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INT-984: added file locking and scanner documentation

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Iwein Fuld
2010-06-24 21:14:40 +00:00
parent 886835b01c
commit f4ed920d06
1 changed files with 29 additions and 0 deletions
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src/docbkx/file.xml
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@@ -100,6 +100,35 @@
you can use a <classname>CompositeFileListFilter</classname> to use any combination of filters, including a
pattern based filter to fit your particular needs.
</para>
<para>
When multiple processes are reading from the same directory it can be desirable to lock files to prevent
them from being picked up concurrently. To do this you can use a <interfacename>FileLocker</interfacename>.
There is a java.nio based implementation available out of the box, but it is also possible to implement your
own locking scheme. The nio locker can be injected as follows
<programlisting><![CDATA[ <file:inbound-channel-adapter id="filesIn"
directory="file:${input.directory}" prevent-duplicates="true">
<file:nio-locker/>
</file:inbound-channel-adapter>]]>
</programlisting>
A custom locker you can configure like this:
<programlisting><![CDATA[ <file:inbound-channel-adapter id="filesIn"
directory="file:${input.directory}" prevent-duplicates="true">
<file:locker ref="customLocker"/>
</file:inbound-channel-adapter>]]>
</programlisting>
</para>
<para>
When filtering and locking files is not enough it might be needed to control the way files are listed entirely. To
implement this type of requirement you can use an implementation of <interfacename>DirectoryScanner</interfacename>.
This scanner allows you to determine entirely what files are listed each poll. This is also the interface
that Spring Integration uses internally to wire FileListFilters FileLocker to the FileReadingMessageSource.
A custom DirectoryScanner can be injected into the &lt;file:inbound-channel-adapter/&gt; on the <code>scanner</code>
attribute.
<programlisting><![CDATA[ <file:inbound-channel-adapter id="filesIn"
directory="file:${input.directory}" prevent-duplicates="true" scanner="customDirectoryScanner"/>]]>
</programlisting>
This gives you full freedom to choose the ordering, listing and locking strategies.
</para>
</section>
<section id="file-writing">