1/*
2 * Copyright (C) 2007 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
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
17package com.google.common.io;
18
19import com.google.common.annotations.Beta;
20
21import java.io.Flushable;
22import java.io.IOException;
23import java.util.logging.Level;
24import java.util.logging.Logger;
25
26/**
27 * Utility methods for working with {@link Flushable} objects.
28 *
29 * @author Michael Lancaster
30 * @since 1.0
31 */
32@Beta
33public final class Flushables {
34  private static final Logger logger
35      = Logger.getLogger(Flushables.class.getName());
36
37  private Flushables() {}
38
39  /**
40   * Flush a {@link Flushable}, with control over whether an
41   * {@code IOException} may be thrown.
42   *
43   * <p>If {@code swallowIOException} is true, then we don't rethrow
44   * {@code IOException}, but merely log it.
45   *
46   * @param flushable the {@code Flushable} object to be flushed.
47   * @param swallowIOException if true, don't propagate IO exceptions
48   *     thrown by the {@code flush} method
49   * @throws IOException if {@code swallowIOException} is false and
50   *     {@link Flushable#flush} throws an {@code IOException}.
51   * @see Closeables#close
52   */
53  public static void flush(Flushable flushable, boolean swallowIOException)
54      throws IOException {
55    try {
56      flushable.flush();
57    } catch (IOException e) {
58      if (swallowIOException) {
59        logger.log(Level.WARNING,
60            "IOException thrown while flushing Flushable.", e);
61      } else {
62        throw e;
63      }
64    }
65  }
66
67  /**
68   * Equivalent to calling {@code flush(flushable, true)}, but with no
69   * {@code IOException} in the signature.
70   *
71   * @param flushable the {@code Flushable} object to be flushed.
72   */
73  public static void flushQuietly(Flushable flushable) {
74    try {
75      flush(flushable, true);
76    } catch (IOException e) {
77      logger.log(Level.SEVERE, "IOException should not have been thrown.", e);
78    }
79  }
80}
81