DescendingVisitor.java
/*
* 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.bcel.classfile;
import java.util.Objects;
import java.util.Stack;
import java.util.stream.Stream;
/**
* Traverses a JavaClass with another Visitor object 'piggy-backed' that is applied to all components of a JavaClass
* object. I.e. this class supplies the traversal strategy, other classes can make use of it.
*/
public class DescendingVisitor implements Visitor {
private final JavaClass clazz;
private final Visitor visitor;
private final Stack<Object> stack = new Stack<>();
/**
* @param clazz Class to traverse
* @param visitor visitor object to apply to all components
*/
public DescendingVisitor(final JavaClass clazz, final Visitor visitor) {
this.clazz = clazz;
this.visitor = visitor;
}
private <E extends Node> void accept(final E[] node) {
Stream.of(node).forEach(e -> e.accept(this));
}
/**
* @return current object
*/
public Object current() {
return stack.peek();
}
/**
* @return container of current entitity, i.e., predecessor during traversal
*/
public Object predecessor() {
return predecessor(0);
}
/**
* @param level nesting level, i.e., 0 returns the direct predecessor
* @return container of current entitity, i.e., predecessor during traversal
*/
public Object predecessor(final int level) {
final int size = stack.size();
if (size < 2 || level < 0) {
return null;
}
return stack.elementAt(size - (level + 2)); // size - 1 == current
}
/**
* Start traversal.
*/
public void visit() {
clazz.accept(this);
}
/**
* @since 6.0
*/
@Override
public void visitAnnotation(final Annotations annotation) {
stack.push(annotation);
annotation.accept(visitor);
accept(annotation.getAnnotationEntries());
stack.pop();
}
/**
* @since 6.0
*/
@Override
public void visitAnnotationDefault(final AnnotationDefault obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/**
* @since 6.0
*/
@Override
public void visitAnnotationEntry(final AnnotationEntry annotationEntry) {
stack.push(annotationEntry);
annotationEntry.accept(visitor);
stack.pop();
}
/**
* @since 6.0
*/
@Override
public void visitBootstrapMethods(final BootstrapMethods bm) {
stack.push(bm);
bm.accept(visitor);
// BootstrapMethod[] bms = bm.getBootstrapMethods();
// for (int i = 0; i < bms.length; i++)
// {
// bms[i].accept(this);
// }
stack.pop();
}
@Override
public void visitCode(final Code code) {
stack.push(code);
code.accept(visitor);
accept(code.getExceptionTable());
accept(code.getAttributes());
stack.pop();
}
@Override
public void visitCodeException(final CodeException ce) {
stack.push(ce);
ce.accept(visitor);
stack.pop();
}
@Override
public void visitConstantClass(final ConstantClass constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
@Override
public void visitConstantDouble(final ConstantDouble constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
/** @since 6.3 */
@Override
public void visitConstantDynamic(final ConstantDynamic obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
@Override
public void visitConstantFieldref(final ConstantFieldref constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
@Override
public void visitConstantFloat(final ConstantFloat constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
@Override
public void visitConstantInteger(final ConstantInteger constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
@Override
public void visitConstantInterfaceMethodref(final ConstantInterfaceMethodref constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
/**
* @since 6.0
*/
@Override
public void visitConstantInvokeDynamic(final ConstantInvokeDynamic constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
@Override
public void visitConstantLong(final ConstantLong constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
/** @since 6.0 */
@Override
public void visitConstantMethodHandle(final ConstantMethodHandle obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
@Override
public void visitConstantMethodref(final ConstantMethodref constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
/** @since 6.0 */
@Override
public void visitConstantMethodType(final ConstantMethodType obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/** @since 6.1 */
@Override
public void visitConstantModule(final ConstantModule obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
@Override
public void visitConstantNameAndType(final ConstantNameAndType constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
/** @since 6.1 */
@Override
public void visitConstantPackage(final ConstantPackage obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
@Override
public void visitConstantPool(final ConstantPool cp) {
stack.push(cp);
cp.accept(visitor);
Stream.of(cp.getConstantPool()).filter(Objects::nonNull).forEach(e -> e.accept(this));
stack.pop();
}
@Override
public void visitConstantString(final ConstantString constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
@Override
public void visitConstantUtf8(final ConstantUtf8 constant) {
stack.push(constant);
constant.accept(visitor);
stack.pop();
}
@Override
public void visitConstantValue(final ConstantValue cv) {
stack.push(cv);
cv.accept(visitor);
stack.pop();
}
@Override
public void visitDeprecated(final Deprecated attribute) {
stack.push(attribute);
attribute.accept(visitor);
stack.pop();
}
/**
* @since 6.0
*/
@Override
public void visitEnclosingMethod(final EnclosingMethod obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
@Override
public void visitExceptionTable(final ExceptionTable table) {
stack.push(table);
table.accept(visitor);
stack.pop();
}
@Override
public void visitField(final Field field) {
stack.push(field);
field.accept(visitor);
accept(field.getAttributes());
stack.pop();
}
@Override
public void visitInnerClass(final InnerClass inner) {
stack.push(inner);
inner.accept(visitor);
stack.pop();
}
@Override
public void visitInnerClasses(final InnerClasses ic) {
stack.push(ic);
ic.accept(visitor);
accept(ic.getInnerClasses());
stack.pop();
}
@Override
public void visitJavaClass(final JavaClass clazz) {
stack.push(clazz);
clazz.accept(visitor);
accept(clazz.getFields());
accept(clazz.getMethods());
accept(clazz.getAttributes());
clazz.getConstantPool().accept(this);
stack.pop();
}
@Override
public void visitLineNumber(final LineNumber number) {
stack.push(number);
number.accept(visitor);
stack.pop();
}
@Override
public void visitLineNumberTable(final LineNumberTable table) {
stack.push(table);
table.accept(visitor);
accept(table.getLineNumberTable());
stack.pop();
}
@Override
public void visitLocalVariable(final LocalVariable var) {
stack.push(var);
var.accept(visitor);
stack.pop();
}
@Override
public void visitLocalVariableTable(final LocalVariableTable table) {
stack.push(table);
table.accept(visitor);
accept(table.getLocalVariableTable());
stack.pop();
}
/**
* @since 6.0
*/
@Override
public void visitLocalVariableTypeTable(final LocalVariableTypeTable obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
@Override
public void visitMethod(final Method method) {
stack.push(method);
method.accept(visitor);
accept(method.getAttributes());
stack.pop();
}
/**
* @since 6.4.0
*/
@Override
public void visitMethodParameter(final MethodParameter obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/**
* @since 6.0
*/
@Override
public void visitMethodParameters(final MethodParameters obj) {
stack.push(obj);
obj.accept(visitor);
Stream.of(obj.getParameters()).forEach(e -> e.accept(this));
stack.pop();
}
/** @since 6.4.0 */
@Override
public void visitModule(final Module obj) {
stack.push(obj);
obj.accept(visitor);
accept(obj.getRequiresTable());
accept(obj.getExportsTable());
accept(obj.getOpensTable());
accept(obj.getProvidesTable());
stack.pop();
}
/** @since 6.4.0 */
@Override
public void visitModuleExports(final ModuleExports obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/** @since 6.4.0 */
@Override
public void visitModuleMainClass(final ModuleMainClass obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/** @since 6.4.0 */
@Override
public void visitModuleOpens(final ModuleOpens obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/** @since 6.4.0 */
@Override
public void visitModulePackages(final ModulePackages obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/** @since 6.4.0 */
@Override
public void visitModuleProvides(final ModuleProvides obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/** @since 6.4.0 */
@Override
public void visitModuleRequires(final ModuleRequires obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/** @since 6.4.0 */
@Override
public void visitNestHost(final NestHost obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/** @since 6.4.0 */
@Override
public void visitNestMembers(final NestMembers obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/**
* @since 6.0
*/
@Override
public void visitParameterAnnotation(final ParameterAnnotations obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
/** @since 6.0 */
@Override
public void visitParameterAnnotationEntry(final ParameterAnnotationEntry obj) {
stack.push(obj);
obj.accept(visitor);
stack.pop();
}
@Override
public void visitSignature(final Signature attribute) {
stack.push(attribute);
attribute.accept(visitor);
stack.pop();
}
@Override
public void visitSourceFile(final SourceFile attribute) {
stack.push(attribute);
attribute.accept(visitor);
stack.pop();
}
@Override
public void visitStackMap(final StackMap table) {
stack.push(table);
table.accept(visitor);
accept(table.getStackMap());
stack.pop();
}
@Override
public void visitStackMapEntry(final StackMapEntry var) {
stack.push(var);
var.accept(visitor);
accept(var.getTypesOfLocals());
accept(var.getTypesOfStackItems());
stack.pop();
}
/**
* Visits a {@link StackMapType} object.
* @param var object to visit
* @since 6.8.0
*/
@Override
public void visitStackMapType(final StackMapType var) {
stack.push(var);
var.accept(visitor);
stack.pop();
}
@Override
public void visitSynthetic(final Synthetic attribute) {
stack.push(attribute);
attribute.accept(visitor);
stack.pop();
}
@Override
public void visitUnknown(final Unknown attribute) {
stack.push(attribute);
attribute.accept(visitor);
stack.pop();
}
}