Author: oheger
Date: Fri May 10 19:14:27 2013
New Revision: 1481150
URL: http://svn.apache.org/r1481150
Log:
Added new SynchronizerSupport interface.
Added:
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/sync/LockMode.java
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/sync/SynchronizerSupport.java
Added:
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/sync/LockMode.java
URL:
http://svn.apache.org/viewvc/commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/sync/LockMode.java?rev=1481150&view=auto
==============================================================================
---
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/sync/LockMode.java
(added)
+++
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/sync/LockMode.java
Fri May 10 19:14:27 2013
@@ -0,0 +1,51 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.configuration.sync;
+
+/**
+ * <p>
+ * An enumeration used by {@link SynchronizerSupport} to specify how an object
+ * is locked.
+ * </p>
+ * <p>
+ * The {@code SynchronizerSupport} interface allows locking an object. This can
+ * be done in different ways controlling the level of concurrency still
possible
+ * with the object. One of the constants defined here can be passed in when
+ * calling the {@code lock()} method of a {@code SynchronizerSupport} object.
+ * (Note that at the end of the day it is up to a concrete implementation of
+ * {@link Synchronizer} how these lock modes are interpreted.)
+ * </p>
+ *
+ * @version $Id: $
+ * @since 2.0
+ */
+public enum LockMode
+{
+ /**
+ * Lock mode <em>READ</em>. The object is accessed in a read-only manner.
+ * Typically, this means that other read locks can be granted while
+ * concurrent writes are not permitted.
+ */
+ READ,
+
+ /**
+ * Lock mode <em>WRITE</em>. The object is updated. This usually means that
+ * this object is exclusively locked. Attempts of other readers or writers
+ * will block until the current update operation is complete.
+ */
+ WRITE
+}
Added:
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/sync/SynchronizerSupport.java
URL:
http://svn.apache.org/viewvc/commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/sync/SynchronizerSupport.java?rev=1481150&view=auto
==============================================================================
---
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/sync/SynchronizerSupport.java
(added)
+++
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/sync/SynchronizerSupport.java
Fri May 10 19:14:27 2013
@@ -0,0 +1,103 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.configuration.sync;
+
+/**
+ * <p>
+ * Definition of an interface for objects that can be associated with a
+ * {@link Synchronizer}.
+ * </p>
+ * <p>
+ * This interface defines methods for querying and setting the
+ * {@code Synchronizer}. In addition, it is possible to lock the object for a
+ * certain operation. This is useful if some complex operations are to be
+ * performed on the {@code SynchronizerSupport} object in an atomic way.
+ * </p>
+ * <p>
+ * Note that the actual effect of these methods depends on the concrete
+ * {@code Synchronizer} implementation in use! If only a dummy
+ * {@code Synchronizer} is involved (which is appropriate if objects are only
+ * accessed by a single thread), locking an object does not really prohibit
+ * concurrent access.
+ * </p>
+ *
+ * @version $Id: $
+ * @since 2.0
+ */
+public interface SynchronizerSupport
+{
+ /**
+ * Returns the {@code Synchronizer} used by this object. An implementation
+ * must not return <b>null</b>. If no {@code Synchronizer} has been set so
+ * far, a meaningful default {@code Synchronizer} has to be returned.
+ *
+ * @return the {@code Synchronizer} used by this object
+ */
+ Synchronizer getSynchronizer();
+
+ /**
+ * Sets the {@code Synchronizer} to be used by this object. Calling this
+ * method and setting an appropriate {@code Synchronizer} determines
whether
+ * this object can be accessed in a thread-safe way or not. The argument
may
+ * be <b>null</b>; in this case an implementation should switch to a
default
+ * {@code Synchronizer}.
+ *
+ * @param sync the {@code Synchronizer} for this object
+ */
+ void setSynchronizer(Synchronizer sync);
+
+ /**
+ * Locks this object for the specified mode. This call may block until this
+ * object is released from other lock operations. When it returns the
caller
+ * can access the object in a way compatible to the specified
+ * {@code LockMode}. When done the {@code unlock()} must be called with the
+ * same {@code LockMode} argument. In practice, a <b>try</b>-<b>finally</b>
+ * construct should be used as in the following example:
+ *
+ * <pre>
+ * SynchronizerSupport syncSupport = ...;
+ * syncSupport.lock(LockMode.READ);
+ * try
+ * {
+ * // read access to syncSupport
+ * }
+ * finally
+ * {
+ * syncSupport.unlock(LockMode.READ);
+ * }
+ * </pre>
+ *
+ * <em>Note:</em> Always use this method for obtaining a lock rather than
+ * accessing the object's {@link Synchronizer} directly. An implementation
+ * may perform additional actions which are not executed when only
+ * interacting with the {@code Synchronizer}.
+ *
+ * @param mode the {@code LockMode}
+ */
+ void lock(LockMode mode);
+
+ /**
+ * Releases a lock of this object that was obtained using the
+ * {@link #lock(LockMode)} method. This method must always be called
+ * pair-wise with {@code lock()}. The argument must match to the one passed
+ * to the corresponding {@code lock()} call; otherwise, the behavior of the
+ * {@link Synchronizer} is unspecified.
+ *
+ * @param mode the {@code LockMode}
+ */
+ void unlock(LockMode mode);
+}
