org.apache.tools.ant.taskdefs.optional.unix
Class Symlink

java.lang.Object
  org.apache.tools.ant.ProjectComponent
      org.apache.tools.ant.Task
          org.apache.tools.ant.dispatch.DispatchTask
              org.apache.tools.ant.taskdefs.optional.unix.Symlink

All Implemented Interfaces:

java.lang.Cloneable, Dispatchable

public class Symlink
extends DispatchTask

Creates, Deletes, Records and Restores Symlinks.

This task performs several related operations. In the most trivial and default usage, it creates a link specified in the link attribute to a resource specified in the resource attribute. The second usage of this task is to traverse a directory structure specified by a fileset, and write a properties file in each included directory describing the links found in that directory. The third usage is to traverse a directory structure specified by a fileset, looking for properties files (also specified as included in the fileset) and recreate the links that have been previously recorded for each directory. Finally, it can be used to remove a symlink without deleting the associated resource.

Usage examples:

Make a link named "foo" to a resource named "bar.foo" in subdir:

 <symlink link="${dir.top}/foo" resource="${dir.top}/subdir/bar.foo"/>
 

Record all links in subdir and its descendants in files named "dir.links":

 <symlink action="record" linkfilename="dir.links">
    <fileset dir="${dir.top}" includes="subdir/**" />
 </symlink>
 

Recreate the links recorded in the previous example:

 <symlink action="recreate">
    <fileset dir="${dir.top}" includes="subdir/**/dir.links" />
 </symlink>
 

Delete a link named "foo" to a resource named "bar.foo" in subdir:

 <symlink action="delete" link="${dir.top}/foo"/>
 

LIMITATIONS: Because Java has no direct support for handling symlinks this task divines them by comparing canonical and absolute paths. On non-unix systems this may cause false positives. Furthermore, any operating system on which the command ln -s link resource is not a valid command on the command line will not be able to use action="delete", action="single" or action="recreate", but action="record" should still work. Finally, the lack of support for symlinks in Java means that all links are recorded as links to the canonical resource name. Therefore the link: link --> subdir/dir/../foo.bar will be recorded as link=subdir/foo.bar and restored as link --> subdir/foo.bar.

Field Summary

Fields inherited from class org.apache.tools.ant.Task

target, taskName, taskType, wrapper

Fields inherited from class org.apache.tools.ant.ProjectComponent

description, location, project

Constructor Summary

Symlink()

Method Summary

void	addFileset(FileSet set) Add a fileset to this task.
void	delete() Delete a symlink.
static void	deleteSymlink(java.io.File linkfil) Deprecated. use org.apache.tools.ant.util.SymbolicLinkUtils#deleteSymbolicLink instead
static void	deleteSymlink(java.lang.String path) Deprecated. use org.apache.tools.ant.util.SymbolicLinkUtils#deleteSymbolicLink instead
void	execute() The standard method for executing any task.
void	init() Initialize the task.
void	record() Record symlinks.
void	recreate() Restore symlinks.
void	setAction(java.lang.String action) Set the action to be performed.
void	setFailOnError(boolean foe) Set failonerror mode.
void	setLink(java.lang.String lnk) Set the name of the link.
void	setLinkfilename(java.lang.String lf) Set the name of the file to which links will be written.
void	setOverwrite(boolean owrite) Set overwrite mode.
void	setResource(java.lang.String src) Set the name of the resource to which a link should be created.
void	single() Create a symlink.

Methods inherited from class org.apache.tools.ant.dispatch.DispatchTask

getAction, getActionParameterName

Methods inherited from class org.apache.tools.ant.Task

bindToOwner, getOwningTarget, getRuntimeConfigurableWrapper, getTaskName, getTaskType, getWrapper, handleErrorFlush, handleErrorOutput, handleFlush, handleInput, handleOutput, isInvalid, log, log, log, log, maybeConfigure, perform, reconfigure, setOwningTarget, setRuntimeConfigurableWrapper, setTaskName, setTaskType

Methods inherited from class org.apache.tools.ant.ProjectComponent

clone, getDescription, getLocation, getProject, setDescription, setLocation, setProject

Methods inherited from class java.lang.Object

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

Constructor Detail

Symlink

public Symlink()

Method Detail

init

public void init()
          throws BuildException

Initialize the task.

Overrides:

init in class Task

Throws:

BuildException - on error.

execute

public void execute()
             throws BuildException

The standard method for executing any task.

Overrides:

execute in class Task

Throws:

BuildException - on error.

single

public void single()
            throws BuildException

Create a symlink.

Throws:

BuildException - on error.

Since:

Ant 1.7

delete

public void delete()
            throws BuildException

Delete a symlink.

Throws:

BuildException - on error.

Since:

Ant 1.7

recreate

public void recreate()
              throws BuildException

Restore symlinks.

Throws:

BuildException - on error.

Since:

Ant 1.7

record

public void record()
            throws BuildException

Record symlinks.

Throws:

BuildException - on error.

Since:

Ant 1.7

setOverwrite

public void setOverwrite(boolean owrite)

Set overwrite mode. If set to false (default) the task will not overwrite existing links, and may stop the build if a link already exists depending on the setting of failonerror.

Parameters:

owrite - If true overwrite existing links.

setFailOnError

public void setFailOnError(boolean foe)

Set failonerror mode. If set to true (default) the entire build fails upon error; otherwise the error is logged and the build will continue.

Parameters:

foe - If true throw BuildException on error, else log it.

setAction

public void setAction(java.lang.String action)

Set the action to be performed. May be "single", "delete", "recreate" or "record".

Overrides:

setAction in class DispatchTask

Parameters:

action - The action to perform.

setLink

public void setLink(java.lang.String lnk)

Set the name of the link. Used when action = "single".

Parameters:

lnk - The name for the link.

setResource

public void setResource(java.lang.String src)

Set the name of the resource to which a link should be created. Used when action = "single".

Parameters:

src - The resource to be linked.

setLinkfilename

public void setLinkfilename(java.lang.String lf)

Set the name of the file to which links will be written. Used when action = "record".

Parameters:

lf - The name of the file to write links to.

addFileset

public void addFileset(FileSet set)

Add a fileset to this task.

Parameters:

set - The fileset to add.

deleteSymlink

public static void deleteSymlink(java.lang.String path)
                          throws java.io.IOException,
                                 java.io.FileNotFoundException

Deprecated. use org.apache.tools.ant.util.SymbolicLinkUtils#deleteSymbolicLink instead

Delete a symlink (without deleting the associated resource).

This is a convenience method that simply invokes deleteSymlink(java.io.File).

Parameters:

path - A string containing the path of the symlink to delete.

Throws:

java.io.FileNotFoundException - When the path results in a File that doesn't exist.

java.io.IOException - If calls to File.rename or File.delete fail.

deleteSymlink

public static void deleteSymlink(java.io.File linkfil)
                          throws java.io.IOException

Deprecated. use org.apache.tools.ant.util.SymbolicLinkUtils#deleteSymbolicLink instead

Delete a symlink (without deleting the associated resource).

This is a utility method that removes a unix symlink without removing the resource that the symlink points to. If it is accidentally invoked on a real file, the real file will not be harmed.

This method works by getting the canonical path of the link, using the canonical path to rename the resource (breaking the link) and then deleting the link. The resource is then returned to its original name inside a finally block to ensure that the resource is unharmed even in the event of an exception.

Since Ant 1.8.0 this method will try to delete the File object if it reports it wouldn't exist (as symlinks pointing nowhere usually do). Prior version would throw a FileNotFoundException in that case.

Parameters:

linkfil - A File object of the symlink to delete.

Throws:

java.io.IOException - If calls to File.rename, File.delete or File.getCanonicalPath fail.