01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * 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: */
17: package org.apache.commons.io.input;
18:
19: import java.io.IOException;
20: import java.io.InputStream;
21: import java.io.ObjectInputStream;
22: import java.io.ObjectStreamClass;
23: import java.io.StreamCorruptedException;
24:
25: /**
26: * A special ObjectInputStream that loads a class based on a specified
27: * <code>ClassLoader</code> rather than the system default.
28: * <p>
29: * This is useful in dynamic container environments.
30: *
31: * @author Paul Hammant
32: * @version $Id: ClassLoaderObjectInputStream.java 437567 2006-08-28 06:39:07Z bayard $
33: * @since Commons IO 1.1
34: */
35: public class ClassLoaderObjectInputStream extends ObjectInputStream {
36:
37: /** The class loader to use. */
38: private ClassLoader classLoader;
39:
40: /**
41: * Constructs a new ClassLoaderObjectInputStream.
42: *
43: * @param classLoader the ClassLoader from which classes should be loaded
44: * @param inputStream the InputStream to work on
45: * @throws IOException in case of an I/O error
46: * @throws StreamCorruptedException if the stream is corrupted
47: */
48: public ClassLoaderObjectInputStream(ClassLoader classLoader,
49: InputStream inputStream) throws IOException,
50: StreamCorruptedException {
51: super (inputStream);
52: this .classLoader = classLoader;
53: }
54:
55: /**
56: * Resolve a class specified by the descriptor using the
57: * specified ClassLoader or the super ClassLoader.
58: *
59: * @param objectStreamClass descriptor of the class
60: * @return the Class object described by the ObjectStreamClass
61: * @throws IOException in case of an I/O error
62: * @throws ClassNotFoundException if the Class cannot be found
63: */
64: protected Class resolveClass(ObjectStreamClass objectStreamClass)
65: throws IOException, ClassNotFoundException {
66:
67: Class clazz = Class.forName(objectStreamClass.getName(), false,
68: classLoader);
69:
70: if (clazz != null) {
71: // the classloader knows of the class
72: return clazz;
73: } else {
74: // classloader knows not of class, let the super classloader do it
75: return super.resolveClass(objectStreamClass);
76: }
77: }
78: }
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