CharBuffer

CharBuffer

java.nio

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Java 1.4

comparable appendable readable

CharBuffer holds a sequence of Unicode character values for use in an I/O operation. Most of the methods of this class are directly analogous to methods defined by ByteBuffer except that they use char and char[ ] argument and return values instead of byte and byte[ ] values. See ByteBuffer for details.

In addition to the ByteBuffer analogs, this class also implements the java.lang.CharSequence interface so that it can be used with java.util.regex regular expression operations or anywhere else a CharSequence is expected. In Java 5.0, CharBuffer adds the append( ) and read( ) methods of the java.lang.Appendable and java.lang.Readable interfaces, making CharBuffer objects suitable for use with the Formatter and Scanner classes of java.util .

Note that CharBuffer is an abstract class and does not defined a constructor. There are three ways to obtain a CharBuffer :

• By calling the static allocate( ) method. Note that there is no allocateDirect( ) method as there is for ByteBuffer .

• By calling one of the static wrap( ) methods to create a CharBuffer that uses the specified char array or CharSequence for its content. Note that wrapping a CharSequence results in a read-only CharBuffer .

• By calling the asCharBuffer( ) method of a ByteBuffer to obtain a CharBuffer "view" of the underlying bytes. If the underlying ByteBuffer is direct, then the CharBuffer view will also be direct.

Note that this class holds a sequence of 16-bit Unicode characters , and does not represent text in any other encoding. Classes in the java.nio.charset package can be used to encode a CharBuffer of Unicode characters into a ByteBuffer , or decode the bytes in a ByteBuffer into a CharBuffer of Unicode text. Java 5.0 supports Unicode supplementary characters that do not fit in 16 bits. See java.lang.Character for details. Note that CharBuffer does not include any utility methods for working with int codepoints or surrogate pairs.

Figure 13-4. java.nio.CharBuffer

 public abstract class  CharBuffer  extends Buffer  implements Comparable<CharBuffer>, Appendable, CharSequence, Readable {  // No Constructor   // Public Class Methods  public static CharBuffer  allocate  (int  capacity  );        public static CharBuffer  wrap  (char[ ]  array  );        public static CharBuffer  wrap  (CharSequence  csq  );        public static CharBuffer  wrap  (char[ ]  array  , int  offset  , int  length  );        public static CharBuffer  wrap  (CharSequence  csq  , int  start  , int  end  );  // Public Instance Methods   5.0  public CharBuffer  append  (char  c  );  5.0  public CharBuffer  append  (CharSequence  csq  );  5.0  public CharBuffer  append  (CharSequence  csq  , int  start  , int  end  );        public final char[ ]  array  ( );        public final int  arrayOffset  ( );        public abstract CharBuffer  asReadOnlyBuffer  ( );        public abstract CharBuffer  compact  ( );        public abstract CharBuffer  duplicate  ( );        public abstract char  get  ( );        public abstract char  get  (int  index  );        public CharBuffer  get  (char[ ]  dst  );        public CharBuffer  get  (char[ ]  dst  , int  offset  , int  length  );        public final boolean  hasArray  ( );        public abstract boolean  isDirect  ( );        public abstract ByteOrder  order  ( );        public final CharBuffer  put  (char[ ]  src  );        public CharBuffer  put  (CharBuffer  src  );        public final CharBuffer  put  (String  src  );        public abstract CharBuffer  put  (char  c  );        public abstract CharBuffer  put  (int  index  , char  c  );        public CharBuffer  put  (String  src  , int  start  , int  end  );        public CharBuffer  put  (char[ ]  src  , int  offset  , int  length  );        public abstract CharBuffer  slice  ( );  // Methods Implementing CharSequence  public final char  charAt  (int  index  );        public final int  length  ( );        public abstract CharSequence  subSequence  (int  start  , int  end  );        public String  toString  ( );  // Methods Implementing Comparable   5.0  public int  compareTo  (CharBuffer  that  );  // Methods Implementing Readable   5.0  public int  read  (CharBuffer  target  ) throws java.io.IOException;  // Public Methods Overriding Object  public boolean  equals  (Object  ob  );        public int  hashCode  ( );   } 

Passed To

java.io.Reader.read( ) , Readable.read( ) , java.nio.charset.Charset.encode( ) , java.nio.charset.CharsetDecoder.{decode( ) , decodeLoop( ) , flush( ) , implFlush( )} , java.nio.charset.CharsetEncoder.{encode( ) , encodeLoop( )}

Returned By

ByteBuffer.asCharBuffer( ) , java.nio.charset.Charset.decode( ) , java.nio.charset.CharsetDecoder.decode( )