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
* coercion for you. The opt methods differ from the get methods in that they do
* not throw. Instead, they return a specified value, such as null.
*
* The put methods add or replace values in 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:
*
, (comma) may appear just
* before the closing brace.' (single
* quote).{ } [ ] / \ : , # and if they do not look like numbers and if
* they are not the reserved words true, false, or
* null.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();
/**
* Construct an empty JSONObject.
*/
public JSONObject() {
this.map = new HashMap();
}
/**
* 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.
*
* @param jo
* A JSONObject.
* @param names
* An array of strings.
* @throws JSONException
* @exception JSONException
* If a value is a non-finite number or if a name is
* duplicated.
*/
public JSONObject(JSONObject jo, String[] names) {
this();
for (int i = 0; i < names.length; i += 1) {
try {
this.putOnce(names[i], jo.opt(names[i]));
} catch (Exception ignore) {
}
}
}
/**
* Construct a JSONObject from a JSONTokener.
*
* @param x
* A JSONTokener object containing the source string.
* @throws JSONException
* If there is a syntax error in the source string or a
* duplicated key.
*/
public JSONObject(JSONTokener x) throws JSONException {
this();
parse(x);
setSearchByPathChars('.', '[', ']');
}
public void parse(String jsonString) {
parse(new JSONTokener(jsonString));
}
public void parse(JSONTokener x) {
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 ':'.
c = x.nextClean();
if (c != ':') {
throw x.syntaxError("Expected a ':' after a key");
}
this.putOnce(key, x.nextValue());
// Pairs are separated by ','.
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.
*
* @param map
* A map object that can be used to initialize the contents of
* the JSONObject.
* @throws JSONException
*/
public JSONObject(Map map) {
this.map = new HashMap();
if (map != null) {
Iterator i = map.entrySet().iterator();
while (i.hasNext()) {
Map.Entry e = (Map.Entry) i.next();
Object value = e.getValue();
if (value != null) {
this.map.put(e.getKey(), wrap(value));
}
}
}
}
/**
* Construct a JSONObject from an Object using bean getters. It reflects on
* all of the public methods of the object. For each of the methods with no
* parameters and a name starting with "get" or
* "is" followed by an uppercase letter, the method is invoked,
* and a key and the value returned from the getter method are put into the
* new JSONObject.
*
* The key is formed by removing the "get" or "is"
* prefix. If the second remaining character is not upper case, then the
* first character is converted to lower case.
*
* For example, if an object has a method named "getName", and
* if the result of calling object.getName() is
* "Larry Fine", then the JSONObject will contain
* "name": "Larry Fine".
*
* @param bean
* An object that has getter methods that should be used to make
* a JSONObject.
*/
public JSONObject(Object bean) {
this();
this.populateMap(bean);
}
/**
* 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.
*
* @param object
* An object that has fields that should be used to make a
* JSONObject.
* @param names
* An array of strings, the names of the fields to be obtained
* from the object.
*/
public JSONObject(Object object, String names[]) {
this();
Class c = object.getClass();
for (int i = 0; i < names.length; i += 1) {
String name = names[i];
try {
this.putOpt(name, c.getField(name).get(object));
} catch (Exception ignore) {
}
}
}
/**
* Construct a JSONObject from a source JSON text string. This is the most
* commonly used JSONObject constructor.
*
* @param source
* A string beginning with { (left
* brace) and ending with }
* (right brace).
* @exception JSONException
* If there is a syntax error in the source string or a
* duplicated key.
*/
public JSONObject(String source) throws JSONException {
this(new JSONTokener(source));
}
/**
* Construct a JSONObject from a ResourceBundle.
*
* @param baseName
* The ResourceBundle base name.
* @param locale
* The Locale to load the ResourceBundle for.
* @throws JSONException
* If any JSONExceptions are detected.
*/
public JSONObject(String baseName, Locale locale) throws JSONException {
this();
ResourceBundle bundle = ResourceBundle.getBundle(baseName, locale,
Thread.currentThread().getContextClassLoader());
// Iterate through the keys in the bundle.
Enumeration keys = bundle.getKeys();
while (keys.hasMoreElements()) {
Object key = keys.nextElement();
if (key instanceof String) {
// Go through the path, ensuring that there
// is a nested
// JSONObject for each
// segment except the last. Add the value
// using the last
// segment's name into
// the deepest nested JSONObject.
String[] path = ((String) key).split("\\.");
int last = path.length - 1;
JSONObject target = this;
for (int i = 0; i < last; i += 1) {
String segment = path[i];
JSONObject nextTarget = target.optJSONObject(segment);
if (nextTarget == null) {
nextTarget = new JSONObject();
target.put(segment, nextTarget);
}
target = nextTarget;
}
target.put(path[last], bundle.getString((String) key));
}
}
}
/**
* 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.
*
* If only one value is accumulated that is not a JSONArray, then the result
* will be the same as using put. But if multiple values are accumulated,
* then the result will be like append.
*
* @param key
* A key string.
* @param value
* An object to be accumulated under the key.
* @return this.
* @throws JSONException
* If the value is an invalid number or if the key is null.
*/
public JSONObject accumulate(String key, Object value) throws JSONException {
testValidity(value);
Object object = this.opt(key);
if (object == null) {
this.put(key,
value instanceof JSONArray ? new JSONArray().put(value)
: value);
} else if (object instanceof JSONArray) {
((JSONArray) object).put(value);
} else {
this.put(key, new JSONArray().put(object).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.
*
* @param key
* A key string.
* @param value
* An object to be accumulated under the key.
* @return 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 key, Object value) throws JSONException {
testValidity(value);
Object object = this.opt(key);
if (object == null) {
this.put(key, new JSONArray().put(value));
} else if (object instanceof JSONArray) {
this.put(key, ((JSONArray) object).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.
*
* @param d
* A double.
* @return 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 string = Double.toString(d);
if (string.indexOf('.') > 0 && string.indexOf('e') < 0
&& string.indexOf('E') < 0) {
while (string.endsWith("0")) {
string = string.substring(0, string.length() - 1);
}
if (string.endsWith(".")) {
string = string.substring(0, string.length() - 1);
}
}
return string;
}
/**
* Get the value object associated with a key.
*
* @param key
* A key string or a search path. * When a key is used the associated object is directly returned. *
* When a search path is used, determined by dots or brackets in * the key, a more thorough and traversal search is performed. *
* Typical is that the first object that match is the one that is * returned, regardless of if there are more available that also * match. *
* It is possible to search among objects by dot notation like
* this: jsonObject.get("parent.child.child");
*
* In case of arrays this syntax can be used:
* jsonObject.get("parentArray[elementName==value].childArray[child.element!=value].child");
*
* Consider that this JSON has been used: *
* *
* {
* parent: {
* child: {
* child: {
* element: "value"
* }
* }
* },
* parentArray: [
* {
* elementName: "value",
* childArray: [
* {
* child: {
* element: "value"
* }
* }
* ]
* }
* ]
* }
*
*
* These test operands can be used:
* == : Equality test
* != : Not equal test
* < : Less than test
* > : Greater than test
* <= : Less than or equal test
* >= : Greater than or equal test
* *= : Contains text test
* !* : Not contains text test
* ^= : Starts with text test
* !^ : Not starts with text test
* $= : Ends with text test
* !$ : Not ends with text test
* * Typical is that the first object that match is the one that is returned, * regardless of if there are more available that also match. *
* It is possible to search by dot notation like this:
* jsonObject.getString("first.second.third.string");
*
* In case of arrays this syntax can be used:
* jsonObject.getString("first[element==value].second[element.element!=value].string");
*
* These test operands can be used: *
* Warning: This method assumes that the data structure is acyclical.
*
* @return a printable, displayable, portable, transmittable representation
* of the object, beginning with { (left
* brace) and ending with } (right
* brace).
*/
public String toString() {
try {
return this.toString(0);
} catch (Exception e) {
return null;
}
}
/**
* Make a prettyprinted JSON text of this JSONObject.
*
* Warning: This method assumes that the data structure is acyclical.
*
* @param indentFactor
* The number of spaces to add to each level of indentation.
* @return 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 indentFactor) throws JSONException {
StringWriter w = new StringWriter();
synchronized (w.getBuffer()) {
return this.write(w, indentFactor, 0).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 other means. If the value
* is an array or Collection, then a JSONArray will be made from it and its
* toJSONString method will be called. If the value is a MAP, then a
* JSONObject will be made from it and its toJSONString method will be
* called. Otherwise, the value's toString method will be called, and the
* result will be quoted.
*
*
* Warning: This method assumes that the data structure is acyclical.
*
* @param value
* The value to be serialized.
* @return 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.
*/
public static String valueToString(Object value) throws JSONException {
if (value == null || value.equals(null)) {
return "null";
}
if (value instanceof JSONString) {
Object object;
try {
object = ((JSONString) value).toJSONString();
} catch (Exception e) {
throw new JSONException(e);
}
if (object instanceof String) {
return (String) object;
}
throw new JSONException("Bad value from toJSONString: " + object);
}
if (value instanceof Number) {
return numberToString((Number) value);
}
if (value instanceof Boolean || value instanceof JSONObject
|| value instanceof JSONArray) {
return value.toString();
}
if (value instanceof Map) {
return new JSONObject((Map) value).toString();
}
if (value instanceof Collection) {
return new JSONArray((Collection) value).toString();
}
if (value.getClass().isArray()) {
return new JSONArray(value).toString();
}
return quote(value.toString());
}
/**
* Wrap an object, if necessary. If the object is null, return the NULL
* object. If it is an array or collection, wrap it in a JSONArray. If it is
* a map, wrap it in a JSONObject. If it is a standard property (Double,
* String, et al) then it is already wrapped. Otherwise, if it comes from
* one of the java packages, turn it into a string. And if it doesn't, try
* to wrap it in a JSONObject. If the wrapping fails, then null is returned.
*
* @param object
* The object to wrap
* @return The wrapped value
*/
public static Object wrap(Object object) {
try {
if (object == null) {
return NULL;
}
if (object instanceof JSONObject || object instanceof JSONArray
|| NULL.equals(object) || object instanceof JSONString
|| object instanceof Byte || object instanceof Character
|| object instanceof Short || object instanceof Integer
|| object instanceof Long || object instanceof Boolean
|| object instanceof Float || object instanceof Double
|| object instanceof String) {
return object;
}
if (object instanceof Collection) {
return new JSONArray((Collection) object);
}
if (object.getClass().isArray()) {
return new JSONArray(object);
}
if (object instanceof Map) {
return new JSONObject((Map) object);
}
Package objectPackage = object.getClass().getPackage();
String objectPackageName = objectPackage != null ? objectPackage
.getName() : "";
if (objectPackageName.startsWith("java.")
|| objectPackageName.startsWith("javax.")
|| object.getClass().getClassLoader() == null) {
return object.toString();
}
return new JSONObject(object);
} catch (Exception exception) {
return null;
}
}
/**
* 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. * * @return The writer. * @throws JSONException */ public Writer write(Writer writer) throws JSONException { return this.write(writer, 0, 0); } static final Writer writeValue(Writer writer, Object value, int indentFactor, int indent) throws JSONException, IOException { if (value == null || value.equals(null)) { writer.write("null"); } else if (value instanceof JSONObject) { ((JSONObject) value).write(writer, indentFactor, indent); } else if (value instanceof JSONArray) { ((JSONArray) value).write(writer, indentFactor, indent); } else if (value instanceof Map) { new JSONObject((Map) value).write(writer, indentFactor, indent); } else if (value instanceof Collection) { new JSONArray((Collection) value).write(writer, indentFactor, indent); } else if (value.getClass().isArray()) { new JSONArray(value).write(writer, indentFactor, indent); } else if (value instanceof Number) { writer.write(numberToString((Number) value)); } else if (value instanceof Boolean) { writer.write(value.toString()); } else if (value instanceof JSONString) { Object o; try { o = ((JSONString) value).toJSONString(); } catch (Exception e) { throw new JSONException(e); } writer.write(o != null ? o.toString() : quote(value.toString())); } else { quote(value.toString(), writer); } return writer; } static final void indent(Writer writer, int indent) throws IOException { for (int i = 0; i < indent; i += 1) { writer.write(' '); } } /** * 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. * * @return The writer. * @throws JSONException */ Writer write(Writer writer, int indentFactor, int indent) throws JSONException { try { boolean commanate = false; final int length = this.length(); Iterator keys = this.keys(); writer.write('{'); if (length == 1) { Object key = keys.next(); writer.write(quote(key.toString())); writer.write(':'); if (indentFactor > 0) { writer.write(' '); } writeValue(writer, this.map.get(key), indentFactor, indent); } else if (length != 0) { final int newindent = indent + indentFactor; while (keys.hasNext()) { Object key = keys.next(); if (commanate) { writer.write(','); } if (indentFactor > 0) { writer.write('\n'); } indent(writer, newindent); writer.write(quote(key.toString())); writer.write(':'); if (indentFactor > 0) { writer.write(' '); } writeValue(writer, this.map.get(key), indentFactor, newindent); commanate = true; } if (indentFactor > 0) { writer.write('\n'); } indent(writer, indent); } writer.write('}'); return writer; } catch (IOException exception) { throw new JSONException(exception); } } }