pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / util / TwoPhaseCommit.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/util/TwoPhaseCommit.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/util/TwoPhaseCommit.java
new file mode 100644 (file)
index 0000000..efd2d69
--- /dev/null
+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/util/TwoPhaseCommit.java
@@ -0,0 +1,77 @@
+package org.apache.lucene.util;
+
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * 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.
+ */
+
+/**
+ * An interface for implementations that support 2-phase commit. You can use
+ * {@link TwoPhaseCommitTool} to execute a 2-phase commit algorithm over several
+ * {@link TwoPhaseCommit}s.
+ * 
+ * @lucene.experimental
+ */
+public interface TwoPhaseCommit {
+
+  /**
+   * The first stage of a 2-phase commit. Implementations should do as much work
+   * as possible in this method, but avoid actual committing changes. If the
+   * 2-phase commit fails, {@link #rollback()} is called to discard all changes
+   * since last successful commit.
+   */
+  public void prepareCommit() throws IOException;
+
+  /**
+   * Like {@link #commit()}, but takes an additional commit data to be included
+   * w/ the commit.
+   * <p>
+   * <b>NOTE:</b> some implementations may not support any custom data to be
+   * included w/ the commit and may discard it altogether. Consult the actual
+   * implementation documentation for verifying if this is supported.
+   * 
+   * @see #prepareCommit()
+   */
+  public void prepareCommit(Map<String, String> commitData) throws IOException;
+
+  /**
+   * The second phase of a 2-phase commit. Implementations should ideally do
+   * very little work in this method (following {@link #prepareCommit()}, and
+   * after it returns, the caller can assume that the changes were successfully
+   * committed to the underlying storage.
+   */
+  public void commit() throws IOException;
+
+  /**
+   * Like {@link #commit()}, but takes an additional commit data to be included
+   * w/ the commit.
+   * 
+   * @see #commit()
+   * @see #prepareCommit(Map)
+   */
+  public void commit(Map<String, String> commitData) throws IOException;
+
+  /**
+   * Discards any changes that have occurred since the last commit. In a 2-phase
+   * commit algorithm, where one of the objects failed to {@link #commit()} or
+   * {@link #prepareCommit()}, this method is used to roll all other objects
+   * back to their previous state.
+   */
+  public void rollback() throws IOException;
+
+}