jvanzyl 00/10/30 18:48:49
Added: src/java/org/apache/velocity/util/introspection
ClassMethodMap.java Introspector.java
Log:
- start of new introspection engine.
Revision Changes Path
1.1
jakarta-velocity/src/java/org/apache/velocity/util/introspection/ClassMethodMap.java
Index: ClassMethodMap.java
===================================================================
package org.apache.velocity.util.introspection;
/*
* 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", "Velocity", 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 [EMAIL PROTECTED]
*
* 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/>.
*/
import java.util.Hashtable;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
public class ClassMethodMap extends Hashtable
{
private Class clazz;
private Hashtable directHits = new Hashtable();
public ClassMethodMap(Class clazz)
{
this.clazz = clazz;
populateDirectHits();
}
public Method findMethod(String key)
{
return (Method) directHits.get(key);
}
private void populateDirectHits()
{
Method[] methods = clazz.getMethods();
StringBuffer methodKey;
for (int i = 0; i < methods.length; i++)
if (Modifier.isPublic(methods[i].getModifiers()))
directHits.put(makeMethodKey(methods[i]), methods[i]);
}
private String makeMethodKey(Method method)
{
Class[] parameterTypes = method.getParameterTypes();
StringBuffer methodKey = new StringBuffer().append(method.getName());
for (int j = 0; j < parameterTypes.length; j++)
methodKey.append(parameterTypes[j].getName());
return methodKey.toString();
}
}
1.1
jakarta-velocity/src/java/org/apache/velocity/util/introspection/Introspector.java
Index: Introspector.java
===================================================================
package org.apache.velocity.util.introspection;
/*
* 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", "Velocity", 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 [EMAIL PROTECTED]
*
* 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/>.
*/
import java.util.Hashtable;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
/**
* This basic function of this class is to return a Method
* object for a particular class given the name of a method
* and the parameters to the method in the form of an Object[]
*
* The first time the Introspector sees a
* class it creates a class method map for the
* class in question. Basically the class method map
* is a Hastable where Method objects are keyed by a
* concatenation of the method name and the names of
* classes that make up the parameters.
*
* For example, a method with the following signature:
*
* public void method(String a, StringBuffer b)
*
* would be mapped by the key:
*
* "method" + "java.lang.String" + "java.lang.StringBuffer"
*
* This mapping is performed for all the methods in a class
* and stored for
* @author <a href="mailto:[EMAIL PROTECTED]">Jason van Zyl</a>
* @version $Id: Introspector.java,v 1.1 2000/10/31 02:48:49 jvanzyl Exp $
*/
// isAssignable checks for arguments that are subclasses
// DirectHit map
// DirectMiss map
public class Introspector
{
private static Hashtable classMethodMaps = new Hashtable();
public static Method getMethod(Class c, String name, Object[] params)
throws Exception
{
// If this is the first time seeing this class
// then create a method map for this class and
// store it in Hashtable of class method maps.
if (!classMethodMaps.containsKey(c.getName()))
classMethodMaps.put(c.getName(), new ClassMethodMap(c));
return findMethod(c, name, params);
}
private static Method findMethod(Class c, String name, Object[] params)
{
// Get the class method map for the class in
// question.
ClassMethodMap classMethodMap = (ClassMethodMap)
classMethodMaps.get(c.getName());
// Return the method based method key.
Method method = classMethodMap.findMethod(makeMethodKey(name, params));
return method;
}
private static String makeMethodKey(String method, Object[] params)
{
StringBuffer methodKey = new StringBuffer().append(method);
for (int j = 0; j < params.length; j++)
methodKey.append(params[j].getClass().getName());
return methodKey.toString();
}
private static class Test
{
public void method(String a, String b)
{
System.out.println("String, String");
}
public void method(String a, StringBuffer b)
{
System.out.println("String, StringBuffer");
}
}
public static void main (String[] arg) throws Exception
{
// The problem to deal with is when the
// params types have a null in them. then
// you can't tell. Then we could compare
// by number of parameters.
Object[] params =
{
new String(),
new String()
};
Object[] args =
{
"this",
"that"
};
Test t = new Test();
Method m = getMethod(t.getClass(), "method", params);
m.invoke(t, args);
}
}
