GZipTF

Compress a file using the gzip algorithm.

Description:

Compress a file using the gzip algorithm.

The target property is optional if the source file is of a type that implements Named. If the target is not set, the compressed data will be written to a file with the same name as the source file plus the extension .gz.

This task uses Java's GZIPOutputStream. It does not allow the compression level to be configured. Instead it always uses zlib's default level, which currently is 6 on a scale from 1 (fastest compression) to 9 (best compression).

Note: If another task created the file to compress, it may be easier to use a GZipNewWritableFileProxy directly with that task instead instead of using a separate GZip task for the compression.

Note 2: There is no task for decompressing gzip compressed files. Use a GZipReadableFile or a GZipReadableFileProxy instead.

Required properties

• source
• target

Properties

The buffer size of the GZIPOutputStream used by the task.

Setter method:

setBufferSize(int size)
parameters:

size – The buffer size, in bytes.

If this property is set to true, the source file will be deleted after compressing it. This requires that the source file is a Java File or an EntityFS EFile. If it is not, this task does not delete the file and logs a warning.

Setter method:

setDeleteSourceFile(boolean b)
parameters:

b – Should the source file be deleted?

The message that is logged to info level after the task has been successfully run.

Setter method:

setLogFooter(String s)
parameters:

s – The footer message.

Default value:

Empty (no footer message is logged.)

See also:

logHeader

The message that is logged to info level before the task is run.

Setter method:

setLogHeader(String s)
parameters:

s – The header message.

Default value:

A task class specific message.

See also:

logFooter

The overwrite strategy decides how the task will react if there already is an entity (file or directory) in a location where it wants to create a new entity.

If the strategy is to not overwrite existing entities, the task will fail when it cannot create the entities that it wants to create.

Non-empty directories are never overwritten, regardless of the chosen strategy.

Setter method:

setOverwrite(boolean b)

Setting this to a value of true means that the DoOverwriteAndLogWarning strategy is used. A value of false gives the DontOverwriteAndThrowException strategy.

parameters:

b – Should an existing entity be overwritten?

Setter method:

setOverwriteStrategy(OverwriteStrategy strat)

Set the overwrite strategy.

parameters:

strat – The overwrite strategy.

Default value:

DontOverwriteAndThrowException

See also:

target

This property is used to change the Report level for all task created by this task factory. The report level is changed for the thread running the task when the it is run, and is restored to its previous level when the it is done.

Setter method:

setReportLevel(Level l)

Set the report level

parameters:

l – The new report level.

The file to compress.

Setter method:

setSource(Object o)
parameters:

o –  The source file.
Interpreted by InterpretAsReadableFileStrategy.

The file that the compressed data should be put in.

Setter method:

setTarget(Object o)

Set the target.

parameters:

o – A target that can be interpreted as a writable file. If the target already exists, the overwriteStrategy property determines what will happen.
Interpreted by InterpretAsNewWritableFileStrategy.

See also:

overwriteStrategy

If trace logging is enabled for a task, it reports its configuration before it is run.

Trace logging may also be enabled globally for all tasks by calling TraceMode.setTraceMode(boolean).

Setter method:

setTraceLogging(boolean b)

Enable or disable trace logging.

parameters:

b – Enable trace logging?

Examples

Example 1

Compress the file f in the Directory dir to f.gz in the same directory.

Example 2

Put some text in the gzip compressed file f.gz.

* An EntityFS-aware task is implemented using EntityFS. This means that it uses the filter settings of DirectoryView:s and also that it often can work with other file system implementations than File-based, such as the RAM file system.