/**************************************************************************************
* Copyright (c) The AspectWerkz Team. All rights reserved. *
* http://aspectwerkz.codehaus.org *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the BSD style license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package org.codehaus.aspectwerkz.transform;
import java.util.Set;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.ArrayList;
import org.apache.bcel.generic.InstructionFactory;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.ClassGen;
import org.apache.bcel.generic.Type;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.MethodGen;
import org.apache.bcel.generic.PUSH;
import org.apache.bcel.generic.InstructionConstants;
import org.apache.bcel.generic.FieldGen;
import org.apache.bcel.generic.PUTFIELD;
import org.apache.bcel.generic.PUTSTATIC;
import org.apache.bcel.generic.FieldInstruction;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.GETSTATIC;
import org.apache.bcel.generic.GETFIELD;
import org.apache.bcel.generic.ObjectType;
import org.apache.bcel.Constants;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.classfile.Field;
import org.codehaus.aspectwerkz.metadata.FieldMetaData;
import org.codehaus.aspectwerkz.metadata.BcelMetaDataMaker;
import org.codehaus.aspectwerkz.metadata.ClassMetaData;
import org.codehaus.aspectwerkz.definition.AspectWerkzDefinition;
/**
* Transforms member fields to become "aspect-aware".
*
* @author <a href="mailto:jboner@codehaus.org">Jonas Bon�r</a>
*/
public class AdviseStaticFieldTransformer implements AspectWerkzCodeTransformerComponent {
///CLOVER:OFF
/**
* The definition.
*/
private final AspectWerkzDefinition m_definition;
/**
* Retrieves the weave model.
*/
public AdviseStaticFieldTransformer() {
super();
m_definition = AspectWerkzDefinition.getDefinitionForTransformation();
}
/**
* Transforms the fields.
*
* @param context the transformation context
* @param klass the class set.
*/
public void transformCode(final Context context, final Klass klass) {
final ClassGen cg = klass.getClassGen();
ClassMetaData classMetaData = BcelMetaDataMaker.
createClassMetaData(context.getJavaClass(cg));
if (classFilter(classMetaData, cg)) {
return;
}
Method[] methods = cg.getMethods();
// get the index for the <clinit> method (if there is one)
boolean noClInitMethod = true;
int clinitIndex = -1;
for (int i = 0; i < methods.length; i++) {
if (methods[i].getName().equals("<clinit>")) {
clinitIndex = i;
noClInitMethod = false;
break;
}
}
ConstantPoolGen cpg = cg.getConstantPool();
String className = cg.getClassName();
InstructionFactory factory = new InstructionFactory(cg);
final Set setFieldJoinPoints = new HashSet();
final Set getFieldJoinPoints = new HashSet();
Method clInitMethod = null;
List newMethods = new ArrayList();
boolean isClassAdvised = false;
for (int i = 0; i < methods.length; i++) {
if (methodFilter(methods[i])) {
continue;
}
MethodGen mg = new MethodGen(methods[i], className, cpg);
InstructionList il = mg.getInstructionList();
InstructionHandle ih = il.getStart();
// search for all GETFIELD and GETSTATIC instructions and
// inserts the pre and post advices
while (ih != null) {
Instruction ins = ih.getInstruction();
if (ins instanceof GETFIELD || ins instanceof GETSTATIC) {
FieldInstruction gfIns = (FieldInstruction)ins;
String fieldName = gfIns.getName(cpg);
String signature = gfIns.getFieldType(cpg).toString() + " " + fieldName;
Type joinPointType = TransformationUtil.STATIC_FIELD_GET_JOIN_POINT_TYPE;
String joinPointClass = TransformationUtil.STATIC_FIELD_GET_JOIN_POINT_CLASS;
FieldMetaData fieldMetaData =
BcelMetaDataMaker.createFieldMetaData(gfIns, cpg);
String uuid = getFieldFilter(classMetaData, fieldMetaData);
if (uuid != null) {
String fieldClassName = gfIns.getClassName(cpg);
if (fieldClassName.equals(cg.getClassName())) {
isClassAdvised = true;
// in static context
if (mg.isStatic()) {
insertPreAdvice(il, ih, cg, fieldName, factory, joinPointType);
insertPostAdvice(il, ih.getNext(), cg, fieldName, factory, joinPointType);
// skip the creation of the join point if we
// already have one
if (!getFieldJoinPoints.contains(fieldName)) {
getFieldJoinPoints.add(fieldName);
addStaticJoinPointField(cpg, cg, fieldName, joinPointType);
if (noClInitMethod) {
clInitMethod = createClInitMethodWithStaticJoinPointField(
cpg, cg, fieldName, signature, factory,
joinPointType, joinPointClass, uuid);
}
else {
methods[clinitIndex] = createStaticJoinPointField(
cpg, cg, methods[clinitIndex], fieldName, signature,
factory, joinPointType, joinPointClass, uuid);
}
}
}
}
}
}
else if (ins instanceof PUTFIELD || ins instanceof PUTSTATIC) {
FieldInstruction pfIns = (FieldInstruction)ins;
String fieldName = pfIns.getName(cpg);
String signature = pfIns.getFieldType(cpg).toString() + " " + fieldName;
Type joinPointType = TransformationUtil.STATIC_FIELD_SET_JOIN_POINT_TYPE;
String joinPointClass = TransformationUtil.STATIC_FIELD_SET_JOIN_POINT_CLASS;
FieldMetaData fieldMetaData =
BcelMetaDataMaker.createFieldMetaData(pfIns, cpg);
String uuid = setFieldFilter(classMetaData, fieldMetaData);
if (uuid != null) {
String fieldClassName = pfIns.getClassName(cpg);
if (fieldClassName.equals(cg.getClassName())) {
// in static context
if (mg.isStatic()) {
isClassAdvised = true;
insertPreAdvice(il, ih, cg, fieldName, factory, joinPointType);
insertPostAdvice(il, ih.getNext(), cg, fieldName, factory, joinPointType);
// skip the creation of the join point if we
// already have one
if (!setFieldJoinPoints.contains(fieldName)) {
setFieldJoinPoints.add(fieldName);
addStaticJoinPointField(
cpg, cg,
fieldName,
joinPointType);
if (noClInitMethod) {
clInitMethod = createClInitMethodWithStaticJoinPointField(
cpg, cg, fieldName, signature, factory,
joinPointType, joinPointClass, uuid);
}
else {
methods[clinitIndex] = createStaticJoinPointField(
cpg, cg, methods[clinitIndex], fieldName, signature,
factory, joinPointType, joinPointClass, uuid);
}
}
}
}
}
}
ih = ih.getNext();
}
if (isClassAdvised) {
mg.setMaxStack();
methods[i] = mg.getMethod();
}
}
if (isClassAdvised) {
// if we have transformed methods, create the static class field
if (noClInitMethod && clInitMethod != null) {
addStaticClassField(cpg, cg);
clInitMethod = createStaticClassField(cpg, cg, clInitMethod, factory);
newMethods.add(clInitMethod);
}
else if (!noClInitMethod) {
addStaticClassField(cpg, cg);
methods[clinitIndex] =
createStaticClassField(cpg, cg, methods[clinitIndex], factory);
}
}
// update the old methods
cg.setMethods(methods);
// add the new methods
for (Iterator it = newMethods.iterator(); it.hasNext();) {
Method method = (Method)it.next();
cg.addMethod(method);
}
}
/**
* Creates a static class field.
*
* @param cp the ConstantPoolGen
* @param cg the ClassGen
*/
private void addStaticClassField(final ConstantPoolGen cp,
final ClassGen cg) {
final Field[] fields = cg.getFields();
// check if we already have added this field
for (int i = 0; i < fields.length; i++) {
if (fields[i].getName().equals(TransformationUtil.STATIC_CLASS_FIELD))
return;
}
final FieldGen field = new FieldGen(
Constants.ACC_PRIVATE | Constants.ACC_FINAL | Constants.ACC_STATIC,
new ObjectType("java.lang.Class"),
TransformationUtil.STATIC_CLASS_FIELD,
cp);
cg.addField(field.getField());
}
/**
* Creates a new static class field.
*
* @param cp the ConstantPoolGen
* @param cg the ClassGen
* @param clInit the constructor for the class
* @param factory the objectfactory
* @return the modified clinit method
*/
private static Method createStaticClassField(final ConstantPoolGen cp,
final ClassGen cg,
final Method clInit,
final InstructionFactory factory) {
final String className = cg.getClassName();
final MethodGen mg = new MethodGen(clInit, cg.getClassName(), cp);
final InstructionList il = mg.getInstructionList();
final InstructionHandle ih = il.getStart();
// invoke Class.forName(..)
il.insert(ih, new PUSH(cp, cg.getClassName()));
il.insert(ih, factory.createInvoke(
"java.lang.Class",
"forName",
new ObjectType("java.lang.Class"),
new Type[]{Type.STRING},
Constants.INVOKESTATIC));
// set the result to the static class field
il.insert(ih, factory.createFieldAccess(
className,
TransformationUtil.STATIC_CLASS_FIELD,
new ObjectType("java.lang.Class"),
Constants.PUTSTATIC));
mg.setMaxStack();
mg.setMaxLocals();
return mg.getMethod();
}
/**
* Creates a static join point get field.
*
* @param cp the ConstantPoolGen
* @param cg the ClassGen
* @param fieldName the name of the field
* @param joinPointType the type of the join point
*/
private void addStaticJoinPointField(final ConstantPoolGen cp,
final ClassGen cg,
final String fieldName,
final Type joinPointType) {
final String joinPointPrefix = getJoinPointPrefix(joinPointType);
final StringBuffer joinPoint = getJoinPointName(joinPointPrefix, fieldName);
if (cg.containsField(joinPoint.toString()) != null) {
return;
}
final FieldGen field = new FieldGen(
Constants.ACC_PRIVATE | Constants.ACC_FINAL | Constants.ACC_STATIC,
joinPointType,
joinPoint.toString(),
cp);
cg.addField(field.getField());
}
/**
* Creates a new <clinit> method and creates a join point field.
*
* @param cp the ConstantPoolGen
* @param cg the ClassGen
* @param fieldName the current method name
* @param signature the signature of the method
* @param factory the objectfactory
* @param joinPointType the type of the joinpoint
* @param joinPointClass the class for the joinpoint
* @param uuid the UUID for the weave model
* @return the new method
*/
private Method createClInitMethodWithStaticJoinPointField(
final ConstantPoolGen cp,
final ClassGen cg,
final String fieldName,
final String signature,
final InstructionFactory factory,
final Type joinPointType,
final String joinPointClass,
final String uuid) {
final String className = cg.getClassName();
final String joinPointPrefix = getJoinPointPrefix(joinPointType);
final StringBuffer joinPoint = getJoinPointName(joinPointPrefix, fieldName);
final InstructionList il = new InstructionList();
final MethodGen clInit = new MethodGen(
Constants.ACC_STATIC,
Type.VOID,
Type.NO_ARGS,
new String[]{},
"<clinit>",
className,
il, cp);
// create an new join point
il.append(factory.createNew(joinPointClass));
// load the parameters (uuid, this, field signature)
il.append(InstructionConstants.DUP);
il.append(new PUSH(cp, uuid));
il.append(factory.createFieldAccess(
cg.getClassName(),
TransformationUtil.STATIC_CLASS_FIELD,
new ObjectType("java.lang.Class"),
Constants.GETSTATIC));
il.append(new PUSH(cp, signature));
// invokes the constructor
il.append(factory.createInvoke(
joinPointClass,
"<init>",
Type.VOID,
new Type[]{Type.STRING, new ObjectType("java.lang.Class"), Type.STRING},
Constants.INVOKESPECIAL));
// set the join point to the static field specified
il.append(factory.createFieldAccess(
cg.getClassName(),
joinPoint.toString(),
joinPointType,
Constants.PUTSTATIC));
il.append(factory.createReturn(Type.VOID));
clInit.setMaxLocals();
clInit.setMaxStack();
return clInit.getMethod();
}
/**
* Creates a new static join point field.
*
* @param cp the ConstantPoolGen
* @param cg the ClassGen
* @param clInit the constructor for the class
* @param methodName the current method name
* @param signature the signature of the method
* @param factory the objectfactory
* @param joinPointType the type of the joinpoint
* @param joinPointClass the class for the joinpoint
* @param uuid the UUID for the weave model
* @return the modified clinit method
*/
private Method createStaticJoinPointField(final ConstantPoolGen cp,
final ClassGen cg,
final Method clInit,
final String methodName,
final String signature,
final InstructionFactory factory,
final Type joinPointType,
final String joinPointClass,
final String uuid) {
final String joinPointPrefix = getJoinPointPrefix(joinPointType);
final StringBuffer joinPoint = getJoinPointName(joinPointPrefix, methodName);
final MethodGen mg = new MethodGen(clInit, cg.getClassName(), cp);
final InstructionList il = mg.getInstructionList();
final InstructionHandle ih = il.getStart();
// create an new join point
il.insert(ih, factory.createNew(joinPointClass));
// load the parameters (uuid, this, field signature)
il.insert(ih, InstructionConstants.DUP);
il.insert(ih, new PUSH(cp, uuid));
il.insert(ih, factory.createFieldAccess(
cg.getClassName(),
TransformationUtil.STATIC_CLASS_FIELD,
new ObjectType("java.lang.Class"),
Constants.GETSTATIC));
il.insert(ih, new PUSH(cp, signature));
// invokes the constructor
il.insert(ih, factory.createInvoke(
joinPointClass,
"<init>",
Type.VOID,
new Type[]{Type.STRING, new ObjectType("java.lang.Class"), Type.STRING},
Constants.INVOKESPECIAL));
// set the join point to the static field specified
il.insert(ih, factory.createFieldAccess(
cg.getClassName(),
joinPoint.toString(),
joinPointType,
Constants.PUTSTATIC));
mg.setMaxStack();
mg.setMaxLocals();
return mg.getMethod();
}
/**
* Insert the pre advices for the field.
*
* @param il the instruction list
* @param before the instruction handler to insert it before
* @param cg the ClassGen
* @param fieldName the name of the field
* @param factory the objectfactory
* @param joinPointType the type of the join point
*/
private void insertPreAdvice(final InstructionList il,
final InstructionHandle before,
final ClassGen cg,
final String fieldName,
final InstructionFactory factory,
final Type joinPointType) {
final String joinPointPrefix = getJoinPointPrefix(joinPointType);
final String joinPointClass = getJoinPointClass(joinPointType);
final StringBuffer joinPoint = getJoinPointName(joinPointPrefix, fieldName);
il.insert(before, factory.createFieldAccess(
cg.getClassName(),
joinPoint.toString(),
joinPointType,
Constants.GETSTATIC));
il.insert(before, factory.createInvoke(joinPointClass,
TransformationUtil.FIELD_JOIN_POINT_PRE_EXECUTION_METHOD,
Type.VOID,
Type.NO_ARGS,
Constants.INVOKEVIRTUAL));
}
/**
* Insert the post advices for the field.
*
* @param il the instruction list
* @param before the instruction handle to insert before
* @param cg the ClassGen
* @param fieldName the name of the field
* @param factory the objectfactory
* @param joinPointType the type of the join point
*/
private void insertPostAdvice(final InstructionList il,
final InstructionHandle before,
final ClassGen cg,
final String fieldName,
final InstructionFactory factory,
final Type joinPointType) {
final String joinPointPrefix = getJoinPointPrefix(joinPointType);
final String joinPointClass = getJoinPointClass(joinPointType);
final StringBuffer joinPoint = getJoinPointName(joinPointPrefix, fieldName);
il.insert(before, factory.createFieldAccess(
cg.getClassName(),
joinPoint.toString(),
joinPointType,
Constants.GETSTATIC));
il.insert(before, factory.createInvoke(
joinPointClass,
TransformationUtil.FIELD_JOIN_POINT_POST_EXECUTION_METHOD,
Type.VOID,
Type.NO_ARGS,
Constants.INVOKEVIRTUAL));
}
/**
* Callback method. Is being called before each transformation.
*/
public void sessionStart() {
}
/**
* Callback method. Is being called after each transformation.
*/
public void sessionEnd() {
}
/**
* Callback method. Prints a log/status message at each transformation.
*
* @return a log string
*/
public String verboseMessage() {
return this.getClass().getName();
}
/**
* Filters the classes to be transformed.
*
* @param classMetaData the meta-data for the class
* @param cg the class to filter
* @return boolean true if the method should be filtered away
*/
private boolean classFilter(final ClassMetaData classMetaData, final ClassGen cg) {
if (cg.isInterface()) {
return true;
}
if (!m_definition.inTransformationScope(cg.getClassName())) {
return true;
}
if (m_definition.hasSetFieldPointcut(classMetaData) ||
m_definition.hasGetFieldPointcut(classMetaData)) {
return false;
}
return true;
}
/**
* Filters the methods.
*
* @param method the method to filter
* @return boolean true if the method should be filtered away
*/
private boolean methodFilter(final Method method) {
return method.isNative() || method.isAbstract();
}
/**
* Filters the PUTFIELD's to be transformed.
*
* @param classMetaData the class to filter
* @param fieldMetaData the field to filter
* @return the UUID for the weave model
*/
private String setFieldFilter(final ClassMetaData classMetaData,
final FieldMetaData fieldMetaData) {
if (m_definition.hasSetFieldPointcut(classMetaData, fieldMetaData)) {
return m_definition.getUuid();
}
return null;
}
/**
* Filters the GETFIELD's to be transformed.
*
* @param classMetaData the class to filter
* @param fieldMetaData the field to filter
* @return the UUID for the weave model
*/
private String getFieldFilter(final ClassMetaData classMetaData,
final FieldMetaData fieldMetaData) {
if (m_definition.hasGetFieldPointcut(classMetaData, fieldMetaData)) {
return m_definition.getUuid();
}
return null;
}
/**
* Returns the join point prefix.
*
* @param joinPointType the join point type
* @return the join point prefix
*/
private String getJoinPointPrefix(final Type joinPointType) {
String joinPointPrefix;
if (joinPointType.equals(TransformationUtil.STATIC_FIELD_GET_JOIN_POINT_TYPE)) {
joinPointPrefix = TransformationUtil.STATIC_FIELD_GET_JOIN_POINT_PREFIX;
}
else if (joinPointType.equals(TransformationUtil.STATIC_FIELD_SET_JOIN_POINT_TYPE)) {
joinPointPrefix = TransformationUtil.STATIC_FIELD_SET_JOIN_POINT_PREFIX;
}
else {
throw new RuntimeException("field join point type unknown: " + joinPointType);
}
return joinPointPrefix;
}
/**
* Returns the join point class.
*
* @param joinPointType the join point type
* @return the join point class
*/
private String getJoinPointClass(final Type joinPointType) {
String joinPointClass;
if (joinPointType.equals(TransformationUtil.STATIC_FIELD_GET_JOIN_POINT_TYPE)) {
joinPointClass = TransformationUtil.STATIC_FIELD_GET_JOIN_POINT_CLASS;
}
else if (joinPointType.equals(TransformationUtil.STATIC_FIELD_SET_JOIN_POINT_TYPE)) {
joinPointClass = TransformationUtil.STATIC_FIELD_SET_JOIN_POINT_CLASS;
}
else {
throw new RuntimeException("field join point type unknown: " + joinPointType);
}
return joinPointClass;
}
/**
* Returns the name of the join point.
*
* @param joinPointPrefix the prefix
* @param fieldName the name of the field
* @return the name of the join point
*/
private static StringBuffer getJoinPointName(final String joinPointPrefix,
final String fieldName) {
final StringBuffer joinPoint = new StringBuffer();
joinPoint.append(joinPointPrefix);
joinPoint.append(fieldName);
return joinPoint;
}
///CLOVER:ON
}