/**@class java.nio.charset.CharsetDecoder @extends java.lang.Object An engine that can transform a sequence of bytes in a specific charset into a sequence of sixteen-bit Unicode characters. <a name="steps"></a> <p> The input byte sequence is provided in a byte buffer or a series of such buffers. The output character sequence is written to a character buffer or a series of such buffers. A decoder should always be used by making the following sequence of method invocations, hereinafter referred to as a <i>decoding operation</i>: <ol> <li><p> Reset the decoder via the {@link #reset reset} method, unless it has not been used before; </p></li> <li><p> Invoke the {@link #decode decode} 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 #decode decode} 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 decoder can flush any internal state to the output buffer. </p></li> </ol> Each invocation of the {@link #decode decode} method will decode as many bytes as possible from the input buffer, writing the resulting characters to the output buffer. The {@link #decode decode} method returns when more input is required, when there is not enough room in the output buffer, or when a decoding error has occurred. In each case a {@link java.nio.charset.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 a decoding error, as appropriate, and try again. <a name="ce"></a> <p> There are two general types of decoding errors. If the input byte sequence is not legal for this charset then the input is considered <i>malformed</i>. If the input byte sequence is legal but cannot be mapped to a valid Unicode character then an <i>unmappable character</i> has been encountered. <a name="cae"></a> <p> How a decoding error is handled depends upon the action requested for that type of error, which is described by an instance of the {@link java.nio.charset.CodingErrorAction} class. The possible error actions are to {@linkplain java.nio.charset.CodingErrorAction#IGNORE ignore} the erroneous input, {@linkplain java.nio.charset.CodingErrorAction#REPORT report} the error to the invoker via the returned {@link java.nio.charset.CoderResult} object, or {@linkplain java.nio.charset.CodingErrorAction#REPLACE replace} the erroneous input with the current value of the replacement string. The replacement has the initial value <tt>"\uFFFD"</tt>; its value may be changed via the {@link #replaceWith(java.lang.String) replaceWith} method. <p> The default action for malformed-input and unmappable-character errors is to {@linkplain java.nio.charset.CodingErrorAction#REPORT report} 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 decoding process, including the implementation of error actions. A decoder for a specific charset, which is a concrete subclass of this class, need only implement the abstract {@link #decodeLoop decodeLoop} method, which encapsulates the basic decoding 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 CharsetEncoder */ var CharsetDecoder = { /**Returns the charset that created this decoder. @return {Object {java.nio.charset.Charset}} This decoder's charset */ charset : function( ) {}, /**Returns this decoder's replacement value. @return {String} This decoder's current replacement, which is never <tt>null</tt> and is never empty */ replacement : function( ) {}, /**Changes this decoder'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 {String} newReplacement The replacement value The new replacement; must not be <tt>null</tt> and must have non-zero length @return {Object {java.nio.charset.CharsetDecoder}} This decoder @throws IllegalArgumentException If the preconditions on the parameter do not hold */ replaceWith : function( ) {}, /**Returns this decoder's current action for malformed-input errors. @return {Object {java.nio.charset.CodingErrorAction}} The current malformed-input action, which is never <tt>null</tt> */ malformedInputAction : function( ) {}, /**Changes this decoder's action for malformed-input errors. <p> This method invokes the {@link #implOnMalformedInput implOnMalformedInput} method, passing the new action. </p> @param {Object {CodingErrorAction}} newAction The new action; must not be <tt>null</tt> @return {Object {java.nio.charset.CharsetDecoder}} This decoder @throws IllegalArgumentException If the precondition on the parameter does not hold */ onMalformedInput : function( ) {}, /**Returns this decoder's current action for unmappable-character errors. @return {Object {java.nio.charset.CodingErrorAction}} The current unmappable-character action, which is never <tt>null</tt> */ unmappableCharacterAction : function( ) {}, /**Changes this decoder's action for unmappable-character errors. <p> This method invokes the {@link #implOnUnmappableCharacter implOnUnmappableCharacter} method, passing the new action. </p> @param {Object {CodingErrorAction}} newAction The new action; must not be <tt>null</tt> @return {Object {java.nio.charset.CharsetDecoder}} This decoder @throws IllegalArgumentException If the precondition on the parameter does not hold */ onUnmappableCharacter : function( ) {}, /**Returns the average number of characters that will be produced for each byte of input. This heuristic value may be used to estimate the size of the output buffer required for a given input sequence. @return {Number} The average number of characters produced per byte of input */ averageCharsPerByte : function( ) {}, /**Returns the maximum number of characters that will be produced for each byte of input. This value may be used to compute the worst-case size of the output buffer required for a given input sequence. @return {Number} The maximum number of characters that will be produced per byte of input */ maxCharsPerByte : function( ) {}, /**Decodes as many bytes 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()} bytes will be read and at most {@link Buffer#remaining out.remaining()} characters will be written. The buffers' positions will be advanced to reflect the bytes read and the characters written, but their marks and limits will not be modified. <p> In addition to reading bytes from the input buffer and writing characters to the output buffer, this method returns a {@link java.nio.charset.CoderResult} object to describe its reason for termination: <ul> <li><p> {@link java.nio.charset.CoderResult#UNDERFLOW} indicates that as much of the input buffer as possible has been decoded. If there is no further input then the invoker can proceed to the next step of the <a href="#steps">decoding operation</a>. Otherwise this method should be invoked again with further input. </p></li> <li><p> {@link java.nio.charset.CoderResult#OVERFLOW} indicates that there is insufficient space in the output buffer to decode any more bytes. This method should be invoked again with an output buffer that has more {@linkplain Buffer#remaining remaining} characters. This is typically done by draining any decoded characters from the output buffer. </p></li> <li><p> A {@linkplain java.nio.charset.CoderResult#malformedForLength malformed-input} result indicates that a malformed-input error has been detected. The malformed bytes begin at the input buffer's (possibly incremented) position; the number of malformed bytes may be determined by invoking the result object's {@link java.nio.charset.CoderResult#length() length} method. This case applies only if the {@linkplain #onMalformedInput malformed action} of this decoder is {@link java.nio.charset.CodingErrorAction#REPORT}; otherwise the malformed input will be ignored or replaced, as requested. </p></li> <li><p> An {@linkplain java.nio.charset.CoderResult#unmappableForLength unmappable-character} result indicates that an unmappable-character error has been detected. The bytes that decode the unmappable character begin at the input buffer's (possibly incremented) position; the number of such bytes may be determined by invoking the result object's {@link java.nio.charset.CoderResult#length() length} method. This case applies only if the {@linkplain #onUnmappableCharacter unmappable action} of this decoder is {@link java.nio.charset.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 decoding operation then care should be taken to preserve any bytes 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 undecoded input will be treated as being malformed. <p> This method works by invoking the {@link #decodeLoop decodeLoop} method, interpreting its results, handling error conditions, and reinvoking it as necessary. </p> @param {Object {ByteBuffer}} in The input byte buffer @param {Object {CharBuffer}} out The output character buffer @param {Boolean} endOfInput <tt>true</tt> if, and only if, the invoker can provide no additional input bytes beyond those in the given buffer @return {Object {java.nio.charset.CoderResult}} A coder-result object describing the reason for termination @throws IllegalStateException If a decoding 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 decoding operation @throws CoderMalfunctionError If an invocation of the decodeLoop method threw an unexpected exception */ decode : function( ) {}, /**Flushes this decoder. <p> Some decoders maintain internal state and may need to write some final characters 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()} characters 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 java.nio.charset.CoderResult#UNDERFLOW}. If there is insufficient room in the output buffer then it returns {@link java.nio.charset.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">decoding operation</a>. <p> If this decoder 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 {Object {CharBuffer}} out The output character buffer @return {Object {java.nio.charset.CoderResult}} A coder-result object, either {@link CoderResult#UNDERFLOW} or {@link CoderResult#OVERFLOW} @throws IllegalStateException If the previous step of the current decoding operation was an invocation neither of the {@link #flush flush} method nor of the three-argument {@link #decode(ByteBuffer,CharBuffer,boolean) decode} method with a value of <tt>true</tt> for the <tt>endOfInput</tt> parameter */ flush : function( ) {}, /**Resets this decoder, 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 {Object {java.nio.charset.CharsetDecoder}} This decoder */ reset : function( ) {}, /**Convenience method that decodes the remaining content of a single input byte buffer into a newly-allocated character buffer. <p> This method implements an entire <a href="#steps">decoding operation</a>; that is, it resets this decoder, then it decodes the bytes in the given byte buffer, and finally it flushes this decoder. This method should therefore not be invoked if a decoding operation is already in progress. </p> @param {Object {ByteBuffer}} in The input byte buffer @return {Object {java.nio.CharBuffer}} A newly-allocated character buffer containing the result of the decoding operation. The buffer's position will be zero and its limit will follow the last character written. @throws IllegalStateException If a decoding operation is already in progress @throws MalformedInputException If the byte sequence starting at the input buffer's current position is not legal for this charset and the current malformed-input action is {@link CodingErrorAction#REPORT} @throws UnmappableCharacterException If the byte sequence starting at the input buffer's current position cannot be mapped to an equivalent character sequence and the current unmappable-character action is {@link CodingErrorAction#REPORT} */ decode : function( ) {}, /**Tells whether or not this decoder implements an auto-detecting charset. <p> The default implementation of this method always returns <tt>false</tt>; it should be overridden by auto-detecting decoders to return <tt>true</tt>. </p> @return {Boolean} <tt>true</tt> if, and only if, this decoder implements an auto-detecting charset */ isAutoDetecting : function( ) {}, /**Tells whether or not this decoder has yet detected a charset <i>(optional operation)</i>. <p> If this decoder implements an auto-detecting charset then at a single point during a decoding operation this method may start returning <tt>true</tt> to indicate that a specific charset has been detected in the input byte sequence. Once this occurs, the {@link #detectedCharset detectedCharset} method may be invoked to retrieve the detected charset. <p> That this method returns <tt>false</tt> does not imply that no bytes have yet been decoded. Some auto-detecting decoders are capable of decoding some, or even all, of an input byte sequence without fixing on a particular charset. <p> The default implementation of this method always throws an {@link UnsupportedOperationException}; it should be overridden by auto-detecting decoders to return <tt>true</tt> once the input charset has been determined. </p> @return {Boolean} <tt>true</tt> if, and only if, this decoder has detected a specific charset @throws UnsupportedOperationException If this decoder does not implement an auto-detecting charset */ isCharsetDetected : function( ) {}, /**Retrieves the charset that was detected by this decoder <i>(optional operation)</i>. <p> If this decoder implements an auto-detecting charset then this method returns the actual charset once it has been detected. After that point, this method returns the same value for the duration of the current decoding operation. If not enough input bytes have yet been read to determine the actual charset then this method throws an {@link IllegalStateException}. <p> The default implementation of this method always throws an {@link UnsupportedOperationException}; it should be overridden by auto-detecting decoders to return the appropriate value. </p> @return {Object {java.nio.charset.Charset}} The charset detected by this auto-detecting decoder, or <tt>null</tt> if the charset has not yet been determined @throws IllegalStateException If insufficient bytes have been read to determine a charset @throws UnsupportedOperationException If this decoder does not implement an auto-detecting charset */ detectedCharset : function( ) {}, };