Author: rgoers
Date: Tue Nov 23 02:27:44 2010
New Revision: 1037973
URL: http://svn.apache.org/viewvc?rev=1037973&view=rev
Log:
Replace synchronization with locking and/or concurrent objects. Add
putFileIfAbsent method to allow callers to safely add to the cache
Modified:
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/FilesCache.java
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/DefaultFilesCache.java
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/LRUFilesCache.java
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/NullFilesCache.java
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/SoftRefFilesCache.java
Modified:
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/FilesCache.java
URL:
http://svn.apache.org/viewvc/commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/FilesCache.java?rev=1037973&r1=1037972&r2=1037973&view=diff
==============================================================================
---
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/FilesCache.java
(original)
+++
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/FilesCache.java
Tue Nov 23 02:27:44 2010
@@ -18,7 +18,7 @@ package org.apache.commons.vfs2;
/**
- * The fileCache interface.
+ * The fileCache interface. Implementations of this interface are expected to
be thread safe.
*
* @author <a href="http://commons.apache.org/vfs/team-list.html";>Commons VFS
team</a>
* @version $Revision$ $Date$
@@ -33,6 +33,14 @@ public interface FilesCache
void putFile(final FileObject file);
/**
+ * add a fileobject to the cache if it isn't already present.
+ *
+ * @param file the file
+ * @return true if the file was stored, false otherwise.
+ */
+ boolean putFileIfAbsent(final FileObject file);
+
+ /**
* retrieve a file from the cache by its name.
*
* @param filesystem The FileSystem.
Modified:
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/DefaultFilesCache.java
URL:
http://svn.apache.org/viewvc/commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/DefaultFilesCache.java?rev=1037973&r1=1037972&r2=1037973&view=diff
==============================================================================
---
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/DefaultFilesCache.java
(original)
+++
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/DefaultFilesCache.java
Tue Nov 23 02:27:44 2010
@@ -45,6 +45,12 @@ public class DefaultFilesCache extends A
files.put(file.getName(), file);
}
+ public boolean putFileIfAbsent(final FileObject file)
+ {
+ ConcurrentMap<FileName, FileObject> files =
getOrCreateFilesystemCache(file.getFileSystem());
+ return files.putIfAbsent(file.getName(), file) == null;
+ }
+
public FileObject getFile(final FileSystem filesystem, final FileName name)
{
Map<FileName, FileObject> files =
getOrCreateFilesystemCache(filesystem);
Modified:
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/LRUFilesCache.java
URL:
http://svn.apache.org/viewvc/commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/LRUFilesCache.java?rev=1037973&r1=1037972&r2=1037973&view=diff
==============================================================================
---
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/LRUFilesCache.java
(original)
+++
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/LRUFilesCache.java
Tue Nov 23 02:27:44 2010
@@ -16,8 +16,12 @@
*/
package org.apache.commons.vfs2.cache;
-import java.util.HashMap;
import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.apache.commons.collections.map.AbstractLinkedMap;
import org.apache.commons.collections.map.LRUMap;
@@ -47,12 +51,16 @@ public class LRUFilesCache extends Abstr
private final Log log = LogFactory.getLog(LRUFilesCache.class);
/** The FileSystem cache */
- private final Map<FileSystem, Map<FileName, FileObject>> filesystemCache =
- new HashMap<FileSystem, Map<FileName, FileObject>>(10);
+ private final ConcurrentMap<FileSystem, Map<FileName, FileObject>>
filesystemCache =
+ new ConcurrentHashMap<FileSystem, Map<FileName, FileObject>>(10);
/** The size of the cache */
private final int lruSize;
+ private ReadWriteLock rwLock = new ReentrantReadWriteLock();
+ private Lock readLock = rwLock.readLock();
+ private Lock writeLock = rwLock.writeLock();
+
/**
* The file cache
*/
@@ -132,40 +140,81 @@ public class LRUFilesCache extends Abstr
public void putFile(final FileObject file)
{
- synchronized (this)
- {
- Map<FileName, FileObject> files =
getOrCreateFilesystemCache(file.getFileSystem());
+ Map<FileName, FileObject> files =
getOrCreateFilesystemCache(file.getFileSystem());
+ writeLock.lock();
+ try
+ {
// System.err.println(">>> " + files.size() + " put:" +
file.toString());
files.put(file.getName(), file);
}
+ finally
+ {
+ writeLock.unlock();
+ }
}
- public FileObject getFile(final FileSystem filesystem, final FileName name)
+
+ public boolean putFileIfAbsent(final FileObject file)
{
- synchronized (this)
+ Map<FileName, FileObject> files =
getOrCreateFilesystemCache(file.getFileSystem());
+
+ writeLock.lock();
+ try
{
- Map<FileName, FileObject> files =
getOrCreateFilesystemCache(filesystem);
+ FileName name = file.getName();
+ // System.err.println(">>> " + files.size() + " put:" +
file.toString());
+ if (files.containsKey(name))
+ {
+ return false;
+ }
+
+ files.put(name, file);
+ return true;
+ }
+ finally
+ {
+ writeLock.unlock();
+ }
+ }
+
+ public FileObject getFile(final FileSystem filesystem, final FileName name)
+ {
+ Map<FileName, FileObject> files =
getOrCreateFilesystemCache(filesystem);
+
+ readLock.lock();
+ try
+ {
// FileObject fo = (FileObject) files.get(name);
// System.err.println(">>> " + files.size() + " get:" +
name.toString() + " " + fo);
return files.get(name);
}
+ finally
+ {
+ readLock.unlock();
+ }
}
public void clear(final FileSystem filesystem)
{
- synchronized (this)
+ Map<FileName, FileObject> files =
getOrCreateFilesystemCache(filesystem);
+
+ writeLock.lock();
+ try
{
// System.err.println(">>> clear fs " + filesystem);
- Map<FileName, FileObject> files =
getOrCreateFilesystemCache(filesystem);
files.clear();
filesystemCache.remove(filesystem);
}
+ finally
+ {
+ writeLock.unlock();
+ }
}
@SuppressWarnings("unchecked") // (1)
@@ -176,8 +225,8 @@ public class LRUFilesCache extends Abstr
{
// System.err.println(">>> create fs " + filesystem);
- files = new MyLRUMap(filesystem, lruSize); // 1
- filesystemCache.put(filesystem, files);
+ files = new MyLRUMap(filesystem, lruSize);
+ filesystemCache.putIfAbsent(filesystem, files);
}
return files;
@@ -188,20 +237,18 @@ public class LRUFilesCache extends Abstr
{
super.close();
- synchronized (this)
- {
- // System.err.println(">>> clear all");
+ // System.err.println(">>> clear all");
- filesystemCache.clear();
- }
+ filesystemCache.clear();
}
public void removeFile(final FileSystem filesystem, final FileName name)
{
- synchronized (this)
- {
- Map<?, ?> files = getOrCreateFilesystemCache(filesystem);
+ Map<?, ?> files = getOrCreateFilesystemCache(filesystem);
+ writeLock.lock();
+ try
+ {
// System.err.println(">>> " + files.size() + " remove:" +
name.toString());
files.remove(name);
@@ -211,6 +258,10 @@ public class LRUFilesCache extends Abstr
filesystemCache.remove(filesystem);
}
}
+ finally
+ {
+ writeLock.unlock();
+ }
}
public void touchFile(final FileObject file)
Modified:
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/NullFilesCache.java
URL:
http://svn.apache.org/viewvc/commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/NullFilesCache.java?rev=1037973&r1=1037972&r2=1037973&view=diff
==============================================================================
---
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/NullFilesCache.java
(original)
+++
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/NullFilesCache.java
Tue Nov 23 02:27:44 2010
@@ -40,6 +40,11 @@ public class NullFilesCache extends Abst
{
}
+ public boolean putFileIfAbsent(final FileObject file)
+ {
+ return false;
+ }
+
public FileObject getFile(final FileSystem filesystem, final FileName name)
{
return null;
Modified:
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/SoftRefFilesCache.java
URL:
http://svn.apache.org/viewvc/commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/SoftRefFilesCache.java?rev=1037973&r1=1037972&r2=1037973&view=diff
==============================================================================
---
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/SoftRefFilesCache.java
(original)
+++
commons/proper/vfs/trunk/core/src/main/java/org/apache/commons/vfs2/cache/SoftRefFilesCache.java
Tue Nov 23 02:27:44 2010
@@ -31,6 +31,11 @@ import java.lang.ref.SoftReference;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
/**
* This implementation caches every file as long as it is strongly reachable by
@@ -50,13 +55,16 @@ public class SoftRefFilesCache extends A
*/
private final Log log = LogFactory.getLog(SoftRefFilesCache.class);
- private final Map<FileSystem, Map<FileName, Reference<FileObject>>>
filesystemCache =
- new HashMap<FileSystem, Map<FileName, Reference<FileObject>>>();
+ private final ConcurrentMap<FileSystem, Map<FileName,
Reference<FileObject>>> filesystemCache =
+ new ConcurrentHashMap<FileSystem, Map<FileName,
Reference<FileObject>>>();
private final Map<Reference<FileObject>, FileSystemAndNameKey>
refReverseMap =
new HashMap<Reference<FileObject>, FileSystemAndNameKey>(100);
private final ReferenceQueue<FileObject> refqueue = new
ReferenceQueue<FileObject>();
- private SoftRefReleaseThread softRefReleaseThread;
+ private AtomicReference<SoftRefReleaseThread> softRefReleaseThread = new
AtomicReference<SoftRefReleaseThread>();
+
+ private Lock lock = new ReentrantLock();
+
/**
* This thread will listen on the ReferenceQueue and remove the entry in
the
@@ -85,21 +93,23 @@ public class SoftRefFilesCache extends A
continue;
}
- FileSystemAndNameKey key;
- synchronized (refReverseMap)
+ lock.lock();
+ try
{
- key = refReverseMap.get(ref);
- }
+ FileSystemAndNameKey key = refReverseMap.get(ref);
- if (key != null)
- {
- if (removeFile(key))
+ if (key != null)
{
- /* This is not thread safe
- filesystemClose(key.getFileSystem());
- */
+ if (removeFile(key))
+ {
+ filesystemClose(key.getFileSystem());
+ }
}
}
+ finally
+ {
+ lock.unlock();
+ }
}
catch (InterruptedException e)
{
@@ -120,23 +130,31 @@ public class SoftRefFilesCache extends A
private void startThread()
{
- if (softRefReleaseThread != null)
+ Thread thread;
+ SoftRefReleaseThread newThread;
+ do
+ {
+ newThread = null;
+ thread = softRefReleaseThread.get();
+ if (thread != null)
+ {
+ break;
+ }
+ newThread = new SoftRefReleaseThread();
+ } while (softRefReleaseThread.compareAndSet(null, newThread));
+ if (newThread != null)
{
- throw new IllegalStateException(
-
Messages.getString("vfs.impl/SoftRefReleaseThread-already-running.warn"));
+ newThread.start();
}
-
- softRefReleaseThread = new SoftRefReleaseThread();
- softRefReleaseThread.start();
}
private void endThread()
{
- if (softRefReleaseThread != null)
+ SoftRefReleaseThread thread = softRefReleaseThread.getAndSet(null);
+ if (thread != null)
{
- softRefReleaseThread.requestEnd = true;
- softRefReleaseThread.interrupt();
- softRefReleaseThread = null;
+ thread.requestEnd = true;
+ thread.interrupt();
}
}
@@ -150,20 +168,55 @@ public class SoftRefFilesCache extends A
Map<FileName, Reference<FileObject>> files =
getOrCreateFilesystemCache(file.getFileSystem());
Reference<FileObject> ref = createReference(file, refqueue);
- FileSystemAndNameKey key = new FileSystemAndNameKey(file
- .getFileSystem(), file.getName());
+ FileSystemAndNameKey key = new
FileSystemAndNameKey(file.getFileSystem(), file.getName());
- synchronized (files)
+ lock.lock();
+ try
{
Reference<FileObject> old = files.put(file.getName(), ref);
- synchronized (refReverseMap)
+ if (old != null)
{
- if (old != null)
- {
- refReverseMap.remove(old);
- }
- refReverseMap.put(ref, key);
+ refReverseMap.remove(old);
+ }
+ refReverseMap.put(ref, key);
+ }
+ finally
+ {
+ lock.unlock();
+ }
+ }
+
+
+ public boolean putFileIfAbsent(final FileObject file)
+ {
+ if (log.isDebugEnabled())
+ {
+ log.debug("putFile: " + file.getName());
+ }
+
+ Map<FileName, Reference<FileObject>> files =
getOrCreateFilesystemCache(file.getFileSystem());
+
+ Reference<FileObject> ref = createReference(file, refqueue);
+ FileSystemAndNameKey key = new
FileSystemAndNameKey(file.getFileSystem(), file.getName());
+
+ lock.lock();
+ try
+ {
+ if (files.containsKey(file.getName()) &&
files.get(file.getName()).get() != null)
+ {
+ return false;
+ }
+ Reference<FileObject> old = files.put(file.getName(), ref);
+ if (old != null)
+ {
+ refReverseMap.remove(old);
}
+ refReverseMap.put(ref, key);
+ return true;
+ }
+ finally
+ {
+ lock.unlock();
}
}
@@ -176,7 +229,8 @@ public class SoftRefFilesCache extends A
{
Map<FileName, Reference<FileObject>> files =
getOrCreateFilesystemCache(filesystem);
- synchronized (files)
+ lock.lock();
+ try
{
Reference<FileObject> ref = files.get(name);
if (ref == null)
@@ -191,55 +245,61 @@ public class SoftRefFilesCache extends A
}
return fo;
}
+ finally
+ {
+ lock.unlock();
+ }
}
public void clear(FileSystem filesystem)
{
Map<FileName, Reference<FileObject>> files =
getOrCreateFilesystemCache(filesystem);
- boolean closeFilesystem;
-
- synchronized (files)
+ lock.lock();
+ try
{
- synchronized (refReverseMap)
+ Iterator<FileSystemAndNameKey> iterKeys =
refReverseMap.values().iterator();
+ while (iterKeys.hasNext())
{
- Iterator<FileSystemAndNameKey> iterKeys =
refReverseMap.values().iterator();
- while (iterKeys.hasNext())
+ FileSystemAndNameKey key = iterKeys.next();
+ if (key.getFileSystem() == filesystem)
{
- FileSystemAndNameKey key = iterKeys.next();
- if (key.getFileSystem() == filesystem)
- {
- iterKeys.remove();
- files.remove(key.getFileName());
- }
+ iterKeys.remove();
+ files.remove(key.getFileName());
}
+ }
- closeFilesystem = files.size() < 1;
+ if (filesystemCache.size() < 1)
+ {
+ filesystemClose(filesystem);
}
}
-
- if (closeFilesystem)
+ finally
{
- filesystemClose(filesystem);
+ lock.unlock();
}
}
+ /**
+ * Called while the lock is held
+ * @param filesystem The file system to close.
+ */
private void filesystemClose(FileSystem filesystem)
{
if (log.isDebugEnabled())
{
log.debug("close fs: " + filesystem.getRootName());
}
- synchronized (filesystemCache)
+
+ filesystemCache.remove(filesystem);
+ if (filesystemCache.size() < 1)
{
- filesystemCache.remove(filesystem);
- if (filesystemCache.size() < 1)
- {
- endThread();
- }
+ endThread();
}
+ /* This is not thread-safe as another thread might be opening the file
system
((DefaultFileSystemManager) getContext().getFileSystemManager())
._closeFileSystem(filesystem);
+ */
}
@Override
@@ -249,16 +309,17 @@ public class SoftRefFilesCache extends A
endThread();
- // files.clear();
- synchronized (filesystemCache)
+ lock.lock();
+ try
{
filesystemCache.clear();
- }
- synchronized (refReverseMap)
- {
refReverseMap.clear();
}
+ finally
+ {
+ lock.unlock();
+ }
}
public void removeFile(FileSystem filesystem, FileName name)
@@ -282,38 +343,42 @@ public class SoftRefFilesCache extends A
Map<?, ?> files = getOrCreateFilesystemCache(key.getFileSystem());
- synchronized (files)
+ lock.lock();
+ try
{
Object ref = files.remove(key.getFileName());
if (ref != null)
{
- synchronized (refReverseMap)
- {
- refReverseMap.remove(ref);
- }
+ refReverseMap.remove(ref);
}
return files.size() < 1;
}
+ finally
+ {
+ lock.unlock();
+ }
}
protected Map<FileName, Reference<FileObject>>
getOrCreateFilesystemCache(final FileSystem filesystem)
{
- synchronized (filesystemCache)
+ if (filesystemCache.size() < 1)
{
- if (filesystemCache.size() < 1)
- {
- startThread();
- }
+ startThread();
+ }
+
+ Map<FileName, Reference<FileObject>> files;
- Map<FileName, Reference<FileObject>> files =
filesystemCache.get(filesystem);
- if (files == null)
+ do
+ {
+ files = filesystemCache.get(filesystem);
+ if (files != null)
{
- files = new HashMap<FileName, Reference<FileObject>>();
- filesystemCache.put(filesystem, files);
+ break;
}
+ files = new HashMap<FileName, Reference<FileObject>>();
+ } while (filesystemCache.putIfAbsent(filesystem, files) == null);
- return files;
- }
+ return files;
}
}
