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IN PROGRESS - issue INT-541: add optional Comparator argument to FileReadingMessageSource (to pass into the PriorityBlockingQueue constructor)

Browse Source 
http://jira.springframework.org/browse/INT-541

Added constructor argument and test.
This commit is contained in:
Iwein Fuld
2009-01-09 14:49:14 +00:00
parent 9d1403463b
commit 747050ab8c
2 changed files with 64 additions and 12 deletions
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37
org.springframework.integration.file/src/main/java/org/springframework/integration/file/FileReadingMessageSource.java
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@@ -19,6 +19,7 @@ package org.springframework.integration.file;
import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Queue;
@@ -28,6 +29,7 @@ import java.util.concurrent.PriorityBlockingQueue;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.io.Resource;
import org.springframework.integration.aggregator.Resequencer;
import org.springframework.integration.core.Message;
import org.springframework.integration.core.MessagingException;
import org.springframework.integration.message.GenericMessage;
@@ -35,9 +37,9 @@ import org.springframework.integration.message.MessageSource;
import org.springframework.util.Assert;
/**
* PollableSource that creates messages from a file system directory. To prevent
* messages for certain files, you may supply a {@link FileListFilter}. By
* default, an {@link AcceptOnceFileListFilter} is used. It ensures files are
* {@link MessageSource} that creates messages from a file system directory. To
* prevent messages for certain files, you may supply a {@link FileListFilter}.
* By default, an {@link AcceptOnceFileListFilter} is used. It ensures files are
* picked up only once from the directory.
* <p/>
* A common problem with reading files is that a file may be detected before it
@@ -48,6 +50,11 @@ import org.springframework.util.Assert;
* with the default {@link AcceptOnceFileListFilter} would allow for this. See
* {@link CompositeFileFilter} for a way to do this.
* <p/>
* A {@link Comparator} can be used to ensure internal ordering of the Files in
* a {@link PriorityBlockingQueue}. This does not provide the same guarantees as
* a {@link Resequencer}, but in cases where writing files and failure
* downstream are rare it might be sufficient.
* <p/>
* FileReadingMessageSource is fully thread-safe under concurrent receives and
* message delivery callbacks.
*
@@ -55,6 +62,8 @@ import org.springframework.util.Assert;
*/
public class FileReadingMessageSource implements MessageSource<File> {
private static final int INTERNAL_QUEUE_CAPACITY = 5;
private static final Log logger = LogFactory.getLog(FileReadingMessageSource.class);
private volatile File inputDirectory;
@@ -64,10 +73,28 @@ public class FileReadingMessageSource implements MessageSource<File> {
* {@link ConcurrentModificationException} in Java 5. There is no locking
* around the queue, so there is also no iteration.
*/
private final Queue<File> toBeReceived = new PriorityBlockingQueue<File>();
private final Queue<File> toBeReceived;
private volatile FileListFilter filter = new AcceptOnceFileListFilter();
/**
* Creates a FileReadingMessageSource with a naturally ordered queue.
*/
public FileReadingMessageSource() {
toBeReceived = new PriorityBlockingQueue<File>(INTERNAL_QUEUE_CAPACITY);
}
/**
* Creates a FileReadingMessageSource with a {@link PriorityBlockingQueue}
* ordered with the passed in {@link Comparator}
*
* No guarantees about file delivery order can be made under concurrent
* access.
*/
public FileReadingMessageSource(Comparator<File> receptionOrderComparator) {
toBeReceived = new PriorityBlockingQueue<File>(INTERNAL_QUEUE_CAPACITY, receptionOrderComparator);
}
public void setInputDirectory(Resource inputDirectory) {
Assert.notNull(inputDirectory, "inputDirectory cannot be null");
Assert.isTrue(inputDirectory.exists(), inputDirectory + " doesn't exist.");
@@ -87,7 +114,7 @@ public class FileReadingMessageSource implements MessageSource<File> {
* and duplication concerns. If multiple filters are required a
* {@link CompositeFileListFilter} can be used to group them together
* <p/>
* <b>Note that the supplied filter must be thread safe</b>.
* <b>Note that the supplied filter must be thread safe.</b>.
*/
public void setFilter(FileListFilter filter) {
Assert.notNull(filter, "'filter' should not be null");