CharsetDecoder Class

Definition

[Android.Runtime.Register("java/nio/charset/CharsetDecoder", DoNotGenerateAcw=true)]
public abstract class CharsetDecoder : Java.Lang.Object

[<Android.Runtime.Register("java/nio/charset/CharsetDecoder", DoNotGenerateAcw=true)>]
type CharsetDecoder = class
    inherit Object

Inheritance

Object

Object

CharsetDecoder

Attributes

RegisterAttribute

Remarks

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

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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:

<ol>

<li>

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

</li>

<li>

Invoke the #decode 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;

</li>

<li>

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

</li>

<li>

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

</li>

</ol>

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

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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.

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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 CodingErrorAction#IGNORE ignore the erroneous input, CodingErrorAction#REPORT report the error to the invoker via the returned CoderResult object, or CodingErrorAction#REPLACE 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(java.lang.String) replaceWith method.

The default action for malformed-input and unmappable-character errors is to CodingErrorAction#REPORT report them. The malformed-input error action may be changed via the #onMalformedInput(CodingErrorAction) onMalformedInput method; the unmappable-character action may be changed via the #onUnmappableCharacter(CodingErrorAction) onUnmappableCharacter method.

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 #decodeLoop decodeLoop method, which encapsulates the basic decoding loop. A subclass that maintains internal state should, additionally, override the #implFlush implFlush and #implReset implReset methods.

Instances of this class are not safe for use by multiple concurrent threads.

Added in 1.4.

Java documentation for java.nio.charset.CharsetDecoder.

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

Constructors

Properties

Methods

Explicit Interface Implementations

Extension Methods

Applies to