CoderResult (Java 2 Platform SE v1.4.1) - JDK 5 Documentation v1.4.1, Java 2 SDK 英文文档

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Java^TM 2 Platform
Std. Ed. v1.4.1

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java.nio.charset
Class CoderResult

java.lang.Object
  |
  +--java.nio.charset.CoderResult

public class CoderResult
extends Object

A description of the result state of a coder.

A charset coder, that is, either a decoder or an encoder, consumes bytes (or characters) from an input buffer, translates them, and writes the resulting characters (or bytes) to an output buffer. A coding process terminates for one of four categories of reasons, which are described by instances of this class:

Underflow is reported when there is no more input to be processed, or there is insufficient input and additional input is required. This condition is represented by the unique result object UNDERFLOW, whose isUnderflow method returns true.
Overflow is reported when there is insufficient room remaining in the output buffer. This condition is represented by the unique result object OVERFLOW, whose isOverflow method returns true.
A malformed-input error is reported when a sequence of input units is not well-formed. Such errors are described by instances of this class whose isMalformed method returns true and whose length method returns the length of the malformed sequence. There is one unique instance of this class for all malformed-input errors of a given length.
An unmappable-character error is reported when a sequence of input units denotes a character that cannot be represented in the output charset. Such errors are described by instances of this class whose isUnmappable method returns true and whose length method returns the length of the input sequence denoting the unmappable character. There is one unique instance of this class for all unmappable-character errors of a given length.

For convenience, the isError method returns true for result objects that describe malformed-input and unmappable-character errors but false for those that describe underflow or overflow conditions.

Since:: 1.4

Field Summary

static CoderResult OVERFLOW
          Result object indicating overflow, meaning that there is insufficient room in the output buffer.

static CoderResult UNDERFLOW
          Result object indicating underflow, meaning that either the input buffer has been completely consumed or, if the input buffer is not yet empty, that additional input is required.

Method Summary

boolean isError()
          Tells whether or not this object describes an error condition.

boolean isMalformed()
          Tells whether or not this object describes a malformed-input error.

boolean isOverflow()
          Tells whether or not this object describes an overflow condition.

boolean isUnderflow()
          Tells whether or not this object describes an underflow condition.

boolean isUnmappable()
          Tells whether or not this object describes an unmappable-character error.

int length()
          Returns the length of the erroneous input described by this object  (optional operation).

static CoderResult malformedForLength(int length)
          Static factory method that returns the unique object describing a malformed-input error of the given length.

void throwException()
          Throws an exception appropriate to the result described by this object.

String toString()
          Returns a string describing this coder result.

static CoderResult unmappableForLength(int length)
          Static factory method that returns the unique result object describing an unmappable-character error of the given length.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

UNDERFLOW

public static final CoderResult UNDERFLOW

Result object indicating underflow, meaning that either the input buffer has been completely consumed or, if the input buffer is not yet empty, that additional input is required.

OVERFLOW

public static final CoderResult OVERFLOW

Result object indicating overflow, meaning that there is insufficient room in the output buffer.

Method Detail

toString

public String toString()

Returns a string describing this coder result.

Overrides:: toString in class Object

Returns:: A descriptive string

isUnderflow

public boolean isUnderflow()

Tells whether or not this object describes an underflow condition.

Returns:: true if, and only if, this object denotes underflow

isOverflow

public boolean isOverflow()

Tells whether or not this object describes an overflow condition.

Returns:: true if, and only if, this object denotes overflow

isError

public boolean isError()

Tells whether or not this object describes an error condition.

Returns:: true if, and only if, this object denotes either a malformed-input error or an unmappable-character error

isMalformed

public boolean isMalformed()

Tells whether or not this object describes a malformed-input error.

Returns:: true if, and only if, this object denotes a malformed-input error

isUnmappable

public boolean isUnmappable()

Tells whether or not this object describes an unmappable-character error.

Returns:: true if, and only if, this object denotes an unmappable-character error

length

public int length()

Returns the length of the erroneous input described by this object (optional operation).

Returns:: The length of the erroneous input, a positive integer
Throws:: UnsupportedOperationException - If this object does not describe an error condition, that is, if the isError does not return true

malformedForLength

public static CoderResult malformedForLength(int length)

Static factory method that returns the unique object describing a malformed-input error of the given length.

Returns:: The requested coder-result object

unmappableForLength

public static CoderResult unmappableForLength(int length)

Static factory method that returns the unique result object describing an unmappable-character error of the given length.

Returns:: The requested coder-result object

throwException

public void throwException()
                    throws CharacterCodingException

Throws an exception appropriate to the result described by this object.

Throws:: BufferUnderflowException - If this object is UNDERFLOW; BufferOverflowException - If this object is OVERFLOW; MalformedInputException - If this object represents a malformed-input error; the exception's length value will be that of this object; UnmappableCharacterException - If this object represents an unmappable-character error; the exceptions length value will be that of this object; CharacterCodingException