Source code: com/hp/hpl/jena/shared/wg/LazyInputStream.java
1 /*
2 * (c) Copyright 2000, 2001, 2002, 2003, 2004, 2005 Hewlett-Packard Development Company, LP
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
27 *
28 * LazyZipEntryInputStream.java
29 *
30 * Created on November 28, 2001, 11:38 AM
31 */
32
33 package com.hp.hpl.jena.shared.wg;
34
35
36 import java.io.*;
37
38 /**
39 *In test cases we cannot open all the input files
40 * while creating the test suite, but must defer the
41 * opening until the test is actually run.
42 * @author jjc
43 */
44 abstract class LazyInputStream extends InputStream {
45
46 private InputStream underlying;
47 abstract InputStream open() throws IOException;
48
49 boolean connect() throws IOException {
50 if ( underlying != null )
51 return true;
52 else {
53 underlying = open();
54 }
55 return underlying != null;
56
57 }
58
59
60 public int read() throws IOException {
61 if (underlying == null)
62 underlying = open();
63 return underlying.read();
64 }
65
66 public void close() throws IOException {
67 if (underlying != null) {
68 underlying.close();
69 underlying = null;
70 }
71 }
72
73
74
75 }