001: /*
002: * Copyright (c) 2003 The Visigoth Software Society. All rights
003: * reserved.
004: *
005: * Redistribution and use in source and binary forms, with or without
006: * modification, are permitted provided that the following conditions
007: * are met:
008: *
009: * 1. Redistributions of source code must retain the above copyright
010: * notice, this list of conditions and the following disclaimer.
011: *
012: * 2. Redistributions in binary form must reproduce the above copyright
013: * notice, this list of conditions and the following disclaimer in
014: * the documentation and/or other materials provided with the
015: * distribution.
016: *
017: * 3. The end-user documentation included with the redistribution, if
018: * any, must include the following acknowledgement:
019: * "This product includes software developed by the
020: * Visigoth Software Society (http://www.visigoths.org/)."
021: * Alternately, this acknowledgement may appear in the software itself,
022: * if and wherever such third-party acknowledgements normally appear.
023: *
024: * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
025: * project contributors may be used to endorse or promote products derived
026: * from this software without prior written permission. For written
027: * permission, please contact visigoths@visigoths.org.
028: *
029: * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
030: * nor may "FreeMarker" or "Visigoth" appear in their names
031: * without prior written permission of the Visigoth Software Society.
032: *
033: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
034: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
035: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
036: * DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
037: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
038: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
039: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
040: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
041: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
042: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
043: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
044: * SUCH DAMAGE.
045: * ====================================================================
046: *
047: * This software consists of voluntary contributions made by many
048: * individuals on behalf of the Visigoth Software Society. For more
049: * information on the Visigoth Software Society, please see
050: * http://www.visigoths.org/
051: */
052:
053: package freemarker.ext.beans;
054:
055: import java.util.HashMap;
056: import java.util.Map;
057:
058: import freemarker.template.TemplateHashModel;
059: import freemarker.template.TemplateModel;
060: import freemarker.template.TemplateModelException;
061: import freemarker.template.utility.ClassUtil;
062:
063: /**
064: * Base class for hash models keyed by Java class names.
065: * @author Attila Szegedi
066: * @version $Id: ClassBasedModelFactory.java,v 1.1.2.2 2006/11/12 10:23:02 szegedia Exp $
067: */
068: abstract class ClassBasedModelFactory implements TemplateHashModel {
069: private final BeansWrapper wrapper;
070: private final Map cache = new HashMap();
071:
072: protected ClassBasedModelFactory(BeansWrapper wrapper) {
073: this .wrapper = wrapper;
074: }
075:
076: public TemplateModel get(String key) throws TemplateModelException {
077: synchronized (cache) {
078: TemplateModel model = (TemplateModel) cache.get(key);
079: if (model == null) {
080: try {
081: Class clazz = ClassUtil.forName(key);
082: model = createModel(clazz);
083: // This is called so that we trigger the
084: // class-reloading detector. If there was a class reload,
085: // the wrapper will in turn call our clearCache method.
086: wrapper.introspectClass(clazz);
087: } catch (Exception e) {
088: throw new TemplateModelException(e);
089: }
090: cache.put(key, model);
091: }
092: return model;
093: }
094: }
095:
096: void clearCache() {
097: synchronized (cache) {
098: cache.clear();
099: }
100: }
101:
102: public boolean isEmpty() {
103: return false;
104: }
105:
106: protected abstract TemplateModel createModel(Class clazz)
107: throws TemplateModelException;
108:
109: protected BeansWrapper getWrapper() {
110: return wrapper;
111: }
112: }
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