compact1, compact2, compact3

java.nio.charset

Class CharsetDecoder

java.lang.Object

java.nio.charset.CharsetDecoder

public abstract class CharsetDecoder
extends Object

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

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 decoding operation:

1. Reset the decoder via the reset method, unless it has not been used before;

2. Invoke the decode 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;

3. Invoke the decode method one final time, passing true for the endOfInput argument; and then

4. Invoke the flush method so that the decoder can flush any internal state to the output buffer.

Each invocation of the decode method will decode as many bytes as possible from the input buffer, writing the resulting characters to the output buffer. The 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 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.

There are two general types of decoding errors. If the input byte sequence is not legal for this charset then the input is considered malformed. If the input byte sequence is legal but cannot be mapped to a valid Unicode character then an unmappable character has been encountered.

How a decoding 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 string. The replacement has the initial value "\uFFFD"; 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