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1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  package org.apache.hadoop.hbase.regionserver;
20  
21  import java.io.FileWriter;
22  import java.io.IOException;
23  import java.util.concurrent.atomic.AtomicBoolean;
24  
25  import org.apache.hadoop.classification.InterfaceAudience;
26  
27  @InterfaceAudience.Private
28  public class DebugPrint {
29  
30  private static final AtomicBoolean enabled = new AtomicBoolean(false);
31    private static final Object sync = new Object();
32    public static StringBuilder out = new StringBuilder();
33  
34    static public void enable() {
35      enabled.set(true);
36    }
37    static public void disable() {
38      enabled.set(false);
39    }
40  
41    static public void reset() {
42      synchronized (sync) {
43        enable(); // someone wants us enabled basically.
44  
45        out = new StringBuilder();
46      }
47    }
48    static public void dumpToFile(String file) throws IOException {
49      FileWriter f = new FileWriter(file);
50      synchronized (sync) {
51        f.write(out.toString());
52      }
53      f.close();
54    }
55  
56    public static void println(String m) {
57      if (!enabled.get()) {
58        System.out.println(m);
59        return;
60      }
61  
62      synchronized (sync) {
63        String threadName = Thread.currentThread().getName();
64        out.append("<");
65        out.append(threadName);
66        out.append("> ");
67        out.append(m);
68        out.append("\n");
69      }
70    }
71  }