapping for name is non-null and is not a JSONArray.

    • checkName

      String checkName(String name) throws JSONException
      Throws:
      JSONException

    • remove

      public Object remove(String name)
      Removes the named mapping if it exists; does nothing otherwise.
      Parameters:
      name - The name of the mapping to remove.
      Returns:
      the value previously mapped by name, or null if there was no such mapping.

    • isNull

      public boolean isNull(String name)
      Returns true if this object has no mapping for name or if it has a mapping whose value is NULL.
      Parameters:
      name - The name of the value to check on.
      Returns:
      true if the field doesn't exist or is null.

    • has

      public boolean has(String name)
      Returns true if this object has a mapping for name. The mapping may be NULL.
      Parameters:
      name - The name of the value to check on.
      Returns:
      true if this object has a field named name

    • get

      public Object get(String name) throws JSONException
      Returns the value mapped by name, or throws if no such mapping exists.
      Parameters:
      name - The name of the value to get.
      Returns:
      The value.
      Throws:
      JSONException - if no such mapping exists.

    • opt

      public Object opt(String name)
      Returns the value mapped by name, or null if no such mapping exists.
      Parameters:
      name - The name of the value to get.
      Returns:
      The value.

    • getBoolean

      public boolean getBoolean(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.
      Parameters:
      name - The name of the field we want.
      Returns:
      The selected value if it exists.
      Throws:
      JSONException - if the mapping doesn't exist or cannot be coerced to a boolean.

    • optBoolean

      public boolean optBoolean(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.
      Parameters:
      name - The name of the field we want.
      Returns:
      The selected value if it exists.

    • optBoolean

      public boolean optBoolean(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.
      Parameters:
      name - The name of the field we want.
      fallback - The value to return if the field isn't there.
      Returns:
      The selected value or the fallback.

    • getDouble

      public double getDouble(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.
      Parameters:
      name - The name of the field we want.
      Returns:
      The selected value if it exists.
      Throws:
      JSONException - if the mapping doesn't exist or cannot be coerced to a double.

    • optDouble

      public double optDouble(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.
      Parameters:
      name - The name of the field we want.
      Returns:
      The selected value if it exists.

    • optDouble

      public double optDouble(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.
      Parameters:
      name - The name of the field we want.
      fallback - The value to return if the field isn't there.
      Returns:
      The selected value or the fallback.

    • getInt

      public int getInt(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.
      Parameters:
      name - The name of the field we want.
      Returns:
      The selected value if it exists.
      Throws:
      JSONException - if the mapping doesn't exist or cannot be coerced to an int.

    • optInt

      public int optInt(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.
      Parameters:
      name - The name of the field we want.
      Returns:
      The selected value if it exists.

    • optInt

      public int optInt(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.
      Parameters:
      name - The name of the field we want.
      fallback - The value to return if the field isn't there.
      Returns:
      The selected value or the fallback.

    • getLong

      public long getLong(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 without loss.
      Parameters:
      name - The name of the field that we want.
      Returns:
      The value of the field.
      Throws:
      JSONException - if the mapping doesn't exist or cannot be coerced to a long.

    • optLong

      public long optLong(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.
      Parameters:
      name - The name of the field we want.
      Returns:
      The selected value.

    • optLong

      public long optLong(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.
      Parameters:
      name - The name of the field we want.
      fallback - The value to return if the field isn't there.
      Returns:
      The selected value or the fallback.

    • getString

      public String getString(String name) throws JSONException
      Returns the value mapped by name if it exists, coercing it if necessary, or throws if no such mapping exists.
      Parameters:
      name - The name of the field we want.
      Returns:
      The value of the field.
      Throws:
      JSONException - if no such mapping exists.

    • optString

      public String optString(String name)
      Returns the value mapped by name if it exists, coercing it if necessary, or the empty string if no such mapping exists.
      Parameters:
      name - The name of the field we want.
      Returns:
      The value of the field.

    • optString

      public String optString(String name, String fallback)
      Returns the value mapped by name if it exists, coercing it if necessary, or fallback if no such mapping exists.
      Parameters:
      name - The name of the field that we want.
      fallback - The value to return if the field doesn't exist.
      Returns:
      The value of the field or fallback.

    • getJSONArray

      public JSONArray getJSONArray(String name) throws JSONException
      Returns the value mapped by name if it exists and is a JSONArray, or throws otherwise.
      Parameters:
      name - The field we want to get.
      Returns:
      The value of the field (if it is a JSONArray.
      Throws:
      JSONException - if the mapping doesn't exist or is not a JSONArray.

    • optJSONArray

      public JSONArray optJSONArray(String name)
      Returns the value mapped by name if it exists and is a JSONArray, or null otherwise.
      Parameters:
      name - The name of the field we want.
      Returns:
      The value of the specified field (assuming it is a JSNOArray

    • getJSONObject

      public JSONObject getJSONObject(String name) throws JSONException
      Returns the value mapped by name if it exists and is a JSONObject, or throws otherwise.
      Parameters:
      name - The name of the field that we want.
      Returns:
      a specified field value (if it is a JSONObject)
      Throws:
      JSONException - if the mapping doesn't exist or is not a JSONObject.

    • optJSONObject

      public JSONObject optJSONObject(String name)
      Returns the value mapped by name if it exists and is a JSONObject, or null otherwise.
      Parameters:
      name - The name of the value we want.
      Returns:
      The specified value.

    • 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.
      Parameters:
      names - The names of the fields that we want the values for.
      Returns:
      The selected values.
      Throws:
      JSONException - On internal errors. Shouldn't happen.

    • keys

      public Iterator<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.
      Returns:
      an iterator over the keys.

    • keySet

      public Set<String> keySet()
      Returns the set of String names in this object. The returned set is a view of the keys in this object. Set.remove(Object) will remove the corresponding mapping from this object and set iterator behaviour is undefined if this object is modified after it is returned. See keys().
      Returns:
      The names in this object.

    • names

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

    • toString

      public String toString()
      Encodes this object as a compact JSON string, such as: 
      {"query":"Pizza","locations":[94043,90210]}
      Note 1: this method will not output any fields with 'null' value. Override JSONStringer.entry(java.util.Map.Entry<java.lang.String, java.lang.Object>) method to have nulls printed. Note 2: this method will suppress any internal exceptions. Use toString(JSONStringer) method directly to handle exceptions manually.
      Overrides:
      toString in class Object

    • toString

      public 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.
      Returns:
      The string containing the pretty form of this.
      Throws:
      JSONException - On internal errors. Shouldn't happen.

    • toString

      public String toString(JSONStringer stringer) throws JSONException
      Encodes this object using JSONStringer provided
      Parameters:
      stringer - - JSONStringer to be used for serialization
      Returns:
      The string representation of this.
      Throws:
      JSONException - On internal errors. Shouldn't happen.

    • encode

      protected void encode(JSONStringer stringer) throws JSONException
      Encodes this object using JSONStringer provided
      Parameters:
      stringer - - JSONStringer to be used for serialization
      Throws:
      JSONException - On internal errors. Shouldn't happen.

    • numberToString

      public static String numberToString(Number number) throws JSONException
      Encodes the number as a JSON string.
      Parameters:
      number - a finite value. May not be NaNs or infinities.
      Returns:
      The encoded number in string form.
      Throws:
      JSONException - On internal errors. Shouldn't happen.

    • quote

      public static String quote(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.
      Returns:
      the quoted string.

    • wrap

      public static Object wrap(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. If the object is from a java package, returns the result of toString. If the object is some other kind of object then it is assumed to be a bean and is converted to a JSONObject. If wrapping fails, returns null.

      Parameters:
      o - The object to wrap.
      Returns:
      The wrapped (if necessary) form of the object {$code o}