01: /*
02: * (c) Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Hewlett-Packard Development Company, LP
03: * All rights reserved.
04: *
05: * Redistribution and use in source and binary forms, with or without
06: * modification, are permitted provided that the following conditions
07: * are met:
08: * 1. Redistributions of source code must retain the above copyright
09: * 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: import java.io.*;
36:
37: /**
38: *In test cases we cannot open all the input files
39: * while creating the test suite, but must defer the
40: * opening until the test is actually run.
41: * @author jjc
42: */
43: abstract class LazyInputStream extends InputStream {
44:
45: private InputStream underlying;
46:
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: public int read() throws IOException {
60: if (underlying == null)
61: underlying = open();
62: return underlying.read();
63: }
64:
65: public void close() throws IOException {
66: if (underlying != null) {
67: underlying.close();
68: underlying = null;
69: }
70: }
71:
72: }
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