java/6 : java/nio/charset/CharsetEncoder.java

CharsetEncoder
https://openjdk.java.net/
GPLv2 + Classpath Exception
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// -- This file was mechanically generated: Do not edit! -- //

package java.nio.charset;

import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.BufferOverflowException;
import java.nio.BufferUnderflowException;
import java.lang.ref.WeakReference;
import java.nio.charset.CoderMalfunctionError;                  // javadoc


An engine that can transform a sequence of sixteen-bit Unicode characters into a sequence of
bytes in a specific charset.

 The input character sequence is provided in a character buffer or a series
of such buffers.  The output byte sequence is written to a byte buffer
or a series of such buffers.  An encoder should always be used by making
the following sequence of method invocations, hereinafter referred to as an
encoding operation:

   Reset the encoder via the reset method, unless it has not been used before; 
   Invoke the encode method zero or more times, as long as additional input may be available, passing false for the
  endOfInput argument and filling the input buffer and flushing the
  output buffer between invocations; 
   Invoke the encode method one final time, passing true for the endOfInput argument; and then 
   Invoke the flush method so that the encoder can flush any internal state to the output buffer. 
 Each invocation of the encode method will encode as many characters as possible from the input buffer, writing the resulting bytes to the output buffer. The encode method returns when more input is required, when there is not enough room in the output buffer, or when an encoding error has occurred. In each case a CoderResult object is returned to describe the reason for termination. An invoker can examine this object and fill the input buffer, flush the output buffer, or attempt to recover from an encoding error, as appropriate, and try again. 
 There are two general types of encoding errors.  If the input character
sequence is not a legal sixteen-bit Unicode sequence then the input is considered malformed.  If
the input character sequence is legal but cannot be mapped to a valid
byte sequence in the given charset then an unmappable character has been encountered.

 How an encoding error is handled depends upon the action requested for that type of error, which is described by an instance of the CodingErrorAction class. The possible error actions are to ignore the erroneous input, report the error to the invoker via the returned CoderResult object, or replace the erroneous input with the current value of the replacement byte array. The replacement is initially set to the encoder's default replacement, which often (but not always) has the initial value { (byte)'?' }; its value may be changed via the 
replaceWith method. 
 The default action for malformed-input and unmappable-character errors is to report them. The malformed-input error action may be changed via the onMalformedInput method; the unmappable-character action may be changed via the onUnmappableCharacter method. 
 This class is designed to handle many of the details of the encoding process, including the implementation of error actions. An encoder for a specific charset, which is a concrete subclass of this class, need only implement the abstract encodeLoop method, which encapsulates the basic encoding loop. A subclass that maintains internal state should, additionally, override the implFlush and implReset methods. 
 Instances of this class are not safe for use by multiple concurrent
threads.  

Author: Mark Reinhold, JSR-51 Expert Group
See Also: ByteBuffer
CharBuffer
Charset
CharsetDecoder
Since: 1.4/**
 * An engine that can transform a sequence of sixteen-bit Unicode characters into a sequence of
 * bytes in a specific charset.
 *
 * <a name="steps">
 *
 * <p> The input character sequence is provided in a character buffer or a series
 * of such buffers.  The output byte sequence is written to a byte buffer
 * or a series of such buffers.  An encoder should always be used by making
 * the following sequence of method invocations, hereinafter referred to as an
 * <i>encoding operation</i>:
 *
 * <ol>
 *
 *   <li><p> Reset the encoder via the {@link #reset reset} method, unless it
 *   has not been used before; </p></li>
 *
 *   <li><p> Invoke the {@link #encode encode} method zero or more times, as
 *   long as additional input may be available, passing <tt>false</tt> for the
 *   <tt>endOfInput</tt> argument and filling the input buffer and flushing the
 *   output buffer between invocations; </p></li>
 *
 *   <li><p> Invoke the {@link #encode encode} method one final time, passing
 *   <tt>true</tt> for the <tt>endOfInput</tt> argument; and then </p></li>
 *
 *   <li><p> Invoke the {@link #flush flush} method so that the encoder can
 *   flush any internal state to the output buffer. </p></li>
 *
 * </ol>
 *
 * Each invocation of the {@link #encode encode} method will encode as many
 * characters as possible from the input buffer, writing the resulting bytes
 * to the output buffer.  The {@link #encode encode} method returns when more
 * input is required, when there is not enough room in the output buffer, or
 * when an encoding error has occurred.  In each case a {@link CoderResult}
 * object is returned to describe the reason for termination.  An invoker can
 * examine this object and fill the input buffer, flush the output buffer, or
 * attempt to recover from an encoding error, as appropriate, and try again.
 *
 * <a name="ce">
 *
 * <p> There are two general types of encoding errors.  If the input character
 * sequence is not a legal sixteen-bit Unicode sequence then the input is considered <i>malformed</i>.  If
 * the input character sequence is legal but cannot be mapped to a valid
 * byte sequence in the given charset then an <i>unmappable character</i> has been encountered.
 *
 * <a name="cae">
 *
 * <p> How an encoding error is handled depends upon the action requested for
 * that type of error, which is described by an instance of the {@link
 * CodingErrorAction} class.  The possible error actions are to {@link
 * CodingErrorAction#IGNORE </code>ignore<code>} the erroneous input, {@link
 * CodingErrorAction#REPORT </code>report<code>} the error to the invoker via
 * the returned {@link CoderResult} object, or {@link CodingErrorAction#REPLACE
 * </code>replace<code>} the erroneous input with the current value of the
 * replacement byte array.  The replacement
 *

 * is initially set to the encoder's default replacement, which often
 * (but not always) has the initial value&nbsp;<tt>{</tt>&nbsp;<tt>(byte)'?'</tt>&nbsp;<tt>}</tt>;




 *
 * its value may be changed via the {@link #replaceWith(byte[])
 * replaceWith} method.
 *
 * <p> The default action for malformed-input and unmappable-character errors
 * is to {@link CodingErrorAction#REPORT </code>report<code>} them.  The
 * malformed-input error action may be changed via the {@link
 * #onMalformedInput(CodingErrorAction) onMalformedInput} method; the
 * unmappable-character action may be changed via the {@link
 * #onUnmappableCharacter(CodingErrorAction) onUnmappableCharacter} method.
 *
 * <p> This class is designed to handle many of the details of the encoding
 * process, including the implementation of error actions.  An encoder for a
 * specific charset, which is a concrete subclass of this class, need only
 * implement the abstract {@link #encodeLoop encodeLoop} method, which
 * encapsulates the basic encoding loop.  A subclass that maintains internal
 * state should, additionally, override the {@link #implFlush implFlush} and
 * {@link #implReset implReset} methods.
 *
 * <p> Instances of this class are not safe for use by multiple concurrent
 * threads.  </p>
 *
 *
 * @author Mark Reinhold
 * @author JSR-51 Expert Group
 * @since 1.4
 *
 * @see ByteBuffer
 * @see CharBuffer
 * @see Charset
 * @see CharsetDecoder
 */

public abstract class CharsetEncoder {

    private final Charset charset;
    private final float averageBytesPerChar;
    private final float maxBytesPerChar;

    private byte[] replacement;
    private CodingErrorAction malformedInputAction
        = CodingErrorAction.REPORT;
    private CodingErrorAction unmappableCharacterAction
        = CodingErrorAction.REPORT;

    // Internal states
    //
    private static final int ST_RESET   = 0;
    private static final int ST_CODING  = 1;
    private static final int ST_END     = 2;
    private static final int ST_FLUSHED = 3;

    private int state = ST_RESET;

    private static String stateNames[]
        = { "RESET", "CODING", "CODING_END", "FLUSHED" };


    Initializes a new encoder.  The new encoder will have the given
bytes-per-char and replacement values. 
Params: averageBytesPerChar – 
        A positive float value indicating the expected number of
        bytes that will be produced for each input character
maxBytesPerChar – 
        A positive float value indicating the maximum number of
        bytes that will be produced for each input character
replacement – 
        The initial replacement; must not be null, must have non-zero length, must not be longer than maxBytesPerChar, and must be legal
Throws: IllegalArgumentException – 
         If the preconditions on the parameters do not hold/**
     * Initializes a new encoder.  The new encoder will have the given
     * bytes-per-char and replacement values. </p>
     *
     * @param  averageBytesPerChar
     *         A positive float value indicating the expected number of
     *         bytes that will be produced for each input character
     *
     * @param  maxBytesPerChar
     *         A positive float value indicating the maximum number of
     *         bytes that will be produced for each input character
     *
     * @param  replacement
     *         The initial replacement; must not be <tt>null</tt>, must have
     *         non-zero length, must not be longer than maxBytesPerChar,
     *         and must be {@link #isLegalReplacement </code>legal<code>}
     *
     * @throws  IllegalArgumentException
     *          If the preconditions on the parameters do not hold
     */
    protected
    CharsetEncoder(Charset cs,
                   float averageBytesPerChar,
                   float maxBytesPerChar,
                   byte[] replacement)
    {
        this.charset = cs;
        if (averageBytesPerChar <= 0.0f)
            throw new IllegalArgumentException("Non-positive "
                                               + "averageBytesPerChar");
        if (maxBytesPerChar <= 0.0f)
            throw new IllegalArgumentException("Non-positive "
                                               + "maxBytesPerChar");
        if (!Charset.atBugLevel("1.4")) {
            if (averageBytesPerChar > maxBytesPerChar)
                throw new IllegalArgumentException("averageBytesPerChar"
                                                   + " exceeds "
                                                   + "maxBytesPerChar");
        }
        this.replacement = replacement;
        this.averageBytesPerChar = averageBytesPerChar;
        this.maxBytesPerChar = maxBytesPerChar;
        replaceWith(replacement);
    }

    Initializes a new encoder.  The new encoder will have the given
bytes-per-char values and its replacement will be the
byte array { (byte)'?' }. 
Params: averageBytesPerChar – 
        A positive float value indicating the expected number of
        bytes that will be produced for each input character
maxBytesPerChar – 
        A positive float value indicating the maximum number of
        bytes that will be produced for each input character
Throws: IllegalArgumentException – 
         If the preconditions on the parameters do not hold/**
     * Initializes a new encoder.  The new encoder will have the given
     * bytes-per-char values and its replacement will be the
     * byte array <tt>{</tt>&nbsp;<tt>(byte)'?'</tt>&nbsp;<tt>}</tt>. </p>
     *
     * @param  averageBytesPerChar
     *         A positive float value indicating the expected number of
     *         bytes that will be produced for each input character
     *
     * @param  maxBytesPerChar
     *         A positive float value indicating the maximum number of
     *         bytes that will be produced for each input character
     *
     * @throws  IllegalArgumentException
     *          If the preconditions on the parameters do not hold
     */
    protected CharsetEncoder(Charset cs,
                             float averageBytesPerChar,
                             float maxBytesPerChar)
    {
        this(cs,
             averageBytesPerChar, maxBytesPerChar,
             new byte[] { (byte)'?' });
    }

    Returns the charset that created this encoder.  
Returns:  This encoder's charset/**
     * Returns the charset that created this encoder.  </p>
     *
     * @return  This encoder's charset
     */
    public final Charset charset() {
        return charset;
    }

    Returns this encoder's replacement value. 
Returns:  This encoder's current replacement,
         which is never null and is never empty/**
     * Returns this encoder's replacement value. </p>
     *
     * @return  This encoder's current replacement,
     *          which is never <tt>null</tt> and is never empty
     */
    public final byte[] replacement() {
        return replacement;
    }

    Changes this encoder's replacement value.
 This method invokes the implReplaceWith method, passing the new replacement, after checking that the new replacement is acceptable. 
Params: newReplacement – 
        The new replacement; must not be null, must have non-zero length, must not be longer than the value returned by the maxBytesPerChar method, and must be legal
Throws: IllegalArgumentException – 
         If the preconditions on the parameter do not hold
Returns:  This encoder/**
     * Changes this encoder's replacement value.
     *
     * <p> This method invokes the {@link #implReplaceWith implReplaceWith}
     * method, passing the new replacement, after checking that the new
     * replacement is acceptable.  </p>
     *
     * @param  newReplacement
     *





     *         The new replacement; must not be <tt>null</tt>, must have
     *         non-zero length, must not be longer than the value returned by
     *         the {@link #maxBytesPerChar() maxBytesPerChar} method, and
     *         must be {@link #isLegalReplacement </code>legal<code>}

     *
     * @return  This encoder
     *
     * @throws  IllegalArgumentException
     *          If the preconditions on the parameter do not hold
     */
    public final CharsetEncoder replaceWith(byte[] newReplacement) {
        if (newReplacement == null)
            throw new IllegalArgumentException("Null replacement");
        int len = newReplacement.length;
        if (len == 0)
            throw new IllegalArgumentException("Empty replacement");
        if (len > maxBytesPerChar)
            throw new IllegalArgumentException("Replacement too long");

        if (!isLegalReplacement(newReplacement))
            throw new IllegalArgumentException("Illegal replacement");

        this.replacement = newReplacement;
        implReplaceWith(newReplacement);
        return this;
    }

    Reports a change to this encoder's replacement value.
 The default implementation of this method does nothing.  This method
should be overridden by encoders that require notification of changes to
the replacement.  
Params: newReplacement – /**
     * Reports a change to this encoder's replacement value.
     *
     * <p> The default implementation of this method does nothing.  This method
     * should be overridden by encoders that require notification of changes to
     * the replacement.  </p>
     *
     * @param  newReplacement
     */
    protected void implReplaceWith(byte[] newReplacement) {
    }



    private WeakReference<CharsetDecoder> cachedDecoder = null;

    Tells whether or not the given byte array is a legal replacement value
for this encoder.
 A replacement is legal if, and only if, it is a legal sequence of
bytes in this encoder's charset; that is, it must be possible to decode
the replacement into one or more sixteen-bit Unicode characters.
 The default implementation of this method is not very efficient; it
should generally be overridden to improve performance.  
Params: repl –  The byte array to be tested
Returns:  true if, and only if, the given byte array
         is a legal replacement value for this encoder/**
     * Tells whether or not the given byte array is a legal replacement value
     * for this encoder.
     *
     * <p> A replacement is legal if, and only if, it is a legal sequence of
     * bytes in this encoder's charset; that is, it must be possible to decode
     * the replacement into one or more sixteen-bit Unicode characters.
     *
     * <p> The default implementation of this method is not very efficient; it
     * should generally be overridden to improve performance.  </p>
     *
     * @param  repl  The byte array to be tested
     *
     * @return  <tt>true</tt> if, and only if, the given byte array
     *          is a legal replacement value for this encoder
     */
    public boolean isLegalReplacement(byte[] repl) {
        WeakReference<CharsetDecoder> wr = cachedDecoder;
        CharsetDecoder dec = null;
        if ((wr == null) || ((dec = wr.get()) == null)) {
            dec = charset().newDecoder();
            dec.onMalformedInput(CodingErrorAction.REPORT);
            dec.onUnmappableCharacter(CodingErrorAction.REPORT);
            cachedDecoder = new WeakReference<CharsetDecoder>(dec);
        } else {
            dec.reset();
        }
        ByteBuffer bb = ByteBuffer.wrap(repl);
        CharBuffer cb = CharBuffer.allocate((int)(bb.remaining()
                                                  * dec.maxCharsPerByte()));
        CoderResult cr = dec.decode(bb, cb, true);
        return !cr.isError();
    }



    Returns this encoder's current action for malformed-input errors.  
Returns: The current malformed-input action, which is never null/**
     * Returns this encoder's current action for malformed-input errors.  </p>
     *
     * @return The current malformed-input action, which is never <tt>null</tt>
     */
    public CodingErrorAction malformedInputAction() {
        return malformedInputAction;
    }

    Changes this encoder's action for malformed-input errors.  
 This method invokes the 
implOnMalformedInput method, passing the new action. 
Params: newAction –  The new action; must not be null
Throws: IllegalArgumentException – 
        If the precondition on the parameter does not hold
Returns:  This encoder/**
     * Changes this encoder's action for malformed-input errors.  </p>
     *
     * <p> This method invokes the {@link #implOnMalformedInput
     * implOnMalformedInput} method, passing the new action.  </p>
     *
     * @param  newAction  The new action; must not be <tt>null</tt>
     *
     * @return  This encoder
     *
     * @throws IllegalArgumentException
     *         If the precondition on the parameter does not hold
     */
    public final CharsetEncoder onMalformedInput(CodingErrorAction newAction) {
        if (newAction == null)
            throw new IllegalArgumentException("Null action");
        malformedInputAction = newAction;
        implOnMalformedInput(newAction);
        return this;
    }

    Reports a change to this encoder's malformed-input action.
 The default implementation of this method does nothing.  This method
should be overridden by encoders that require notification of changes to
the malformed-input action.  
/**
     * Reports a change to this encoder's malformed-input action.
     *
     * <p> The default implementation of this method does nothing.  This method
     * should be overridden by encoders that require notification of changes to
     * the malformed-input action.  </p>
     */
    protected void implOnMalformedInput(CodingErrorAction newAction) { }

    Returns this encoder's current action for unmappable-character errors.

Returns: The current unmappable-character action, which is never
        null/**
     * Returns this encoder's current action for unmappable-character errors.
     * </p>
     *
     * @return The current unmappable-character action, which is never
     *         <tt>null</tt>
     */
    public CodingErrorAction unmappableCharacterAction() {
        return unmappableCharacterAction;
    }

    Changes this encoder's action for unmappable-character errors.
 This method invokes the 
implOnUnmappableCharacter method, passing the new action. 
Params: newAction –  The new action; must not be null
Throws: IllegalArgumentException – 
        If the precondition on the parameter does not hold
Returns:  This encoder/**
     * Changes this encoder's action for unmappable-character errors.
     *
     * <p> This method invokes the {@link #implOnUnmappableCharacter
     * implOnUnmappableCharacter} method, passing the new action.  </p>
     *
     * @param  newAction  The new action; must not be <tt>null</tt>
     *
     * @return  This encoder
     *
     * @throws IllegalArgumentException
     *         If the precondition on the parameter does not hold
     */
    public final CharsetEncoder onUnmappableCharacter(CodingErrorAction
                                                      newAction)
    {
        if (newAction == null)
            throw new IllegalArgumentException("Null action");
        unmappableCharacterAction = newAction;
        implOnUnmappableCharacter(newAction);
        return this;
    }

    Reports a change to this encoder's unmappable-character action.
 The default implementation of this method does nothing.  This method
should be overridden by encoders that require notification of changes to
the unmappable-character action.  
/**
     * Reports a change to this encoder's unmappable-character action.
     *
     * <p> The default implementation of this method does nothing.  This method
     * should be overridden by encoders that require notification of changes to
     * the unmappable-character action.  </p>
     */
    protected void implOnUnmappableCharacter(CodingErrorAction newAction) { }

    Returns the average number of bytes that will be produced for each
character of input.  This heuristic value may be used to estimate the size
of the output buffer required for a given input sequence. 
Returns:  The average number of bytes produced
         per character of input/**
     * Returns the average number of bytes that will be produced for each
     * character of input.  This heuristic value may be used to estimate the size
     * of the output buffer required for a given input sequence. </p>
     *
     * @return  The average number of bytes produced
     *          per character of input
     */
    public final float averageBytesPerChar() {
        return averageBytesPerChar;
    }

    Returns the maximum number of bytes that will be produced for each
character of input.  This value may be used to compute the worst-case size
of the output buffer required for a given input sequence. 
Returns:  The maximum number of bytes that will be produced per
         character of input/**
     * Returns the maximum number of bytes that will be produced for each
     * character of input.  This value may be used to compute the worst-case size
     * of the output buffer required for a given input sequence. </p>
     *
     * @return  The maximum number of bytes that will be produced per
     *          character of input
     */
    public final float maxBytesPerChar() {
        return maxBytesPerChar;
    }

    Encodes as many characters as possible from the given input buffer,
writing the results to the given output buffer.
 The buffers are read from, and written to, starting at their current positions. At most in.remaining() characters will be read and at most out.remaining() bytes will be written. The buffers' positions will be advanced to reflect the characters read and the bytes written, but their marks and limits will not be modified. 
 In addition to reading characters from the input buffer and writing bytes to the output buffer, this method returns a CoderResult object to describe its reason for termination: 

   CoderResult.UNDERFLOW indicates that as much of the input buffer as possible has been encoded. If there is no further input then the invoker can proceed to the next step of the encoding operation.  Otherwise this method
  should be invoked again with further input.  
   CoderResult.OVERFLOW indicates that there is insufficient space in the output buffer to encode any more characters. This method should be invoked again with an output buffer that has more remaining bytes. This is typically done by draining any encoded bytes from the output buffer. 
   A malformed-input result indicates that a malformed-input error has been detected. The malformed characters begin at the input buffer's (possibly incremented) position; the number of malformed characters may be determined by invoking the result object's length method. This case applies only if the malformed action of this encoder is CodingErrorAction.REPORT; otherwise the malformed input will be ignored or replaced, as requested. 
   An unmappable-character result indicates that an unmappable-character error has been detected. The characters that encode the unmappable character begin at the input buffer's (possibly incremented) position; the number of such characters may be determined by invoking the result object's length method. This case applies only if the unmappable action of this encoder is CodingErrorAction.REPORT; otherwise the unmappable character will be ignored or replaced, as requested. 

In any case, if this method is to be reinvoked in the same encoding
operation then care should be taken to preserve any characters remaining
in the input buffer so that they are available to the next invocation.
 The endOfInput parameter advises this method as to whether
the invoker can provide further input beyond that contained in the given
input buffer.  If there is a possibility of providing additional input
then the invoker should pass false for this parameter; if there
is no possibility of providing further input then the invoker should
pass true.  It is not erroneous, and in fact it is quite
common, to pass false in one invocation and later discover that
no further input was actually available.  It is critical, however, that
the final invocation of this method in a sequence of invocations always
pass true so that any remaining unencoded input will be treated
as being malformed.
 This method works by invoking the encodeLoop method, interpreting its results, handling error conditions, and reinvoking it as necessary. 
Params: in – 
        The input character buffer
out – 
        The output byte buffer
endOfInput – 
        true if, and only if, the invoker can provide no
        additional input characters beyond those in the given buffer
Throws: IllegalStateException –  If an encoding operation is already in progress and the previous step was an invocation neither of the reset method, nor of this method with a value of false for
         the endOfInput parameter, nor of this method with a
         value of true for the endOfInput parameter
         but a return value indicating an incomplete encoding operation
CoderMalfunctionError – 
         If an invocation of the encodeLoop method threw
         an unexpected exception
Returns:  A coder-result object describing the reason for termination/**
     * Encodes as many characters as possible from the given input buffer,
     * writing the results to the given output buffer.
     *
     * <p> The buffers are read from, and written to, starting at their current
     * positions.  At most {@link Buffer#remaining in.remaining()} characters
     * will be read and at most {@link Buffer#remaining out.remaining()}
     * bytes will be written.  The buffers' positions will be advanced to
     * reflect the characters read and the bytes written, but their marks and
     * limits will not be modified.
     *
     * <p> In addition to reading characters from the input buffer and writing
     * bytes to the output buffer, this method returns a {@link CoderResult}
     * object to describe its reason for termination:
     *
     * <ul>
     *
     *   <li><p> {@link CoderResult#UNDERFLOW} indicates that as much of the
     *   input buffer as possible has been encoded.  If there is no further
     *   input then the invoker can proceed to the next step of the
     *   <a href="#steps">encoding operation</a>.  Otherwise this method
     *   should be invoked again with further input.  </p></li>
     *
     *   <li><p> {@link CoderResult#OVERFLOW} indicates that there is
     *   insufficient space in the output buffer to encode any more characters.
     *   This method should be invoked again with an output buffer that has
     *   more {@linkplain Buffer#remaining remaining} bytes. This is
     *   typically done by draining any encoded bytes from the output
     *   buffer.  </p></li>
     *
     *   <li><p> A {@link CoderResult#malformedForLength
     *   </code>malformed-input<code>} result indicates that a malformed-input
     *   error has been detected.  The malformed characters begin at the input
     *   buffer's (possibly incremented) position; the number of malformed
     *   characters may be determined by invoking the result object's {@link
     *   CoderResult#length() length} method.  This case applies only if the
     *   {@link #onMalformedInput </code>malformed action<code>} of this encoder
     *   is {@link CodingErrorAction#REPORT}; otherwise the malformed input
     *   will be ignored or replaced, as requested.  </p></li>
     *
     *   <li><p> An {@link CoderResult#unmappableForLength
     *   </code>unmappable-character<code>} result indicates that an
     *   unmappable-character error has been detected.  The characters that
     *   encode the unmappable character begin at the input buffer's (possibly
     *   incremented) position; the number of such characters may be determined
     *   by invoking the result object's {@link CoderResult#length() length}
     *   method.  This case applies only if the {@link #onUnmappableCharacter
     *   </code>unmappable action<code>} of this encoder is {@link
     *   CodingErrorAction#REPORT}; otherwise the unmappable character will be
     *   ignored or replaced, as requested.  </p></li>
     *
     * </ul>
     *
     * In any case, if this method is to be reinvoked in the same encoding
     * operation then care should be taken to preserve any characters remaining
     * in the input buffer so that they are available to the next invocation.
     *
     * <p> The <tt>endOfInput</tt> parameter advises this method as to whether
     * the invoker can provide further input beyond that contained in the given
     * input buffer.  If there is a possibility of providing additional input
     * then the invoker should pass <tt>false</tt> for this parameter; if there
     * is no possibility of providing further input then the invoker should
     * pass <tt>true</tt>.  It is not erroneous, and in fact it is quite
     * common, to pass <tt>false</tt> in one invocation and later discover that
     * no further input was actually available.  It is critical, however, that
     * the final invocation of this method in a sequence of invocations always
     * pass <tt>true</tt> so that any remaining unencoded input will be treated
     * as being malformed.
     *
     * <p> This method works by invoking the {@link #encodeLoop encodeLoop}
     * method, interpreting its results, handling error conditions, and
     * reinvoking it as necessary.  </p>
     *
     *
     * @param  in
     *         The input character buffer
     *
     * @param  out
     *         The output byte buffer
     *
     * @param  endOfInput
     *         <tt>true</tt> if, and only if, the invoker can provide no
     *         additional input characters beyond those in the given buffer
     *
     * @return  A coder-result object describing the reason for termination
     *
     * @throws  IllegalStateException
     *          If an encoding operation is already in progress and the previous
     *          step was an invocation neither of the {@link #reset reset}
     *          method, nor of this method with a value of <tt>false</tt> for
     *          the <tt>endOfInput</tt> parameter, nor of this method with a
     *          value of <tt>true</tt> for the <tt>endOfInput</tt> parameter
     *          but a return value indicating an incomplete encoding operation
     *
     * @throws  CoderMalfunctionError
     *          If an invocation of the encodeLoop method threw
     *          an unexpected exception
     */
    public final CoderResult encode(CharBuffer in, ByteBuffer out,
                                    boolean endOfInput)
    {
        int newState = endOfInput ? ST_END : ST_CODING;
        if ((state != ST_RESET) && (state != ST_CODING)
            && !(endOfInput && (state == ST_END)))
            throwIllegalStateException(state, newState);
        state = newState;

        for (;;) {

            CoderResult cr;
            try {
                cr = encodeLoop(in, out);
            } catch (BufferUnderflowException x) {
                throw new CoderMalfunctionError(x);
            } catch (BufferOverflowException x) {
                throw new CoderMalfunctionError(x);
            }

            if (cr.isOverflow())
                return cr;

            if (cr.isUnderflow()) {
                if (endOfInput && in.hasRemaining()) {
                    cr = CoderResult.malformedForLength(in.remaining());
                    // Fall through to malformed-input case
                } else {
                    return cr;
                }
            }

            CodingErrorAction action = null;
            if (cr.isMalformed())
                action = malformedInputAction;
            else if (cr.isUnmappable())
                action = unmappableCharacterAction;
            else
                assert false : cr.toString();

            if (action == CodingErrorAction.REPORT)
                return cr;

            if (action == CodingErrorAction.REPLACE) {
                if (out.remaining() < replacement.length)
                    return CoderResult.OVERFLOW;
                out.put(replacement);
            }

            if ((action == CodingErrorAction.IGNORE)
                || (action == CodingErrorAction.REPLACE)) {
                // Skip erroneous input either way
                in.position(in.position() + cr.length());
                continue;
            }

            assert false;
        }

    }

    Flushes this encoder.
 Some encoders maintain internal state and may need to write some
final bytes to the output buffer once the overall input sequence has
been read.
 Any additional output is written to the output buffer beginning at its current position. At most out.remaining() bytes will be written. The buffer's position will be advanced appropriately, but its mark and limit will not be modified. 
 If this method completes successfully then it returns CoderResult.UNDERFLOW. If there is insufficient room in the output buffer then it returns CoderResult.OVERFLOW. If this happens then this method must be invoked again, with an output buffer that has more room, in order to complete the current encoding
operation.
 If this encoder has already been flushed then invoking this method
has no effect.
 This method invokes the implFlush method to perform the actual flushing operation. 
Params: out – 
        The output byte buffer
Throws: IllegalStateException –  If the previous step of the current encoding operation was an invocation neither of the flush method nor of the three-argument encode method with a value of true for the endOfInput
         parameter
Returns:  A coder-result object, either CoderResult.UNDERFLOW or CoderResult.OVERFLOW/**
     * Flushes this encoder.
     *
     * <p> Some encoders maintain internal state and may need to write some
     * final bytes to the output buffer once the overall input sequence has
     * been read.
     *
     * <p> Any additional output is written to the output buffer beginning at
     * its current position.  At most {@link Buffer#remaining out.remaining()}
     * bytes will be written.  The buffer's position will be advanced
     * appropriately, but its mark and limit will not be modified.
     *
     * <p> If this method completes successfully then it returns {@link
     * CoderResult#UNDERFLOW}.  If there is insufficient room in the output
     * buffer then it returns {@link CoderResult#OVERFLOW}.  If this happens
     * then this method must be invoked again, with an output buffer that has
     * more room, in order to complete the current <a href="#steps">encoding
     * operation</a>.
     *
     * <p> If this encoder has already been flushed then invoking this method
     * has no effect.
     *
     * <p> This method invokes the {@link #implFlush implFlush} method to
     * perform the actual flushing operation.  </p>
     *
     * @param  out
     *         The output byte buffer
     *
     * @return  A coder-result object, either {@link CoderResult#UNDERFLOW} or
     *          {@link CoderResult#OVERFLOW}
     *
     * @throws  IllegalStateException
     *          If the previous step of the current encoding operation was an
     *          invocation neither of the {@link #flush flush} method nor of
     *          the three-argument {@link
     *          #encode(CharBuffer,ByteBuffer,boolean) encode} method
     *          with a value of <tt>true</tt> for the <tt>endOfInput</tt>
     *          parameter
     */
    public final CoderResult flush(ByteBuffer out) {
        if (state == ST_END) {
            CoderResult cr = implFlush(out);
            if (cr.isUnderflow())
                state = ST_FLUSHED;
            return cr;
        }

        if (state != ST_FLUSHED)
            throwIllegalStateException(state, ST_FLUSHED);

        return CoderResult.UNDERFLOW; // Already flushed
    }

    Flushes this encoder.
 The default implementation of this method does nothing, and always returns CoderResult.UNDERFLOW. This method should be overridden by encoders that may need to write final bytes to the output buffer once the entire input sequence has been read. 
Params: out – 
        The output byte buffer
Returns:  A coder-result object, either CoderResult.UNDERFLOW or CoderResult.OVERFLOW/**
     * Flushes this encoder.
     *
     * <p> The default implementation of this method does nothing, and always
     * returns {@link CoderResult#UNDERFLOW}.  This method should be overridden
     * by encoders that may need to write final bytes to the output buffer
     * once the entire input sequence has been read. </p>
     *
     * @param  out
     *         The output byte buffer
     *
     * @return  A coder-result object, either {@link CoderResult#UNDERFLOW} or
     *          {@link CoderResult#OVERFLOW}
     */
    protected CoderResult implFlush(ByteBuffer out) {
        return CoderResult.UNDERFLOW;
    }

    Resets this encoder, clearing any internal state.
 This method resets charset-independent state and also invokes the implReset method in order to perform any charset-specific reset actions. 
Returns:  This encoder/**
     * Resets this encoder, clearing any internal state.
     *
     * <p> This method resets charset-independent state and also invokes the
     * {@link #implReset() implReset} method in order to perform any
     * charset-specific reset actions.  </p>
     *
     * @return  This encoder
     *
     */
    public final CharsetEncoder reset() {
        implReset();
        state = ST_RESET;
        return this;
    }

    Resets this encoder, clearing any charset-specific internal state.
 The default implementation of this method does nothing.  This method
should be overridden by encoders that maintain internal state.  
/**
     * Resets this encoder, clearing any charset-specific internal state.
     *
     * <p> The default implementation of this method does nothing.  This method
     * should be overridden by encoders that maintain internal state.  </p>
     */
    protected void implReset() { }

    Encodes one or more characters into one or more bytes.
 This method encapsulates the basic encoding loop, encoding as many characters as possible until it either runs out of input, runs out of room in the output buffer, or encounters an encoding error. This method is invoked by the encode method, which handles result interpretation and error recovery. 
 The buffers are read from, and written to, starting at their current positions. At most in.remaining() characters will be read, and at most out.remaining() bytes will be written. The buffers' positions will be advanced to reflect the characters read and the bytes written, but their marks and limits will not be modified. 
 This method returns a CoderResult object to describe its reason for termination, in the same manner as the encode method. Most implementations of this method will handle encoding errors by returning an appropriate result object for interpretation by the encode method. An optimized implementation may instead examine the relevant error action and implement that action itself. 
 An implementation of this method may perform arbitrary lookahead by returning CoderResult.UNDERFLOW until it receives sufficient input. 
Params: in – 
        The input character buffer
out – 
        The output byte buffer
Returns:  A coder-result object describing the reason for termination/**
     * Encodes one or more characters into one or more bytes.
     *
     * <p> This method encapsulates the basic encoding loop, encoding as many
     * characters as possible until it either runs out of input, runs out of room
     * in the output buffer, or encounters an encoding error.  This method is
     * invoked by the {@link #encode encode} method, which handles result
     * interpretation and error recovery.
     *
     * <p> The buffers are read from, and written to, starting at their current
     * positions.  At most {@link Buffer#remaining in.remaining()} characters
     * will be read, and at most {@link Buffer#remaining out.remaining()}
     * bytes will be written.  The buffers' positions will be advanced to
     * reflect the characters read and the bytes written, but their marks and
     * limits will not be modified.
     *
     * <p> This method returns a {@link CoderResult} object to describe its
     * reason for termination, in the same manner as the {@link #encode encode}
     * method.  Most implementations of this method will handle encoding errors
     * by returning an appropriate result object for interpretation by the
     * {@link #encode encode} method.  An optimized implementation may instead
     * examine the relevant error action and implement that action itself.
     *
     * <p> An implementation of this method may perform arbitrary lookahead by
     * returning {@link CoderResult#UNDERFLOW} until it receives sufficient
     * input.  </p>
     *
     * @param  in
     *         The input character buffer
     *
     * @param  out
     *         The output byte buffer
     *
     * @return  A coder-result object describing the reason for termination
     */
    protected abstract CoderResult encodeLoop(CharBuffer in,
                                              ByteBuffer out);

    Convenience method that encodes the remaining content of a single input
character buffer into a newly-allocated byte buffer.
 This method implements an entire encoding
operation; that is, it resets this encoder, then it encodes the
characters in the given character buffer, and finally it flushes this
encoder.  This method should therefore not be invoked if an encoding
operation is already in progress.  
Params: in – 
        The input character buffer
Throws: IllegalStateException – 
         If an encoding operation is already in progress
MalformedInputException –  If the character sequence starting at the input buffer's current position is not a legal sixteen-bit Unicode sequence and the current malformed-input action is CodingErrorAction.REPORT
UnmappableCharacterException –  If the character sequence starting at the input buffer's current position cannot be mapped to an equivalent byte sequence and the current unmappable-character action is CodingErrorAction.REPORT
Returns: A newly-allocated byte buffer containing the result of the
        encoding operation.  The buffer's position will be zero and its
        limit will follow the last byte written./**
     * Convenience method that encodes the remaining content of a single input
     * character buffer into a newly-allocated byte buffer.
     *
     * <p> This method implements an entire <a href="#steps">encoding
     * operation</a>; that is, it resets this encoder, then it encodes the
     * characters in the given character buffer, and finally it flushes this
     * encoder.  This method should therefore not be invoked if an encoding
     * operation is already in progress.  </p>
     *
     * @param  in
     *         The input character buffer
     *
     * @return A newly-allocated byte buffer containing the result of the
     *         encoding operation.  The buffer's position will be zero and its
     *         limit will follow the last byte written.
     *
     * @throws  IllegalStateException
     *          If an encoding operation is already in progress
     *
     * @throws  MalformedInputException
     *          If the character sequence starting at the input buffer's current
     *          position is not a legal sixteen-bit Unicode sequence and the current malformed-input action
     *          is {@link CodingErrorAction#REPORT}
     *
     * @throws  UnmappableCharacterException
     *          If the character sequence starting at the input buffer's current
     *          position cannot be mapped to an equivalent byte sequence and
     *          the current unmappable-character action is {@link
     *          CodingErrorAction#REPORT}
     */
    public final ByteBuffer encode(CharBuffer in)
        throws CharacterCodingException
    {
        int n = (int)(in.remaining() * averageBytesPerChar());
        ByteBuffer out = ByteBuffer.allocate(n);

        if ((n == 0) && (in.remaining() == 0))
            return out;
        reset();
        for (;;) {
            CoderResult cr = in.hasRemaining() ?
                encode(in, out, true) : CoderResult.UNDERFLOW;
            if (cr.isUnderflow())
                cr = flush(out);

            if (cr.isUnderflow())
                break;
            if (cr.isOverflow()) {
                n = 2*n + 1;    // Ensure progress; n might be 0!
                ByteBuffer o = ByteBuffer.allocate(n);
                out.flip();
                o.put(out);
                out = o;
                continue;
            }
            cr.throwException();
        }
        out.flip();
        return out;
    }















































































    private boolean canEncode(CharBuffer cb) {
        if (state == ST_FLUSHED)
            reset();
        else if (state != ST_RESET)
            throwIllegalStateException(state, ST_CODING);
        CodingErrorAction ma = malformedInputAction();
        CodingErrorAction ua = unmappableCharacterAction();
        try {
            onMalformedInput(CodingErrorAction.REPORT);
            onUnmappableCharacter(CodingErrorAction.REPORT);
            encode(cb);
        } catch (CharacterCodingException x) {
            return false;
        } finally {
            onMalformedInput(ma);
            onUnmappableCharacter(ua);
            reset();
        }
        return true;
    }

    Tells whether or not this encoder can encode the given character.
 This method returns false if the given character is a surrogate character; such characters can be interpreted only when they are members of a pair consisting of a high surrogate followed by a low surrogate. The 
canEncode(CharSequence) method may be used to test whether or not a character sequence can be encoded. 
 This method may modify this encoder's state; it should therefore not
be invoked if an encoding operation is already in
progress.
 The default implementation of this method is not very efficient; it
should generally be overridden to improve performance.  
Throws: IllegalStateException – 
         If an encoding operation is already in progress
Returns:  true if, and only if, this encoder can encode
         the given character/**
     * Tells whether or not this encoder can encode the given character.
     *
     * <p> This method returns <tt>false</tt> if the given character is a
     * surrogate character; such characters can be interpreted only when they
     * are members of a pair consisting of a high surrogate followed by a low
     * surrogate.  The {@link #canEncode(java.lang.CharSequence)
     * canEncode(CharSequence)} method may be used to test whether or not a
     * character sequence can be encoded.
     *
     * <p> This method may modify this encoder's state; it should therefore not
     * be invoked if an <a href="#steps">encoding operation</a> is already in
     * progress.
     *
     * <p> The default implementation of this method is not very efficient; it
     * should generally be overridden to improve performance.  </p>
     *
     * @return  <tt>true</tt> if, and only if, this encoder can encode
     *          the given character
     *
     * @throws  IllegalStateException
     *          If an encoding operation is already in progress
     */
    public boolean canEncode(char c) {
        CharBuffer cb = CharBuffer.allocate(1);
        cb.put(c);
        cb.flip();
        return canEncode(cb);
    }

    Tells whether or not this encoder can encode the given character
sequence.
 If this method returns false for a particular character
sequence then more information about why the sequence cannot be encoded
may be obtained by performing a full encoding
operation.
 This method may modify this encoder's state; it should therefore not
be invoked if an encoding operation is already in progress.
 The default implementation of this method is not very efficient; it
should generally be overridden to improve performance.  
Throws: IllegalStateException – 
         If an encoding operation is already in progress
Returns:  true if, and only if, this encoder can encode
         the given character without throwing any exceptions and without
         performing any replacements/**
     * Tells whether or not this encoder can encode the given character
     * sequence.
     *
     * <p> If this method returns <tt>false</tt> for a particular character
     * sequence then more information about why the sequence cannot be encoded
     * may be obtained by performing a full <a href="#steps">encoding
     * operation</a>.
     *
     * <p> This method may modify this encoder's state; it should therefore not
     * be invoked if an encoding operation is already in progress.
     *
     * <p> The default implementation of this method is not very efficient; it
     * should generally be overridden to improve performance.  </p>
     *
     * @return  <tt>true</tt> if, and only if, this encoder can encode
     *          the given character without throwing any exceptions and without
     *          performing any replacements
     *
     * @throws  IllegalStateException
     *          If an encoding operation is already in progress
     */
    public boolean canEncode(CharSequence cs) {
        CharBuffer cb;
        if (cs instanceof CharBuffer)
            cb = ((CharBuffer)cs).duplicate();
        else
            cb = CharBuffer.wrap(cs.toString());
        return canEncode(cb);
    }




    private void throwIllegalStateException(int from, int to) {
        throw new IllegalStateException("Current state = " + stateNames[from]
                                        + ", new state = " + stateNames[to]);
    }

}
Author:	Mark Reinhold, JSR-51 Expert Group
See Also:	ByteBuffer CharBuffer Charset CharsetDecoder
Since:	1.4
Params:	averageBytesPerChar – A positive float value indicating the expected number of bytes that will be produced for each input character maxBytesPerChar – A positive float value indicating the maximum number of bytes that will be produced for each input character
Throws:	IllegalArgumentException – If the preconditions on the parameters do not hold
Params:	newReplacement – The new replacement; must not be `null`, must have non-zero length, must not be longer than the value returned by the `maxBytesPerChar` method, and must be `legal`
Throws:	IllegalArgumentException – If the preconditions on the parameter do not hold
Returns:	This encoder
Params:	repl – The byte array to be tested
Returns:	`true` if, and only if, the given byte array is a legal replacement value for this encoder
Params:	newAction – The new action; must not be `null`
Throws:	IllegalArgumentException – If the precondition on the parameter does not hold
Returns:	This encoder
Params:	in – The input character buffer out – The output byte buffer endOfInput – `true` if, and only if, the invoker can provide no additional input characters beyond those in the given buffer
Throws:	IllegalStateException – If an encoding operation is already in progress and the previous step was an invocation neither of the `reset` method, nor of this method with a value of `false` for the `endOfInput` parameter, nor of this method with a value of `true` for the `endOfInput` parameter but a return value indicating an incomplete encoding operation CoderMalfunctionError – If an invocation of the encodeLoop method threw an unexpected exception
Returns:	A coder-result object describing the reason for termination
Params:	out – The output byte buffer
Throws:	IllegalStateException – If the previous step of the current encoding operation was an invocation neither of the `flush` method nor of the three-argument `encode` method with a value of `true` for the `endOfInput` parameter
Returns:	A coder-result object, either `CoderResult.UNDERFLOW` or `CoderResult.OVERFLOW`
Params:	in – The input character buffer
Throws:	IllegalStateException – If an encoding operation is already in progress MalformedInputException – If the character sequence starting at the input buffer's current position is not a legal sixteen-bit Unicode sequence and the current malformed-input action is `CodingErrorAction.REPORT` UnmappableCharacterException – If the character sequence starting at the input buffer's current position cannot be mapped to an equivalent byte sequence and the current unmappable-character action is `CodingErrorAction.REPORT`
Returns:	A newly-allocated byte buffer containing the result of the encoding operation. The buffer's position will be zero and its limit will follow the last byte written.
/

java/ 6/ java/nio/charset/CharsetEncoder.java
