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The AspectJ weaver introduces advices to java classes
package org.aspectj.apache.bcel.generic;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 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 "Apache" and "Apache Software Foundation" and
* "Apache BCEL" 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",
* "Apache BCEL", 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
* ");
}
/**
* Return true iff this type is castable to another type t as defined in the JVM specification. The case where this is Type.NULL
* is not defined (see the CHECKCAST definition in the JVM specification). However, because e.g. CHECKCAST doesn't throw a
* ClassCastException when casting a null reference to any Object, true is returned in this case.
*/
public boolean isCastableTo(Type t) {
if (this.equals(Type.NULL)) {
return true; // If this is ever changed in isAssignmentCompatible()
}
return isAssignmentCompatibleWith(t);
/*
* Yes, it's true: It's the same definition. See vmspec2 AASTORE / CHECKCAST definitions.
*/
}
/**
* Return true iff this is assignment compatible with another type t as defined in the JVM specification; see the AASTORE
* definition there.
*/
public boolean isAssignmentCompatibleWith(Type t) {
if (!(t instanceof ReferenceType)) {
return false;
}
ReferenceType T = (ReferenceType) t;
if (this.equals(Type.NULL)) {
return true; // This is not explicitely stated, but clear. Isn't it?
}
/*
* If this is a class type then
*/
if (this instanceof ObjectType && ((ObjectType) this).referencesClass()) {
/*
* If T is a class type, then this must be the same class as T, or this must be a subclass of T;
*/
if (T instanceof ObjectType && ((ObjectType) T).referencesClass()) {
if (this.equals(T)) {
return true;
}
if (Repository.instanceOf(((ObjectType) this).getClassName(), ((ObjectType) T).getClassName())) {
return true;
}
}
/*
* If T is an interface type, this must implement interface T.
*/
if (T instanceof ObjectType && ((ObjectType) T).referencesInterface()) {
if (Repository.implementationOf(((ObjectType) this).getClassName(), ((ObjectType) T).getClassName())) {
return true;
}
}
}
/*
* If this is an interface type, then:
*/
if (this instanceof ObjectType && ((ObjectType) this).referencesInterface()) {
/*
* If T is a class type, then T must be Object (2.4.7).
*/
if (T instanceof ObjectType && ((ObjectType) T).referencesClass()) {
if (T.equals(Type.OBJECT)) {
return true;
}
}
/*
* If T is an interface type, then T must be the same interface as this or a superinterface of this (2.13.2).
*/
if (T instanceof ObjectType && ((ObjectType) T).referencesInterface()) {
if (this.equals(T)) {
return true;
}
if (Repository.implementationOf(((ObjectType) this).getClassName(), ((ObjectType) T).getClassName())) {
return true;
}
}
}
/*
* If this is an array type, namely, the type SC[], that is, an array of components of type SC, then:
*/
if (this instanceof ArrayType) {
/*
* If T is a class type, then T must be Object (2.4.7).
*/
if (T instanceof ObjectType && ((ObjectType) T).referencesClass()) {
if (T.equals(Type.OBJECT)) {
return true;
}
}
/*
* If T is an array type TC[], that is, an array of components of type TC, then one of the following must be true:
*/
if (T instanceof ArrayType) {
/*
* TC and SC are the same primitive type (2.4.1).
*/
Type sc = ((ArrayType) this).getElementType();
Type tc = ((ArrayType) this).getElementType();
if (sc instanceof BasicType && tc instanceof BasicType && sc.equals(tc)) {
return true;
}
/*
* TC and SC are reference types (2.4.6), and type SC is assignable to TC by these runtime rules.
*/
if (tc instanceof ReferenceType && sc instanceof ReferenceType
&& ((ReferenceType) sc).isAssignmentCompatibleWith(tc)) {
return true;
}
}
/* If T is an interface type, T must be one of the interfaces implemented by arrays (2.15). */
// TODO: Check if this is still valid or find a way to dynamically find out which
// interfaces arrays implement. However, as of the JVM specification edition 2, there
// are at least two different pages where assignment compatibility is defined and
// on one of them "interfaces implemented by arrays" is exchanged with "'Cloneable' or
// 'java.io.Serializable'"
if (T instanceof ObjectType && ((ObjectType) T).referencesInterface()) {
for (int ii = 0; ii < Constants.INTERFACES_IMPLEMENTED_BY_ARRAYS.length; ii++) {
if (T.equals(new ObjectType(Constants.INTERFACES_IMPLEMENTED_BY_ARRAYS[ii]))) {
return true;
}
}
}
}
return false; // default.
}
/**
* This commutative operation returns the first common superclass (narrowest ReferenceType referencing a class, not an
* interface). If one of the types is a superclass of the other, the former is returned. If "this" is Type.NULL, then t is
* returned. If t is Type.NULL, then "this" is returned. If "this" equals t ['this.equals(t)'] "this" is returned. If "this" or
* t is an ArrayType, then Type.OBJECT is returned; unless their dimensions match. Then an ArrayType of the same number of
* dimensions is returned, with its basic type being the first common super class of the basic types of "this" and t. If "this"
* or t is a ReferenceType referencing an interface, then Type.OBJECT is returned. If not all of the two classes' superclasses
* cannot be found, "null" is returned. See the JVM specification edition 2, "4.9.2 The Bytecode Verifier".
*/
public ReferenceType getFirstCommonSuperclass(ReferenceType t) {
if (this.equals(Type.NULL)) {
return t;
}
if (t.equals(Type.NULL)) {
return this;
}
if (this.equals(t)) {
return this;
/*
* TODO: Above sounds a little arbitrary. On the other hand, there is no object referenced by Type.NULL so we can also
* say all the objects referenced by Type.NULL were derived from java.lang.Object. However, the Java Language's
* "instanceof" operator proves us wrong: "null" is not referring to an instance of java.lang.Object :)
*/
}
/* This code is from a bug report by Konstantin Shagin */
if (this instanceof ArrayType && t instanceof ArrayType) {
ArrayType arrType1 = (ArrayType) this;
ArrayType arrType2 = (ArrayType) t;
if (arrType1.getDimensions() == arrType2.getDimensions() && arrType1.getBasicType() instanceof ObjectType
&& arrType2.getBasicType() instanceof ObjectType) {
return new ArrayType(((ObjectType) arrType1.getBasicType()).getFirstCommonSuperclass((ObjectType) arrType2
.getBasicType()), arrType1.getDimensions());
}
}
if (this instanceof ArrayType || t instanceof ArrayType) {
return Type.OBJECT;
// TODO: Is there a proof of OBJECT being the direct ancestor of every ArrayType?
}
if (this instanceof ObjectType && ((ObjectType) this).referencesInterface() || t instanceof ObjectType
&& ((ObjectType) t).referencesInterface()) {
return Type.OBJECT;
// TODO: The above line is correct comparing to the vmspec2. But one could
// make class file verification a bit stronger here by using the notion of
// superinterfaces or even castability or assignment compatibility.
}
// this and t are ObjectTypes, see above.
ObjectType thiz = (ObjectType) this;
ObjectType other = (ObjectType) t;
JavaClass[] thiz_sups = Repository.lookupClass(thiz.getClassName()).getSuperClasses();// getSuperClasses(thiz.getClassName());
JavaClass[] other_sups = Repository.lookupClass(other.getClassName()).getSuperClasses();// getSuperClasses(other.getClassName());
if (thiz_sups == null || other_sups == null) {
return null;
}
// Waaahh...
JavaClass[] this_sups = new JavaClass[thiz_sups.length + 1];
JavaClass[] t_sups = new JavaClass[other_sups.length + 1];
System.arraycopy(thiz_sups, 0, this_sups, 1, thiz_sups.length);
System.arraycopy(other_sups, 0, t_sups, 1, other_sups.length);
this_sups[0] = Repository.lookupClass(thiz.getClassName());
t_sups[0] = Repository.lookupClass(other.getClassName());
for (int i = 0; i < t_sups.length; i++) {
for (int j = 0; j < this_sups.length; j++) {
if (this_sups[j].equals(t_sups[i])) {
return new ObjectType(this_sups[j].getClassName());
}
}
}
// Huh? Did you ask for Type.OBJECT's superclass??
return null;
}
// /**
// * This commutative operation returns the first common superclass (narrowest ReferenceType referencing a class, not an
// * interface). If one of the types is a superclass of the other, the former is returned. If "this" is Type.NULL, then t is
// * returned. If t is Type.NULL, then "this" is returned. If "this" equals t ['this.equals(t)'] "this" is returned. If "this"
// or
// * t is an ArrayType, then Type.OBJECT is returned. If "this" or t is a ReferenceType referencing an interface, then
// Type.OBJECT
// * is returned. If not all of the two classes' superclasses cannot be found, "null" is returned. See the JVM specification
// * edition 2, "4.9.2 The Bytecode Verifier".
// *
// * @deprecated use getFirstCommonSuperclass(ReferenceType t) which has slightly changed semantics.
// */
// public ReferenceType firstCommonSuperclass(ReferenceType t) {
// if (this.equals(Type.NULL)) {
// return t;
// }
// if (t.equals(Type.NULL)) {
// return this;
// }
// if (this.equals(t)) {
// return this;
// /*
// * TODO: Above sounds a little arbitrary. On the other hand, there is no object referenced by Type.NULL so we can also
// * say all the objects referenced by Type.NULL were derived from java.lang.Object. However, the Java Language's
// * "instanceof" operator proves us wrong: "null" is not referring to an instance of java.lang.Object :)
// */
// }
//
// if (this instanceof ArrayType || t instanceof ArrayType) {
// return Type.OBJECT;
// // TODO: Is there a proof of OBJECT being the direct ancestor of every ArrayType?
// }
//
// if (this instanceof ObjectType && ((ObjectType) this).referencesInterface() || t instanceof ObjectType
// && ((ObjectType) t).referencesInterface()) {
// return Type.OBJECT;
// // TODO: The above line is correct comparing to the vmspec2. But one could
// // make class file verification a bit stronger here by using the notion of
// // superinterfaces or even castability or assignment compatibility.
// }
//
// // this and t are ObjectTypes, see above.
// ObjectType thiz = (ObjectType) this;
// ObjectType other = (ObjectType) t;
// JavaClass[] thiz_sups = Repository.getSuperClasses(thiz.getClassName());
// JavaClass[] other_sups = Repository.getSuperClasses(other.getClassName());
//
// if (thiz_sups == null || other_sups == null) {
// return null;
// }
//
// // Waaahh...
// JavaClass[] this_sups = new JavaClass[thiz_sups.length + 1];
// JavaClass[] t_sups = new JavaClass[other_sups.length + 1];
// System.arraycopy(thiz_sups, 0, this_sups, 1, thiz_sups.length);
// System.arraycopy(other_sups, 0, t_sups, 1, other_sups.length);
// this_sups[0] = Repository.lookupClass(thiz.getClassName());
// t_sups[0] = Repository.lookupClass(other.getClassName());
//
// for (int i = 0; i < t_sups.length; i++) {
// for (int j = 0; j < this_sups.length; j++) {
// if (this_sups[j].equals(t_sups[i])) {
// return new ObjectType(this_sups[j].getClassName());
// }
// }
// }
//
// // Huh? Did you ask for Type.OBJECT's superclass??
// return null;
// }
}