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Added in API level 1

FilterReader

public abstract class FilterReader
extends Reader

java.lang.Object
   ↳ java.io.Reader
     ↳ java.io.FilterReader
Known Direct Subclasses


Wraps an existing Reader and performs some transformation on the input data while it is being read. Transformations can be anything from a simple byte-wise filtering input data to an on-the-fly compression or decompression of the underlying reader. Readers that wrap another reader and provide some additional functionality on top of it usually inherit from this class.

See also:

Summary

Fields

protected Reader in

The target Reader which is being filtered.

Inherited fields

From class java.io.Reader

Protected constructors

FilterReader(Reader in)

Constructs a new FilterReader on the Reader in.

Public methods

void close()

Closes this reader.

void mark(int readlimit)

Sets a mark position in this reader.

boolean markSupported()

Indicates whether this reader supports mark() and reset().

int read()

Reads a single character from the filtered reader and returns it as an integer with the two higher-order bytes set to 0.

int read(char[] buffer, int offset, int count)

Reads up to count characters from the filtered reader and stores them in the byte array buffer starting at offset.

boolean ready()

Indicates whether this reader is ready to be read without blocking.

void reset()

Resets this reader's position to the last marked location.

long skip(long charCount)

Skips charCount characters in this reader.

Inherited methods

From class java.io.Reader
From class java.lang.Object
From interface java.lang.Readable
From interface java.io.Closeable
From interface java.lang.AutoCloseable

Fields

in

Added in API level 1
Reader in

The target Reader which is being filtered.

Protected constructors

FilterReader

Added in API level 1
FilterReader (Reader in)

Constructs a new FilterReader on the Reader in.

Parameters
in Reader: The non-null Reader to filter reads on.

Public methods

close

Added in API level 1
void close ()

Closes this reader. This implementation closes the filtered reader.

Throws
IOException if an error occurs while closing this reader.

mark

Added in API level 1
void mark (int readlimit)

Sets a mark position in this reader. The parameter readlimit indicates how many bytes can be read before the mark is invalidated. Sending reset() will reposition this reader back to the marked position, provided that readlimit has not been surpassed.

This implementation sets a mark in the filtered reader.

Parameters
readlimit int: the number of bytes that can be read from this reader before the mark is invalidated.
Throws
IOException if an error occurs while marking this reader.

See also:

markSupported

Added in API level 1
boolean markSupported ()

Indicates whether this reader supports mark() and reset(). This implementation returns whether the filtered reader supports marking.

Returns
boolean true if mark() and reset() are supported by the filtered reader, false otherwise.

See also:

read

Added in API level 1
int read ()

Reads a single character from the filtered reader and returns it as an integer with the two higher-order bytes set to 0. Returns -1 if the end of the filtered reader has been reached.

Returns
int The character read or -1 if the end of the filtered reader has been reached.
Throws
IOException if an error occurs while reading from this reader.

read

Added in API level 1
int read (char[] buffer, 
                int offset, 
                int count)

Reads up to count characters from the filtered reader and stores them in the byte array buffer starting at offset. Returns the number of characters actually read or -1 if no characters were read and the end of the filtered reader was encountered.

Parameters
buffer char
offset int
count int
Returns
int
Throws
IOException if an error occurs while reading from this reader.

ready

Added in API level 1
boolean ready ()

Indicates whether this reader is ready to be read without blocking. If the result is true, the next read() will not block. If the result is false, this reader may or may not block when read() is sent.

Returns
boolean true if this reader will not block when read() is called, false if unknown or blocking will occur.
Throws
IOException if the reader is closed or some other I/O error occurs.

reset

Added in API level 1
void reset ()

Resets this reader's position to the last marked location. Invocations of read() and skip() will occur from this new location. If this reader was not marked, the behavior depends on the implementation of reset() in the Reader subclass that is filtered by this reader. The default behavior for Reader is to throw an IOException.

Throws
IOException if a problem occurred or the filtered reader does not support mark() and reset().

See also:

skip

Added in API level 1
long skip (long charCount)

Skips charCount characters in this reader. Subsequent calls to read will not return these characters unless reset is used. The default implementation is to skip characters in the filtered reader.

Parameters
charCount long
Returns
long the number of characters actually skipped.
Throws
IOException if the filtered reader is closed or some other I/O error occurs.

See also:

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