org.apache.tomcat.util.bcel.classfile.Method Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.tomcat.util.bcel.classfile;
import java.io.DataInputStream;
import java.io.IOException;
import org.apache.tomcat.util.bcel.Constants;
import org.apache.tomcat.util.bcel.util.BCELComparator;
/**
* This class represents the method info structure, i.e., the representation
* for a method in the class. See JVM specification for details.
* A method has access flags, a name, a signature and a number of attributes.
*
* @version $Id: Method.java 1181133 2011-10-10 18:49:14Z markt $
* @author M. Dahm
*/
public final class Method extends FieldOrMethod {
private static final long serialVersionUID = -7447828891136739513L;
private static BCELComparator _cmp = new BCELComparator() {
@Override
public boolean equals( Object o1, Object o2 ) {
Method THIS = (Method) o1;
Method THAT = (Method) o2;
return THIS.getName().equals(THAT.getName())
&& THIS.getSignature().equals(THAT.getSignature());
}
@Override
public int hashCode( Object o ) {
Method THIS = (Method) o;
return THIS.getSignature().hashCode() ^ THIS.getName().hashCode();
}
};
/**
* Empty constructor, all attributes have to be defined via `setXXX'
* methods. Use at your own risk.
*/
public Method() {
}
/**
* Construct object from file stream.
* @param file Input stream
* @throws IOException
* @throws ClassFormatException
*/
Method(DataInputStream file, ConstantPool constant_pool) throws IOException,
ClassFormatException {
super(file, constant_pool);
}
/**
* @return Code attribute of method, if any
*/
public final Code getCode() {
for (int i = 0; i < attributes_count; i++) {
if (attributes[i] instanceof Code) {
return (Code) attributes[i];
}
}
return null;
}
/**
* @return ExceptionTable attribute of method, if any, i.e., list all
* exceptions the method may throw not exception handlers!
*/
public final ExceptionTable getExceptionTable() {
for (int i = 0; i < attributes_count; i++) {
if (attributes[i] instanceof ExceptionTable) {
return (ExceptionTable) attributes[i];
}
}
return null;
}
/** @return LocalVariableTable of code attribute if any, i.e. the call is forwarded
* to the Code atribute.
*/
public final LocalVariableTable getLocalVariableTable() {
Code code = getCode();
if (code == null) {
return null;
}
return code.getLocalVariableTable();
}
/**
* Return string representation close to declaration format,
* `public static void main(String[] args) throws IOException', e.g.
*
* @return String representation of the method.
*/
@Override
public final String toString() {
ConstantUtf8 c;
String name, signature, access; // Short cuts to constant pool
StringBuilder buf;
access = Utility.accessToString(access_flags);
// Get name and signature from constant pool
c = (ConstantUtf8) constant_pool.getConstant(signature_index, Constants.CONSTANT_Utf8);
signature = c.getBytes();
c = (ConstantUtf8) constant_pool.getConstant(name_index, Constants.CONSTANT_Utf8);
name = c.getBytes();
signature = Utility.methodSignatureToString(signature, name, access, true,
getLocalVariableTable());
buf = new StringBuilder(signature);
for (int i = 0; i < attributes_count; i++) {
Attribute a = attributes[i];
if (!((a instanceof Code) || (a instanceof ExceptionTable))) {
buf.append(" [").append(a.toString()).append("]");
}
}
ExceptionTable e = getExceptionTable();
if (e != null) {
String str = e.toString();
if (!str.equals("")) {
buf.append("\n\t\tthrows ").append(str);
}
}
return buf.toString();
}
/**
* Return value as defined by given BCELComparator strategy.
* By default two method objects are said to be equal when
* their names and signatures are equal.
*
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals( Object obj ) {
return _cmp.equals(this, obj);
}
/**
* Return value as defined by given BCELComparator strategy.
* By default return the hashcode of the method's name XOR signature.
*
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
return _cmp.hashCode(this);
}
}