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new 709d099c [VFS-853] Fix FileListener on DelegateFileObject.
709d099c is described below
commit 709d099ce6bb98f1c781e18c9e211304188ce260
Author: Bernd Eckenfels <e...@apache.org>
AuthorDate: Mon May 27 17:25:57 2024 +0200
[VFS-853] Fix FileListener on DelegateFileObject.
This adds a new test JunctionTests#testEvent() which fails when
the fix is not present.
---
.../commons/vfs2/util/WeakRefFileListener.java | 15 ++++-
.../commons/vfs2/provider/test/JunctionTests.java | 77 ++++++++++++++++++++++
src/changes/changes.xml | 3 +
3 files changed, 93 insertions(+), 2 deletions(-)
diff --git
a/commons-vfs2/src/main/java/org/apache/commons/vfs2/util/WeakRefFileListener.java
b/commons-vfs2/src/main/java/org/apache/commons/vfs2/util/WeakRefFileListener.java
index 99e2303c..05c989f1 100644
---
a/commons-vfs2/src/main/java/org/apache/commons/vfs2/util/WeakRefFileListener.java
+++
b/commons-vfs2/src/main/java/org/apache/commons/vfs2/util/WeakRefFileListener.java
@@ -32,13 +32,24 @@ import org.apache.commons.vfs2.FileSystem;
public class WeakRefFileListener implements FileListener {
/**
- * Installs the {@code listener} at the given {@code file}.
+ * Install the {@code listener} at the given {@code file}.
+ * <p>
+ * This installs a wrapper with a weak reference, so the listener can
+ * be collected. The reference to the listener is removed when the
+ * first event can't be delivered.
+ * <p>
+ * Warning: you cannot remove the listener with
+ * {@code fs.removeListener(file, listener)} as you do'nt have the wrapper
+ * instance at hand.
+ * <p>
+ * Method is used by {@link
org.apache.commons.vfs2.provider.DelegateFileObject},
+ * as used for {@link org.apache.commons.vfs2.impl.VirtualFileSystem}.
*
* @param file The FileObject to listen on.
* @param listener The FileListener
*/
public static void installListener(final FileObject file, final
FileListener listener) {
- file.getFileSystem().addListener(file, new WeakRefFileListener(file,
new WeakRefFileListener(file, listener)));
+ file.getFileSystem().addListener(file, new WeakRefFileListener(file,
listener));
}
private final FileSystem fs;
diff --git
a/commons-vfs2/src/test/java/org/apache/commons/vfs2/provider/test/JunctionTests.java
b/commons-vfs2/src/test/java/org/apache/commons/vfs2/provider/test/JunctionTests.java
index 41bc76b9..9099b67c 100644
---
a/commons-vfs2/src/test/java/org/apache/commons/vfs2/provider/test/JunctionTests.java
+++
b/commons-vfs2/src/test/java/org/apache/commons/vfs2/provider/test/JunctionTests.java
@@ -22,9 +22,13 @@ import static
org.apache.commons.vfs2.VfsTestUtils.getTestDirectoryFile;
import java.io.File;
import org.apache.commons.vfs2.AbstractProviderTestCase;
+import org.apache.commons.vfs2.FileChangeEvent;
+import org.apache.commons.vfs2.FileListener;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystem;
import org.apache.commons.vfs2.FileSystemException;
+import org.apache.commons.vfs2.provider.DelegateFileObject;
+import org.apache.commons.vfs2.util.WeakRefFileListener;
import org.junit.Test;
/**
@@ -92,6 +96,52 @@ public class JunctionTests extends AbstractProviderTestCase {
}
}
+ /**
+ * Checks that change events from delegatedd files are fired.
+ */
+ public void testEvent() throws Exception {
+ // we use the VirtualFileSystem to check change event propagation of
DecoratedFileObject
+ final FileSystem fs =
getManager().createVirtualFileSystem("vfs://").getFileSystem();
+ final FileObject baseDir = getBaseDir().resolveFile("junctiontest");
+
+ // Add the junction
+ fs.addJunction("/a", baseDir);
+
+ // Make sure the file at the junction point and its ancestors exist
+ FileObject file = fs.resolveFile("/a/hardref.txt");
+ assertSame("VirtualFileSystem does not use DelegateFO anymore?",
file.getClass(), DelegateFileObject.class);
+
+ // Do with a hard reference listener
+ FileListener listener1 = new DebugFileListener();
+ file.getFileSystem().addListener(file, listener1);
+ FileObject real1 = baseDir.resolveFile("hardref.txt");
+ real1.createFile();
+ assertEquals("Strong Listener was not notified (create)", "Listener
false true false", listener1.toString());
+ real1.delete();
+ assertEquals("Strong Listener was not notified (delete)", "Listener
false true true", listener1.toString());
+
+ FileObject file2 = fs.resolveFile("/a/weakref.txt");
+ assertSame("VirtualFileSystem does not use DelegateFO anymore?",
file2.getClass(), DelegateFileObject.class);
+ // repeat with Weak reference listener
+ FileListener listener2 = new DebugFileListener();
+ // since we hold the listener2 reference it should not get GC
+ WeakRefFileListener.installListener(file2, listener2);
+
+ // force the WekRefFileListener reference to (not) clear
+ System.gc();
+ Thread.sleep(1000);
+ System.gc();
+ Thread.sleep(1000);
+ System.gc();
+ Thread.sleep(1000);
+ System.gc();
+ Thread.sleep(1000);
+
+ FileObject real2 = baseDir.resolveFile("weakref.txt");
+ real2.createFile();
+ assertEquals("Weak Listener was abandoned", "Listener false true
false", listener2.toString());
+ }
+
// Check that file @ junction point exists only when backing file exists
// Add 2 junctions with common parent
// Compare real and virtual files
@@ -99,3 +149,30 @@ public class JunctionTests extends AbstractProviderTestCase
{
// Remove junctions
}
+
+class DebugFileListener implements FileListener {
+ private boolean changed;
+ private boolean created;
+ private boolean deleted;
+
+ @Override
+ public void fileChanged(FileChangeEvent event) throws Exception {
+ changed = true;
+ }
+
+ @Override
+ public void fileCreated(FileChangeEvent event) throws Exception {
+ created = true;
+ }
+
+ @Override
+ public void fileDeleted(FileChangeEvent event) throws Exception {
+ deleted = true;
+ }
+
+ @Override
+ public String toString() {
+ return "Listener " + changed + " " + created + " " + deleted;
+ }
+} // class DebugListener
+
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 6e529c61..79932deb 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -47,6 +47,9 @@ The <action> type attribute can be add,update,fix,remove.
<body>
<release version="2.10.0" date="YYYY-MM-DD" description="Maintenance
release. Requires Java 8 or above.">
<!-- FIX -->
+ <action type="fix" issue="VFS-853" dev="ecki" due-to="Bernd Eckenfels">
+ Double wrapped weak FileListener can lose change notification with
DelegateFileObject.
+ </action>
<action type="fix" dev="ggregory" due-to="Seth Falco">
Replace package.html with package-info.java #206.
</action>
