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Posted to dev@velocity.apache.org by ge...@locus.apache.org on 2000/12/04 03:04:50 UTC
cvs commit: jakarta-velocity/src/java/org/apache/velocity/runtime/parser/node ASTIdentifier.java
geirm 00/12/03 18:04:50
Modified: src/java/org/apache/velocity/runtime/parser/node
ASTIdentifier.java
Log:
Context/thread safety for introspection. Big rework on interaction between ASTIdentifier and ASTReference.
Revision Changes Path
1.3 +127 -15 jakarta-velocity/src/java/org/apache/velocity/runtime/parser/node/ASTIdentifier.java
Index: ASTIdentifier.java
===================================================================
RCS file: /home/cvs/jakarta-velocity/src/java/org/apache/velocity/runtime/parser/node/ASTIdentifier.java,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- ASTIdentifier.java 2000/10/21 03:21:03 1.2
+++ ASTIdentifier.java 2000/12/04 02:04:48 1.3
@@ -1,5 +1,78 @@
/* Generated By:JJTree: Do not edit this line. ASTIdentifier.java */
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2000 The Apache Software Foundation. All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ * any, must include the following acknowlegement:
+ * "This product includes software developed by the
+ * Apache Software Foundation (http://www.apache.org/)."
+ * Alternately, this acknowlegement may appear in the software itself,
+ * if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
+ * Foundation" must not be used to endorse or promote products derived
+ * from this software without prior written permission. For written
+ * permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ * nor may "Apache" appear in their names without prior written
+ * permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation. For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+/**
+ * ASTIdentifier.java
+ *
+ * Method support for identifiers : $foo
+ *
+ * mainly used by ASTRefrence
+ *
+ * Introspection is now moved to 'just in time' or at render / execution time.
+ * There are many reasons why this has to be done, but the primary two are
+ * thread safety, to remove any context-derived information from class member
+ * variables.
+ *
+ * Please look at the Parser.jjt file which is
+ * what controls the generation of this class.
+ *
+ * @author <a href="mailto:jvanzyl@periapt.com">Jason van Zyl</a>
+ * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
+ * @version $Id: ASTIdentifier.java,v 1.3 2000/12/04 02:04:48 geirm Exp $
+ */
package org.apache.velocity.runtime.parser.node;
import java.util.Map;
@@ -10,8 +83,9 @@
public class ASTIdentifier extends SimpleNode
{
- private AbstractExecutor executor;
-
+ private String method = "";
+ private String identifier = "";
+
public ASTIdentifier(int id)
{
super(id);
@@ -28,34 +102,72 @@
return visitor.visit(this, data);
}
- public Object init(Context context, Object data)
+ /**
+ * simple init - don't do anything that is context specific.
+ * just get what we need from the AST, which is static.
+ */
+ public Object init(Context context, Object data)
throws Exception
{
- String identifier = getFirstToken().image;
- String method = "get" + identifier;
+ super.init( context, data );
+
+ identifier = getFirstToken().image;
+ method = "get" + identifier;
- //! Now there might just be an error here.
- // If there is a typo in the property
- // then a MapExecutor is created and
- // this needs to be prevented.
+ return data;
+ }
+ /**
+ * introspects the class to find the method name of the node,
+ * or if that fails, treats the reference object as a map
+ * and treats the identifier as a key in that map.
+ * This needs work.
+ *
+ * @param data Class to be introspected
+ */
+ private AbstractExecutor doIntrospection( Class data )
+ throws Exception
+ {
+ /*
+ * Now there might just be an error here. If there is a typo in the property
+ * then a MapExecutor is created and this needs to be prevented.
+ */
+
try
{
- executor = new PropertyExecutor();
- Method m = ((Class)data).getMethod(method,null);
+ AbstractExecutor executor = new PropertyExecutor();
+ Method m = data.getMethod(method,null);
executor.setData(m);
- return m.getReturnType();
+ return executor;
}
catch (NoSuchMethodException nsme)
{
- executor = new MapExecutor();
+ AbstractExecutor executor = new MapExecutor();
executor.setData(identifier);
- return Object.class;
+ return executor;
}
}
+ /**
+ * invokes the method on the object passed in
+ */
public Object execute(Object o, Context context)
{
- return executor.execute(o, context);
+ AbstractExecutor executor = null;
+
+ try
+ {
+ Class c = o.getClass();
+ executor = doIntrospection( c );
+ }
+ catch( Exception e)
+ {
+ System.out.println("ASTIdentifier.execute() : identifier = " + identifier + " : " + e );
+ }
+
+ if (executor != null)
+ return executor.execute(o, context);
+ else
+ return null;
}
}