001 /**
002 * Java Gui Builder - A library to build GUIs using an XML file.
003 * Copyright 2002, 2003 (C) François Beausoleil
004 *
005 * This library is free software; you can redistribute it and/or
006 * modify it under the terms of the GNU Lesser General Public
007 * License as published by the Free Software Foundation; either
008 * version 2.1 of the License, or (at your option) any later version.
009 *
010 * This library is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
013 * Lesser General Public License for more details.
014 *
015 * You should have received a copy of the GNU Lesser General Public
016 * License along with this library; if not, write to the Free Software
017 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
018 */
019
020 package jgb.handlers.swing;
021
022 import jgb.builder.TagHandler;
023 import jgb.builder.utils.MethodCall;
024 import org.xml.sax.SAXException;
025
026 import java.util.Map;
027
028 /**
029 * @since 0.2a
030 * @author Francois Beausoleil, <a href="mailto:fbos@users.sourceforge.net">fbos@users.sourceforge.net</a>
031 */
032 public class MethodCallTagHandler extends AbstractTagHandler {
033 /**
034 * The name of the method attribute.
035 */
036 protected static final String ATTR_METHOD = "method";
037
038 public void enterElement(Map atts) throws SAXException {
039 Object refObject = getReferenceObject(atts);
040 String methodName = getMethodName(atts);
041 String refObjectClassName = refObject.getClass().getName();
042 MethodCall methodCall = createMethodCall(refObjectClassName, methodName, refObject);
043 putAccumulator(tagContext, methodCall);
044 }
045
046 public void exitElement() throws SAXException {
047 MethodCall methodCall = getContextAccumulator(tagContext);
048 try {
049 Object value = methodCall.call();
050 tagContext.put(TagHandler.CALL_RETURN_CLASS_KEY, methodCall.getReturnValueType());
051 tagContext.put(TagHandler.CALL_RETURN_VALUE_KEY, value);
052 } catch (Exception e) {
053 throwParsingException("could not execute method call", e);
054 }
055
056 tagContext.remove(TagHandler.CURRENT_PARM_ACC_KEY);
057 }
058
059 protected MethodCall getContextAccumulator(Map tagContext) {
060 MethodCall methodCall = (MethodCall)tagContext.get(TagHandler.CURRENT_PARM_ACC_KEY);
061 return methodCall;
062 }
063
064 protected MethodCall createMethodCall(String refObjectClassName, String methodName, Object refObject) throws SAXException {
065 try {
066 return new jgb.builder.utils.MethodCall(refObjectClassName, methodName, refObject);
067 } catch (Exception e) {
068 throwParsingException("could not instantiate method call on "
069 + "objects of class " + refObjectClassName
070 + " with method of name " + methodName, e);
071 }
072
073 return null;
074 }
075
076 protected void putAccumulator(Map tagContext, jgb.builder.utils.MethodCall methodCall) {
077 tagContext.put(TagHandler.CURRENT_PARM_ACC_KEY, methodCall);
078 }
079
080 protected Object getReferenceObject(Map atts) {
081 Object refObject;
082 if ((String)atts.get(ATTR_REFID) == null) {
083 refObject = getCurrentObject();
084 } else {
085 refObject = getObject((String)atts.get(ATTR_REFID));
086 }
087 return refObject;
088 }
089
090 protected String getMethodName(Map atts) {
091 String methodName = (String)atts.get(ATTR_METHOD);
092 return methodName;
093 }
094 }