# filters/HeadFilter.php

## \HeadFilter
jump to top

Package: phing\filters

Reads the first <code>n</code> lines of a stream.

(Default is first 10 lines.)

<

p> Example:

Or:

Implements
  \ChainableReader
Parent(s)
  \BaseParamFilterReader < \BaseFilterReader < \FilterReader < \Reader
See
  \FilterReader
Access
  public
Author
  Yannick Lecaillez
Author
  hans lellelid, hans@velum.net
Copyright
  © 2003 seasonfive. All rights reserved
Version
  $Revision: 526 $ $Date: 2009-08-11 14:11:17 +0200 (Tue, 11 Aug 2009) $

### Constants

`LINES_KEY = "lines"`

Parameter name for the number of lines to be returned.

### Properties

`integer $_lines= '10'`

Number of lines to be returned in the filtered stream.

Default value `10` Details

Type
  integer

`integer $_linesRead= '0'`

Number of lines currently read in.

Default value `0` Details

Type
  integer

`$_parameters= 'array()'`
inherited

The passed in parameter array.

Inherited from: \BaseParamFilterReader::$$_parameters
Default value `array()`Details

Type
  n/a
Inherited_from
  \BaseParamFilterReader::$$_parameters

`$initialized= 'false'`
inherited

Have the parameters passed been interpreted?

Inherited from: \BaseFilterReader::$$initialized\BaseParamFilterReader::$$initialized
Default value `false` Details

Type
  n/a
Inherited_from
  \BaseFilterReader::$$initialized
Inherited_from
  \BaseParamFilterReader::$$initialized

`$project= 'null'`
inherited

The Phing project this filter is part of.

Inherited from: \BaseFilterReader::$$project\BaseParamFilterReader::$$project
Default value `null` Details

Type
  n/a
Inherited_from
  \BaseFilterReader::$$project
Inherited_from
  \BaseParamFilterReader::$$project

### Methods

`__construct( \Reader $in = null ) : void`
inherited

Constructor used by Phing's introspection mechanism.

Inherited from: \BaseFilterReader::__construct()\BaseParamFilterReader::__construct()

The original filter reader is only used for chaining purposes, never for filtering purposes (and indeed it would be useless for filtering purposes, as it has no real data to filter). ChainedReaderHelper uses this placeholder instance to create a chain of real filters.

Parameters

Name | Type | Description
--- | --- | ---
$in | \Reader |

`_initialize( ) : void`

Scans the parameters list for the "lines" parameter and uses it to set the number of lines to be returned in the filtered stream.

`chain( object $reader ) : object`

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

Parameters

Name | Type | Description
--- | --- | ---
$reader | object | A Reader object providing the underlying stream. Must not be `null`.

Returns

Type | Description
--- | ---
object | A new filter based on this configuration, but filtering the specified reader.

`close( ) : void`
inherited

Inherited from: FilterReader::close()\BaseFilterReader::close()\BaseParamFilterReader::close()
`eof( ) : boolean`
inherited

Returns whether the end of file has been reached with input stream.

Inherited from: \BaseFilterReader::eof()\BaseParamFilterReader::eof()
Returns

Type | Description
--- | ---
boolean |

`getInitialized( ) : boolean`
inherited

Returns the initialized status.

Inherited from: \BaseFilterReader::getInitialized()\BaseParamFilterReader::getInitialized()
Returns

Type | Description
--- | ---
boolean | whether or not the filter is initialized

`getLines( ) : integer`

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

Returns

Type | Description
--- | ---
integer | The number of lines to be returned in the filtered stream.

`getParameters( ) : void`
inherited

Inherited from: \BaseParamFilterReader::getParameters()
`getProject( ) : object`
inherited

Returns the project this filter is part of.

Inherited from: \BaseFilterReader::getProject()\BaseParamFilterReader::getProject()
Returns

Type | Description
--- | ---
object | The project this filter is part of

`getResource( ) : void`
inherited

Inherited from: FilterReader::getResource()\BaseFilterReader::getResource()\BaseParamFilterReader::getResource()
`log( string $msg, int $level = Project::MSG_INFO ) : void`
inherited

Convenience method to support logging in filters.

Inherited from: \BaseFilterReader::log()\BaseParamFilterReader::log()
Parameters

Name | Type | Description
--- | --- | ---
$msg | string | Message to log.
$level | int | Priority level.

`mark( ) : void`
inherited

Inherited from: Reader::mark()\BaseFilterReader::mark()\BaseParamFilterReader::mark()
`markSupported( ) : void`
inherited

Inherited from: Reader::markSupported()\BaseFilterReader::markSupported()\BaseParamFilterReader::markSupported()
`read( \off $len = null ) : \the`

Returns first n lines of stream.

Parameters

Name | Type | Description
--- | --- | ---
$len | \off | Offset at which to start storing characters.

Returns

Type | Description
--- | ---
\the | resulting stream, or -1 if the end of the resulting stream has been reached

Throws

Exception | Description
--- | ---
\IOException | If an I/O error occurs

Details

Exception
  IOException if the underlying stream throws an IOException during reading

`readLine( ) : \the`
inherited

Reads a line of text ending with '\n' (or until the end of the stream).

Inherited from: \BaseFilterReader::readLine()\BaseParamFilterReader::readLine()

The returned String retains the '\n'.

Returns

Type | Description
--- | ---
\the | line read, or <code>null</code> if the end of the stream has already been reached

Throws

Exception | Description
--- | ---
\IOException | if the underlying reader throws one during reading

`ready( ) : void`
inherited

Inherited from: Reader::ready()\BaseFilterReader::ready()\BaseParamFilterReader::ready()
`reset( ) : void`
inherited

Inherited from: FilterReader::reset()\BaseFilterReader::reset()\BaseParamFilterReader::reset()
`setInitialized( boolean $initialized ) : void`
inherited

Sets the initialized status.

Inherited from: \BaseFilterReader::setInitialized()\BaseParamFilterReader::setInitialized()
Parameters

Name | Type | Description
--- | --- | ---
$initialized | boolean | Whether or not the filter is initialized.

`setLines( integer $lines ) : void`

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

Parameters

Name | Type | Description
--- | --- | ---
$lines | integer | the number of lines to be returned in the filtered stream.

`setParameters( $parameters ) : void`
inherited

Inherited from: \BaseParamFilterReader::setParameters()
Parameters

Name | Type | Description
--- | --- | ---
$parameters |  |

`setProject( object $project ) : void`
inherited

Sets the project to work with.

Inherited from: \BaseFilterReader::setProject()\BaseParamFilterReader::setProject()
Parameters

Name | Type | Description
--- | --- | ---
$project | object | The project this filter is part of. Should not be `null`.

`setReader( ) : void`
inherited

Inherited from: FilterReader::setReader()\BaseFilterReader::setReader()\BaseParamFilterReader::setReader()
`skip( ) : void`
inherited

Inherited from: FilterReader::skip()\BaseFilterReader::skip()\BaseParamFilterReader::skip()
Documentation was generated by DocBlox 0.17.1.