01: /*
02: * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
03: *
04: * This file is part of Resin(R) Open Source
05: *
06: * Each copy or derived work must preserve the copyright notice and this
07: * notice unmodified.
08: *
09: * Resin Open Source is free software; you can redistribute it and/or modify
10: * it under the terms of the GNU General Public License as published by
11: * the Free Software Foundation; either version 2 of the License, or
12: * (at your option) any later version.
13: *
14: * Resin Open Source is distributed in the hope that it will be useful,
15: * but WITHOUT ANY WARRANTY; without even the implied warranty of
16: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
17: * of NON-INFRINGEMENT. See the GNU General Public License for more
18: * details.
19: *
20: * You should have received a copy of the GNU General Public License
21: * along with Resin Open Source; if not, write to the
22: * Free SoftwareFoundation, Inc.
23: * 59 Temple Place, Suite 330
24: * Boston, MA 02111-1307 USA
25: *
26: * @author Scott Ferguson
27: */
28:
29: package com.caucho.el;
30:
31: import com.caucho.loader.EnvironmentClassLoader;
32:
33: import javax.el.ELContext;
34: import javax.el.ELResolver;
35:
36: /**
37: * Creates a variable resolver based on the classloader.
38: */
39: public class EnvironmentResolver extends AbstractVariableResolver {
40: private ClassLoader _loader;
41:
42: /**
43: * Creates the resolver
44: */
45: public EnvironmentResolver(ClassLoader loader, ELResolver parent) {
46: super (parent);
47:
48: _loader = loader;
49: }
50:
51: /**
52: * Returns the named variable value.
53: */
54: public Object getValue(ELContext context, Object base,
55: Object property) {
56: String var = (String) base;
57:
58: for (ClassLoader loader = _loader; loader != null; loader = loader
59: .getParent()) {
60: if (loader instanceof EnvironmentClassLoader) {
61: Object value = EL.getLevelVar(var, loader);
62:
63: if (value == EL.NULL)
64: return null;
65: else if (value != null)
66: return value;
67: }
68: }
69:
70: Object value = EL.getLevelVar(var, null);
71:
72: if (value == EL.NULL)
73: return null;
74: else if (value != null)
75: return value;
76: else
77: return super.getValue(context, var, property);
78: }
79: }
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