org.apache.tapestry5.json

Class JSONArray

java.lang.Object

org.apache.tapestry5.json.JSONCollection

org.apache.tapestry5.json.JSONArray

All Implemented Interfaces:

Serializable, Iterable<Object>

public final class JSONArray
extends JSONCollection
implements Iterable<Object>

A JSONArray is an ordered sequence of values. Its external text form is a string wrapped in square brackets with commas separating the values. The internal form is an object having get and opt methods for accessing the values by index, and put methods for adding or replacing values. The values can be any of these types: Boolean, JSONArray, JSONObject, Number, String, or the JSONObject.NULL object. The constructor can convert a JSON text into a Java object. The toString method converts to JSON text. A get method returns a value if one can be found, and throws an exception if one cannot be found. An opt method returns a default value instead of throwing an exception, and so is useful for obtaining optional values. The generic get() and opt() methods return an object which you can cast or query for type. There are also typed get and opt methods that do type checking and type coersion for you. The texts produced by the toString methods strictly conform to JSON syntax rules. The constructors are more forgiving in the texts they will accept:

• An extra , (comma) may appear just before the closing bracket.
• The null value will be inserted when there is , (comma) elision.
• 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.
• Values can be separated 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.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
JSONArray() Construct an empty JSONArray.
JSONArray(Object... values)
JSONArray(String text)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object obj)
static JSONArray	from(Iterable<?> iterable) Create a new array, and adds all values fro the iterable to the array (using putAll(Iterable).
Object	get(int index) Get the object value associated with an index.
boolean	getBoolean(int index) Get the boolean value associated with an index.
double	getDouble(int index) Get the double value associated with an index.
int	getInt(int index) Get the int value associated with an index.
JSONArray	getJSONArray(int index) Get the JSONArray associated with an index.
JSONObject	getJSONObject(int index) Get the JSONObject associated with an index.
long	getLong(int index) Get the long value associated with an index.
String	getString(int index) Get the string associated with an index.
boolean	isNull(int index) Determine if the value is null.
Iterator<Object>	iterator()
int	length() Get the number of elements in the JSONArray, included nulls.
JSONArray	put(int index, Object value) Put or replace an object value in the JSONArray.
JSONArray	put(Object value) Append an object value.
JSONArray	putAll(Iterable<?> collection) Puts all objects from the collection into this JSONArray, using put(Object).
Object	remove(int index) Remove the object associated with the index.
List<Object>	toList() Returns an unmodifiable list of the contents of the array.

Methods inherited from class org.apache.tapestry5.json.JSONCollection

prettyPrint, print, print, toCompactString, toString, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

JSONArray

public JSONArray()

Construct an empty JSONArray.

JSONArray

public JSONArray(String text)

JSONArray

public JSONArray(Object... values)

Method Detail

from

public static JSONArray from(Iterable<?> iterable)

Create a new array, and adds all values fro the iterable to the array (using putAll(Iterable). This is implemented as a static method so as not to break the semantics of the existing JSONArray(Object...) constructor. Adding a constructor of type Iterable would change the meaning of new JSONArray(new JSONArray()).

Parameters:

iterable - collection ot value to include, or null

Since:

5.4

iterator

public Iterator<Object> iterator()

Specified by:

iterator in interface Iterable<Object>

get

public Object get(int index)

Get the object value associated with an index.

Parameters:

index - The index must be between 0 and length() - 1.

Returns:

An object value.

Throws:

RuntimeException - If there is no value for the index.

remove

public Object remove(int index)

Remove the object associated with the index.

Parameters:

index - The index must be between 0 and length() - 1.

Returns:

An object removed.

Throws:

RuntimeException - If there is no value for the index.

getBoolean

public boolean getBoolean(int index)

Get the boolean value associated with an index. The string values "true" and "false" are converted to boolean.

Parameters:

index - The index must be between 0 and length() - 1.

Returns:

The truth.

Throws:

RuntimeException - If there is no value for the index or if the value is not convertable to boolean.

getDouble

public double getDouble(int index)

Get the double value associated with an index.

Parameters:

index - The index must be between 0 and length() - 1.

Returns:

The value.

Throws:

IllegalArgumentException - If the key is not found or if the value cannot be converted to a number.

getInt

public int getInt(int index)

Get the int value associated with an index.

Parameters:

index - The index must be between 0 and length() - 1.

Returns:

The value.

Throws:

IllegalArgumentException - If the key is not found or if the value cannot be converted to a number. if the value cannot be converted to a number.

getJSONArray

public JSONArray getJSONArray(int index)

Get the JSONArray associated with an index.

Parameters:

index - The index must be between 0 and length() - 1.

Returns:

A JSONArray value.

Throws:

RuntimeException - If there is no value for the index. or if the value is not a JSONArray

getJSONObject

public JSONObject getJSONObject(int index)

Get the JSONObject associated with an index.

Parameters:

index - subscript

Returns:

A JSONObject value.

Throws:

RuntimeException - If there is no value for the index or if the value is not a JSONObject

getLong

public long getLong(int index)

Get the long value associated with an index.

Parameters:

index - The index must be between 0 and length() - 1.

Returns:

The value.

Throws:

IllegalArgumentException - If the key is not found or if the value cannot be converted to a number.

getString

public String getString(int index)

Get the string associated with an index.

Parameters:

index - The index must be between 0 and length() - 1.

Returns:

A string value.

Throws:

RuntimeException - If there is no value for the index.

isNull

public boolean isNull(int index)

Determine if the value is null.

Parameters:

index - The index must be between 0 and length() - 1.

Returns:

true if the value at the index is null, or if there is no value.

length

public int length()

Get the number of elements in the JSONArray, included nulls.

Returns:

The length (or size).

put

public JSONArray put(Object value)

Append an object value. This increases the array's length by one.

Parameters:

value - An object value. The value should be a Boolean, Double, Integer, JSONArray, JSONObject, JSONLiteral, Long, or String, or the JSONObject.NULL singleton.

Returns:

this array

put

public JSONArray put(int index,
            Object value)

Put or replace an object value in the JSONArray. If the index is greater than the length of the JSONArray, then null elements will be added as necessary to pad it out.

Parameters:

index - The subscript.

value - The value to put into the array. The value should be a Boolean, Double, Integer, JSONArray, JSONObject, JSONString, Long, or String, or the JSONObject.NULL singeton.

Returns:

this array

Throws:

RuntimeException - If the index is negative or if the the value is an invalid number.

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

putAll

public JSONArray putAll(Iterable<?> collection)

Puts all objects from the collection into this JSONArray, using put(Object).

Parameters:

collection - List, array, JSONArray, or other iterable object, or null

Returns:

this JSONArray

Since:

5.4

toList

public List<Object> toList()

Returns an unmodifiable list of the contents of the array. This is a wrapper around the list's internal storage and is live (changes to the JSONArray affect the returned List).

Returns:

unmodifiable list of array contents

Since:

5.4