1/*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements.  See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License.  You may obtain a copy of the License at
8 *
9 *      http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17package org.apache.commons.io.input;
18
19import java.io.InputStream;
20
21/**
22 * Closed input stream. This stream returns -1 to all attempts to read
23 * something from the stream.
24 * <p>
25 * Typically uses of this class include testing for corner cases in methods
26 * that accept input streams and acting as a sentinel value instead of a
27 * <code>null</code> input stream.
28 *
29 * @version $Id: ClosedInputStream.java 601751 2007-12-06 14:55:45Z niallp $
30 * @since Commons IO 1.4
31 */
32public class ClosedInputStream extends InputStream {
33
34    /**
35     * A singleton.
36     */
37    public static final ClosedInputStream CLOSED_INPUT_STREAM = new ClosedInputStream();
38
39    /**
40     * Returns -1 to indicate that the stream is closed.
41     *
42     * @return always -1
43     */
44    public int read() {
45        return -1;
46    }
47
48}
49