| ParamReader.java |
/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 2002-2003 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 acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Axis" 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 name, without prior written
* permission of the Apache Software Foundation.
*
* 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/>.
*/
package org.jboss.axis.utils.bytecode;
import org.jboss.axis.utils.Messages;
import java.io.IOException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Map;
/**
* This is the class file reader for obtaining the parameter names
* for declared methods in a class. The class must have debugging
* attributes for us to obtain this information. <p>
* <p/>
* This does not work for inherited methods. To obtain parameter
* names for inherited methods, you must use a paramReader for the
* class that originally declared the method. <p>
* <p/>
* don't get tricky, it's the bare minimum. Instances of this class
* are not threadsafe -- don't share them. <p>
*
* @author Edwin Smith, Macromedia
*/
public class ParamReader
extends ClassReader
{
private String methodName;
private Map methods = new HashMap();
private Class[] paramTypes;
/**
* process a class file, given it's class. We'll use the defining
* classloader to locate the bytecode.
*
* @param c
* @throws IOException
*/
public ParamReader(Class c) throws IOException
{
this(getBytes(c));
}
/**
* process the given class bytes directly.
*
* @param b
* @throws IOException
*/
public ParamReader(byte[] b) throws IOException
{
super(b, findAttributeReaders(ParamReader.class));
// check the magic number
if (readInt() != 0xCAFEBABE)
{
// not a class file!
throw new IOException(Messages.getMessage("badClassFile00"));
}
readShort(); // minor version
readShort(); // major version
readCpool(); // slurp in the constant pool
readShort(); // access flags
readShort(); // this class name
readShort(); // super class name
int count = readShort(); // ifaces count
for (int i = 0; i < count; i++)
{
readShort(); // interface index
}
count = readShort(); // fields count
for (int i = 0; i < count; i++)
{
readShort(); // access flags
readShort(); // name index
readShort(); // descriptor index
skipAttributes(); // field attributes
}
count = readShort(); // methods count
for (int i = 0; i < count; i++)
{
readShort(); // access flags
int m = readShort(); // name index
String name = resolveUtf8(m);
int d = readShort(); // descriptor index
this.methodName = name + resolveUtf8(d);
readAttributes(); // method attributes
}
}
public void readCode() throws IOException
{
readShort(); // max stack
int maxLocals = readShort(); // max locals
MethodInfo info = new MethodInfo(maxLocals);
if (methods != null && methodName != null)
{
methods.put(methodName, info);
}
skipFully(readInt()); // code
skipFully(8 * readShort()); // exception table
// read the code attributes (recursive). This is where
// we will find the LocalVariableTable attribute.
readAttributes();
}
/**
* return the names of the declared parameters for the given method.
* If we cannot determine the names, return null. The returned array will
* have one name per parameter. The length of the array will be the same
* as the length of the Class[] array returned by Method.getParameterTypes().
*
* @param method
* @return String[] array of names, one per parameter, or null
*/
public String[] getParameterNames(Method method)
{
paramTypes = method.getParameterTypes();
// look up the names for this method
MethodInfo info = (MethodInfo)methods.get(getSignature(method, paramTypes));
// we know all the local variable names, but we only need to return
// the names of the parameters.
if (info != null)
{
String[] paramNames = new String[paramTypes.length];
int j = Modifier.isStatic(method.getModifiers()) ? 0 : 1;
boolean found = false; // did we find any non-null names
for (int i = 0; i < paramNames.length; i++)
{
if (info.names[j] != null)
{
found = true;
paramNames[i] = info.names[j];
}
j++;
if (paramTypes[i] == double.class || paramTypes[i] == long.class)
{
// skip a slot for 64bit params
j++;
}
}
if (found)
{
return paramNames;
}
else
{
return null;
}
}
else
{
return null;
}
}
private static class MethodInfo
{
String[] names;
int maxLocals;
public MethodInfo(int maxLocals)
{
this.maxLocals = maxLocals;
names = new String[maxLocals];
}
}
private MethodInfo getMethodInfo()
{
MethodInfo info = null;
if (methods != null && methodName != null)
{
info = (MethodInfo)methods.get(methodName);
}
return info;
}
/**
* this is invoked when a LocalVariableTable attribute is encountered.
*
* @throws IOException
*/
public void readLocalVariableTable() throws IOException
{
int len = readShort(); // table length
MethodInfo info = getMethodInfo();
for (int j = 0; j < len; j++)
{
readShort(); // start pc
readShort(); // length
int nameIndex = readShort(); // name_index
readShort(); // descriptor_index
int index = readShort(); // local index
if (info != null)
{
info.names[index] = resolveUtf8(nameIndex);
}
}
}
}
| ParamReader.java |