org.oddjob.io

Class FileWatchService

java.lang.Object

org.oddjob.io.FileWatchService

All Implemented Interfaces:

Outbound<java.nio.file.Path>, Service, FileWatch, Stoppable

public class FileWatchService
extends java.lang.Object
implements FileWatch, Service, Outbound<java.nio.file.Path>

Description

Provide a service for subscribers to watch a file system for Files existing, being created or being modified.

If the file is created during subscription the consumer may receive a notification for the same file twice. Once the subscription has succeeded a consumer should receive every creation and modification happening to the file.

If this service is stopped no notification is sent to consumers. Consumers must use the state of this service to know that it has stopped.

Consumers will receive creation and modification events on a different thread to the initial event if the file exists.

Implementation Note: This facility is still a work in progress. Requiring this service in a configuration is messy. In future releases this service should be hidden from users.

Example

Trigger when two files arrive.

<oddjob>
    <job>
        <sequential>
            <jobs>
                <mkdir dir="${some.dir}/etc" name="Create Test Dir"/>
                <file-watch id="file-watch" kinds="ENTRY_CREATE"/>
                <events:when id="both-files" name="When Both Files" xmlns:events="oddjob:events">
                    <jobs>
                        <events:list eventOperator="ALL">
                            <of>
                                <events:watch name="Watch File 1">
                                    <eventSource>
                                        <events:file>
                                            <fileWatch>
                                                <value value="${file-watch}"/>
                                            </fileWatch>
                                            <file>
                                                <value value="${some.dir}/file1.txt"/>
                                            </file>
                                        </events:file>
                                    </eventSource>
                                </events:watch>
                                <events:watch name="Watch File 2">
                                    <eventSource>
                                        <events:file>
                                            <fileWatch>
                                                <value value="${file-watch}"/>
                                            </fileWatch>
                                            <file>
                                                <value value="${some.dir}/file2.txt"/>
                                            </file>
                                        </events:file>
                                    </eventSource>
                                </events:watch>
                            </of>
                        </events:list>
                        <echo id="task">
                            ${both-files.trigger.ofs}
                        </echo>
                    </jobs>
                </events:when>
                <folder>
                    <jobs>
                        <copy id="createFile1" name="Create File 1" to="${some.dir}/file1.txt">
                            <input>
                                <buffer>
                                    Test1
                                </buffer>
                            </input>
                        </copy>
                        <copy id="createFile2" name="Create File 2" to="${some.dir}/file2.txt">
                            <input>
                                <buffer>
                                    Test2
                                </buffer>
                            </input>
                        </copy>
                        <delete name="Delete All Test Files">
                            <files>
                                <files files="${some.dir}/*"/>
                            </files>
                        </delete>
                    </jobs>
                </folder>
            </jobs>
        </sequential>
    </job>
</oddjob>

See Also:

FileWatchEventSource

Author:

rob

Constructor Summary

Constructors

Constructor and Description
FileWatchService()

Method Summary

Modifier and Type	Method and Description
java.lang.String	getFilter()
java.lang.String	getKinds()
java.lang.String	getName()
int	getNumberOfConsumers()
java.util.List<java.nio.file.Path>	getPaths()
java.util.function.Consumer<? super java.nio.file.Path>	getTo()
void	setFilter(java.lang.String filter)
void	setKinds(java.lang.String kinds)
void	setName(java.lang.String name)
void	setPaths(java.util.List<java.nio.file.Path> paths)
void	setTo(java.util.function.Consumer<? super java.nio.file.Path> to) Set the out bound destination.
void	start() Start the service.
void	stop() Stop executing.
Restore	subscribe(java.nio.file.Path path, java.util.function.Consumer<? super InstantEvent<java.nio.file.Path>> consumer) Subscribe to notifications for the existence or modifications in the file.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

FileWatchService

public FileWatchService()

Method Detail

start

public void start()

Description copied from interface: Service

Start the service.

Specified by:

start in interface Service

stop

public void stop()

Description copied from interface: Stoppable

Stop executing. This method should not return until the Stoppable has actually stopped.

Specified by:

stop in interface Stoppable

subscribe

public Restore subscribe(java.nio.file.Path path,
                         java.util.function.Consumer<? super InstantEvent<java.nio.file.Path>> consumer)

Description copied from interface: FileWatch

Subscribe to notifications for the existence or modifications in the file.

If the file exists already the consumer will be notified before this method returns. If the file is created during the call to this method then the consumer may receive a notification for the same file twice. A consumer could use the modified date to remove duplicated but then may miss file modifications that happen close together. The documentation for implementations should adequately explain such behaviours.

Specified by:

subscribe in interface FileWatch

Parameters:

path - The path of the file to watch. Must not be null.

Returns:

Something that will close resources.

setFilter

public void setFilter(java.lang.String filter)

getFilter

public java.lang.String getFilter()

getNumberOfConsumers

public int getNumberOfConsumers()

getName

public java.lang.String getName()

setName

public void setName(java.lang.String name)

getKinds

public java.lang.String getKinds()

setKinds

public void setKinds(java.lang.String kinds)

getPaths

public java.util.List<java.nio.file.Path> getPaths()

setPaths

public void setPaths(java.util.List<java.nio.file.Path> paths)

getTo

public java.util.function.Consumer<? super java.nio.file.Path> getTo()

setTo

public void setTo(java.util.function.Consumer<? super java.nio.file.Path> to)

Description copied from interface: Outbound

Set the out bound destination.

Specified by:

setTo in interface Outbound<java.nio.file.Path>

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object