Reference:Java.nio.charset.Charset

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java.nio.charset
public abstract class java.nio.charset.Charset

java.lang.Object
	java.nio.charset.Charset	Comparable

A charset defines a mapping between a Unicode character sequence and a byte sequence. It facilitate the encoding from a Unicode character sequence into a byte sequence, and the decoding from a byte sequence into a Unicode character sequence.

A charset has a canonical name, which are usually in uppercase. Typically it also has one or more aliases. The name string can only consist of the following characters: '0' - '9', 'A' - 'Z', 'a' - 'z', '.', ':'. '-' and '_'. The first character of the name must be a digit or a letter.

The following charsets should be supported by any java platforms: US-ASCII, ISO-8859-1, UTF-8, UTF-16BE, UTF-16LE, UTF-16.

Additional charsets can be made available by configuring one or more charset providers through provider configuration files. Such files are always named as "java.nio.charset.spi.CharsetProvider" and located in the "META-INF/services" sub folder of one or more classpaths. The files should be encoded in "UTF-8". Each line of their content specifies the class name of a charset provider which extends java.nio.spi.CharsetProvider. A line should ends with '\r', '\n' or '\r\n'. Leading and trailing whitespaces are trimmed. Blank lines, and lines (after trimmed) starting with "#" which are regarded as comments, are both ignored. Duplicates of already appeared names are also ignored. Both the configuration files and the provider classes will be loaded using the thread context class loader.

This class is thread-safe.

See Also

• CharsetProvider

Contents 1 Summary 1.1 Protected Constructors 1.2 Public Methods 1.2.1 Methods inherited from class java.lang.Object 1.2.2 Methods inherited from interface java.lang.Comparable 2 Details 2.1 Protected Constructors 2.1.1 protected Charset(String canonicalName, String[ ] aliases) 2.2 Public Methods 2.2.1 public final Set aliases() 2.2.2 public static SortedMap availableCharsets() 2.2.3 public boolean canEncode() 2.2.4 public final int compareTo(Charset charset) 2.2.5 public abstract boolean contains(Charset charset) 2.2.6 public final CharBuffer decode(ByteBuffer buffer) 2.2.7 public static Charset defaultCharset() 2.2.8 public String displayName() 2.2.9 public String displayName(Locale l) 2.2.10 public final synchronized ByteBuffer encode(CharBuffer buffer) 2.2.11 public final ByteBuffer encode(String s) 2.2.12 public final boolean equals(Object obj) 2.2.13 public static Charset forName(String charsetName) 2.2.14 public final int hashCode() 2.2.15 public final boolean isRegistered() 2.2.16 public static boolean isSupported(String charsetName) 2.2.17 public final String name() 2.2.18 public abstract CharsetDecoder newDecoder() 2.2.19 public abstract CharsetEncoder newEncoder() 2.2.20 public final String toString() 3 References

[edit] Summary

[edit] Protected Constructors

					Charset (String canonicalName, String[ ] aliases)
					Constructs a Charset object.

[edit] Public Methods

		final		Set	aliases ()
					Gets the set of this charset's aliases.
			static	SortedMap	availableCharsets ()
					Gets a map of all available charsets supported by the runtime.
				boolean	canEncode ()
					Answers true if this charset supports encoding, otherwise false.
		final		int	compareTo (Charset charset)
					Compares this charset with the given charset.
abstract				boolean	contains (Charset charset)
					Determines whether this charset is a super set of the given charset.
		final		CharBuffer	decode (ByteBuffer buffer)
					Decodes the content of the give byte buffer and outputs to a character buffer that is to be returned.
			static	Charset	defaultCharset ()
					Gets the system default charset from jvm.
				String	displayName ()
					Gets the name of this charset for the default locale.
				String	displayName (Locale l)
					Gets the name of this charset for the specified locale.
	synchronized	final		ByteBuffer	encode (CharBuffer buffer)
					Encodes the content of the give character buffer and outputs to a byte buffer that is to be returned.
		final		ByteBuffer	encode (String s)
					Encodes a string and outputs to a byte buffer that is to be returned.
		final		boolean	equals (Object obj)
					Determines whether this charset equals to the given object.
			static	Charset	forName (String charsetName)
					Gets a Charset instance for the specified charset name.
		final		int	hashCode ()
					Gets the hash code of this charset.
		final		boolean	isRegistered ()
					Answers whether this charset is known to be registered in the IANA Charset Registry.
			static	boolean	isSupported (String charsetName)
					Determines whether the specified charset is supported by this runtime.
		final		String	name ()
					Gets the canonical name of this charset.
abstract				CharsetDecoder	newDecoder ()
					Gets a new instance of decoder for this charset.
abstract				CharsetEncoder	newEncoder ()
					Gets a new instance of encoder for this charset.
		final		String	toString ()
					Gets a string representation of this charset.

[edit] Methods inherited from class java.lang.Object

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

[edit] Methods inherited from interface java.lang.Comparable

compareTo

[edit] Details

[edit] Protected Constructors

[edit] protected Charset(String canonicalName, String[ ] aliases)

Constructs a Charset object. Duplicated aliases are ignored.

Parameters

canonicalName	the canonical name of the charset
aliases	an array containing all aliases of the charset

Throws

IllegalCharsetNameException	on an illegal value being supplied for either canonicalName or for any element of aliases.

[edit] Public Methods

[edit] public final Set aliases()

Gets the set of this charset's aliases.

Returns

• an unmodifiable set of this charset's aliases

[edit] public static SortedMap availableCharsets()

Gets a map of all available charsets supported by the runtime.

The returned map contains mappings from canonical names to corresponding instances of Charset. The canonical names can be considered as case-insensitive.

Returns

• an unmodifiable map of all available charsets supported by the runtime

[edit] public boolean canEncode()

Answers true if this charset supports encoding, otherwise false.

Returns

• true

[edit] public final int compareTo(Charset charset)

Compares this charset with the given charset.

Parameters

charset	the given object to be compared with

Returns

• a negative integer if less than the given object, a positive integer if larger than it, or 0 if equal to it

[edit] public abstract boolean contains(Charset charset)

Determines whether this charset is a super set of the given charset.

Parameters

charset	a given charset

Returns

• true if this charset is a super set of the given charset, otherwise false

[edit] public final CharBuffer decode(ByteBuffer buffer)

Decodes the content of the give byte buffer and outputs to a character buffer that is to be returned.

The default action in case of decoding errors is CodingErrorAction.REPLACE.

Parameters

buffer	the byte buffer containing the content to be decoded

Returns

• a character buffer containing the output of the decoding

[edit] public static Charset defaultCharset()

Gets the system default charset from jvm.

Returns

• the default charset

[edit] public String displayName()

Gets the name of this charset for the default locale.

Returns

• the name of this charset for the default locale

[edit] public String displayName(Locale l)

Gets the name of this charset for the specified locale.

Parameters

l	a certain locale

Returns

• the name of this charset for the specified locale

[edit] public final synchronized ByteBuffer encode(CharBuffer buffer)

Encodes the content of the give character buffer and outputs to a byte buffer that is to be returned.

The default action in case of encoding errors is CodingErrorAction.REPLACE.

Parameters

buffer	the character buffer containing the content to be encoded

Returns

• the result of the encoding

[edit] public final ByteBuffer encode(String s)

Encodes a string and outputs to a byte buffer that is to be returned.

The default action in case of encoding errors is CodingErrorAction.REPLACE.

Parameters

s	the string to be encoded

Returns

• the result of the encoding

[edit] public final boolean equals(Object obj)

Determines whether this charset equals to the given object. They are considered to be equal if they have the same canonical name.

Parameters

obj	the given object to be compared with

Returns

• true if they have the same canonical name, otherwise false

[edit] public static Charset forName(String charsetName)

Gets a Charset instance for the specified charset name.

Parameters

charsetName	the name of the charset

Returns

• a Charset instance for the specified charset name

Throws

IllegalCharsetNameException	If the specified charset name is illegal.
UnsupportedCharsetException	If the desired charset is not supported by this runtime.

[edit] public final int hashCode()

Gets the hash code of this charset.

Returns

• the hash code of this charset

[edit] public final boolean isRegistered()

Answers whether this charset is known to be registered in the IANA Charset Registry.

Returns

• true if the charset is known to be registered, otherwise returns false.

[edit] public static boolean isSupported(String charsetName)

Determines whether the specified charset is supported by this runtime.

Parameters

charsetName	the name of the charset

Returns

• true if the specified charset is supported, otherwise false

Throws

IllegalCharsetNameException	If the specified charset name is illegal.

[edit] public final String name()

Gets the canonical name of this charset.

Returns

• this charset's name in canonical form.

[edit] public abstract CharsetDecoder newDecoder()

Gets a new instance of decoder for this charset.

Returns

• a new instance of decoder for this charset

[edit] public abstract CharsetEncoder newEncoder()

Gets a new instance of encoder for this charset.

Returns

• a new instance of encoder for this charset

[edit] public final String toString()

Gets a string representation of this charset. Usually this contains the canonical name of the charset.

Returns

• a string representation of this charset

[edit] References

• Original documentation page for Android SDK build m5-rc15e - 14 apr 2008 17:27