org.apache.tools.ant.filters
Class HeadFilter

java.lang.Object
  |
  +--java.io.Reader
        |
        +--java.io.FilterReader
              |
              +--org.apache.tools.ant.filters.BaseFilterReader
                    |
                    +--org.apache.tools.ant.filters.BaseParamFilterReader
                          |
                          +--org.apache.tools.ant.filters.HeadFilter

All Implemented Interfaces:

ChainableReader, Parameterizable

public final class HeadFilter

extends BaseParamFilterReader

implements ChainableReader

Reads the first n lines of a stream. (Default is first 10 lines.)

Example:

<headfilter lines="3"/>

Or:

<filterreader classname="org.apache.tools.ant.filters.HeadFilter">
    <param name="lines" value="3"/>
 </filterreader>

Field Summary

Fields inherited from class java.io.FilterReader

in

Fields inherited from class java.io.Reader

lock

Constructor Summary

HeadFilter()
Constructor for "dummy" instances.

HeadFilter(java.io.Reader in)
Creates a new filtered reader.

Method Summary

java.io.Reader	chain(java.io.Reader rdr) Creates a new HeadFilter using the passed in Reader for instantiation.
int	read() Returns the next character in the filtered stream.
void	setLines(long lines) Sets the number of lines to be returned in the filtered stream.
void	setSkip(long skip) Sets the number of lines to be skipped in the filtered stream.

Methods inherited from class org.apache.tools.ant.filters.BaseParamFilterReader

getParameters, setParameters

Methods inherited from class org.apache.tools.ant.filters.BaseFilterReader

getInitialized, getProject, read, readFully, readLine, setInitialized, setProject, skip

Methods inherited from class java.io.FilterReader

close, mark, markSupported, ready, reset

Methods inherited from class java.io.Reader

read

Methods inherited from class java.lang.Object

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

Constructor Detail

HeadFilter

public HeadFilter()

Constructor for "dummy" instances.

See Also:

BaseFilterReader.BaseFilterReader()

HeadFilter

public HeadFilter(java.io.Reader in)

Creates a new filtered reader.

Parameters:

in - A Reader object providing the underlying stream. Must not be null.

Method Detail

read

public final int read()
               throws java.io.IOException

Returns the next character in the filtered stream. If the desired number of lines have already been read, the resulting stream is effectively at an end. Otherwise, the next character from the underlying stream is read and returned.

Overrides:

read in class java.io.FilterReader

Returns:

the next character in the resulting stream, or -1 if the end of the resulting stream has been reached

Throws:

java.io.IOException - if the underlying stream throws an IOException during reading

setLines

public final void setLines(long lines)

Sets the number of lines to be returned in the filtered stream.

Parameters:

lines - the number of lines to be returned in the filtered stream

setSkip

public final void setSkip(long skip)

Sets the number of lines to be skipped in the filtered stream.

Parameters:

skip - the number of lines to be skipped in the filtered stream

chain

public final java.io.Reader chain(java.io.Reader rdr)

Creates a new HeadFilter using the passed in Reader for instantiation.

Specified by:

chain in interface ChainableReader

Parameters:

rdr - A Reader object providing the underlying stream. Must not be null.

Returns:

a new filter based on this configuration, but filtering the specified reader