01: /*
02: * Copyright 2004-2006 the original author or authors.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
10: * Unless required by applicable law or agreed to in writing, software
11: * distributed under the License is distributed on an "AS IS" BASIS,
12: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13: * See the License for the specific language governing permissions and
14: * limitations under the License.
15: */
16:
17: package org.apache.lucene.store;
18:
19: import java.io.IOException;
20: import java.sql.Connection;
21:
22: import javax.sql.DataSource;
23:
24: import org.apache.lucene.store.jdbc.JdbcDirectory;
25: import org.apache.lucene.store.jdbc.datasource.DataSourceUtils;
26:
27: /**
28: * A simple directory template for performing operations that result in actions being performed on the
29: * directory (like index reader/searcher/writer operation). Helps in having the same code base when working
30: * with different implementation of Lucene <code>Directory</code>, or switching between un-managed and managed
31: * transactions with {@link JdbcDirectory}.
32: * <p/>
33: * Will work with any type of <code>Directory</code> implementation. Special actions will be taken if the
34: * {@link JdbcDirectory} is used, where {@link DataSourceUtils#commitConnectionIfPossible(java.sql.Connection)} will
35: * be called after the callback method.
36: *
37: * @author kimchy
38: */
39: public class DirectoryTemplate {
40:
41: public static interface DirectoryCallback {
42:
43: Object doInDirectory(Directory dir) throws IOException;
44: }
45:
46: public static abstract class DirectoryCallbackWithoutResult
47: implements DirectoryCallback {
48:
49: public Object doInDirectory(Directory dir) throws IOException {
50: doInDirectoryWithoutResult(dir);
51: return null;
52: }
53:
54: protected abstract void doInDirectoryWithoutResult(Directory dir)
55: throws IOException;
56: }
57:
58: private DataSource dataSource;
59:
60: private Directory dir;
61:
62: public DirectoryTemplate(Directory dir) {
63: this .dir = dir;
64: if (dir instanceof JdbcDirectory) {
65: this .dataSource = ((JdbcDirectory) dir).getDataSource();
66: }
67: }
68:
69: public void execute(DirectoryCallback callback) throws IOException {
70: if (dataSource == null) {
71: callback.doInDirectory(dir);
72: return;
73: }
74: Connection conn = DataSourceUtils.getConnection(dataSource);
75: try {
76: callback.doInDirectory(dir);
77: DataSourceUtils.commitConnectionIfPossible(conn);
78: } catch (IOException e) {
79: DataSourceUtils.safeRollbackConnectionIfPossible(conn);
80: throw e;
81: } finally {
82: DataSourceUtils.releaseConnection(conn);
83: }
84: }
85: }
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