JavaClass.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.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;
import org.apache.bcel.Const;
import org.apache.bcel.generic.Type;
import org.apache.bcel.util.BCELComparator;
import org.apache.bcel.util.ClassQueue;
import org.apache.bcel.util.SyntheticRepository;
import org.apache.commons.lang3.ArrayUtils;
/**
* Represents a Java class, i.e., the data structures, constant pool, fields, methods and commands contained in a Java
* .class file. See <a href="https://docs.oracle.com/javase/specs/">JVM specification</a> for details. The intent of
* this class is to represent a parsed or otherwise existing class file. Those interested in programmatically generating
* classes should see the <a href="../generic/ClassGen.html">ClassGen</a> class.
*
* @see org.apache.bcel.generic.ClassGen
*/
public class JavaClass extends AccessFlags implements Cloneable, Node, Comparable<JavaClass> {
/**
* The standard class file extension.
*
* @since 6.7.0
*/
public static final String EXTENSION = ".class";
/**
* Empty array.
*
* @since 6.6.0
*/
public static final JavaClass[] EMPTY_ARRAY = {};
public static final byte HEAP = 1;
public static final byte FILE = 2;
public static final byte ZIP = 3;
private static final boolean debug = Boolean.getBoolean("JavaClass.debug"); // Debugging on/off
private static BCELComparator<JavaClass> bcelComparator = new BCELComparator<JavaClass>() {
@Override
public boolean equals(final JavaClass a, final JavaClass b) {
return a == b || a != null && b != null && Objects.equals(a.getClassName(), b.getClassName());
}
@Override
public int hashCode(final JavaClass o) {
return o != null ? Objects.hashCode(o.getClassName()) : 0;
}
};
/*
* Print debug information depending on 'JavaClass.debug'
*/
static void Debug(final String str) {
if (debug) {
System.out.println(str);
}
}
/**
* @return Comparison strategy object.
*/
public static BCELComparator<JavaClass> getComparator() {
return bcelComparator;
}
private static String indent(final Object obj) {
final StringTokenizer tokenizer = new StringTokenizer(obj.toString(), "\n");
final StringBuilder buf = new StringBuilder();
while (tokenizer.hasMoreTokens()) {
buf.append("\t").append(tokenizer.nextToken()).append("\n");
}
return buf.toString();
}
/**
* @param comparator Comparison strategy object.
*/
public static void setComparator(final BCELComparator<JavaClass> comparator) {
bcelComparator = comparator;
}
private String fileName;
private final String packageName;
private String sourceFileName = "<Unknown>";
private int classNameIndex;
private int superclassNameIndex;
private String className;
private String superclassName;
private int major;
private int minor; // Compiler version
private ConstantPool constantPool; // Constant pool
private int[] interfaces; // implemented interfaces
private String[] interfaceNames;
private Field[] fields; // Fields, i.e., variables of class
private Method[] methods; // methods defined in the class
private Attribute[] attributes; // attributes defined in the class
private AnnotationEntry[] annotations; // annotations defined on the class
private byte source = HEAP; // Generated in memory
private boolean isAnonymous;
private boolean isNested;
private boolean isRecord;
private boolean computedNestedTypeStatus;
private boolean computedRecord;
/**
* In cases where we go ahead and create something, use the default SyntheticRepository, because we don't know any
* better.
*/
private transient org.apache.bcel.util.Repository repository = SyntheticRepository.getInstance();
/**
* Constructor gets all contents as arguments.
*
* @param classNameIndex Class name
* @param superclassNameIndex Superclass name
* @param fileName File name
* @param major Major compiler version
* @param minor Minor compiler version
* @param accessFlags Access rights defined by bit flags
* @param constantPool Array of constants
* @param interfaces Implemented interfaces
* @param fields Class fields
* @param methods Class methods
* @param attributes Class attributes
*/
public JavaClass(final int classNameIndex, final int superclassNameIndex, final String fileName, final int major, final int minor, final int accessFlags,
final ConstantPool constantPool, final int[] interfaces, final Field[] fields, final Method[] methods, final Attribute[] attributes) {
this(classNameIndex, superclassNameIndex, fileName, major, minor, accessFlags, constantPool, interfaces, fields, methods, attributes, HEAP);
}
/**
* Constructor gets all contents as arguments.
*
* @param classNameIndex Index into constant pool referencing a ConstantClass that represents this class.
* @param superclassNameIndex Index into constant pool referencing a ConstantClass that represents this class's
* superclass.
* @param fileName File name
* @param major Major compiler version
* @param minor Minor compiler version
* @param accessFlags Access rights defined by bit flags
* @param constantPool Array of constants
* @param interfaces Implemented interfaces
* @param fields Class fields
* @param methods Class methods
* @param attributes Class attributes
* @param source Read from file or generated in memory?
*/
public JavaClass(final int classNameIndex, final int superclassNameIndex, final String fileName, final int major, final int minor, final int accessFlags,
final ConstantPool constantPool, int[] interfaces, Field[] fields, Method[] methods, Attribute[] attributes, final byte source) {
super(accessFlags);
interfaces = ArrayUtils.nullToEmpty(interfaces);
if (attributes == null) {
attributes = Attribute.EMPTY_ARRAY;
}
if (fields == null) {
fields = Field.EMPTY_ARRAY;
}
if (methods == null) {
methods = Method.EMPTY_ARRAY;
}
this.classNameIndex = classNameIndex;
this.superclassNameIndex = superclassNameIndex;
this.fileName = fileName;
this.major = major;
this.minor = minor;
this.constantPool = constantPool;
this.interfaces = interfaces;
this.fields = fields;
this.methods = methods;
this.attributes = attributes;
this.source = source;
// Get source file name if available
for (final Attribute attribute : attributes) {
if (attribute instanceof SourceFile) {
sourceFileName = ((SourceFile) attribute).getSourceFileName();
break;
}
}
/*
* According to the specification the following entries must be of type 'ConstantClass' but we check that anyway via the
* 'ConstPool.getConstant' method.
*/
className = constantPool.getConstantString(classNameIndex, Const.CONSTANT_Class);
className = Utility.compactClassName(className, false);
final int index = className.lastIndexOf('.');
if (index < 0) {
packageName = "";
} else {
packageName = className.substring(0, index);
}
if (superclassNameIndex > 0) {
// May be zero -> class is java.lang.Object
superclassName = constantPool.getConstantString(superclassNameIndex, Const.CONSTANT_Class);
superclassName = Utility.compactClassName(superclassName, false);
} else {
superclassName = "java.lang.Object";
}
interfaceNames = new String[interfaces.length];
for (int i = 0; i < interfaces.length; i++) {
final String str = constantPool.getConstantString(interfaces[i], Const.CONSTANT_Class);
interfaceNames[i] = Utility.compactClassName(str, false);
}
}
/**
* Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
* I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
*
* @param v Visitor object
*/
@Override
public void accept(final Visitor v) {
v.visitJavaClass(this);
}
/**
* Return the natural ordering of two JavaClasses. This ordering is based on the class name
*
* @since 6.0
*/
@Override
public int compareTo(final JavaClass obj) {
return getClassName().compareTo(obj.getClassName());
}
private void computeIsRecord() {
if (computedRecord) {
return;
}
for (final Attribute attribute : this.attributes) {
if (attribute instanceof Record) {
isRecord = true;
break;
}
}
this.computedRecord = true;
}
private void computeNestedTypeStatus() {
if (computedNestedTypeStatus) {
return;
}
for (final Attribute attribute : this.attributes) {
if (attribute instanceof InnerClasses) {
((InnerClasses) attribute).forEach(innerClass -> {
boolean innerClassAttributeRefersToMe = false;
String innerClassName = constantPool.getConstantString(innerClass.getInnerClassIndex(), Const.CONSTANT_Class);
innerClassName = Utility.compactClassName(innerClassName, false);
if (innerClassName.equals(getClassName())) {
innerClassAttributeRefersToMe = true;
}
if (innerClassAttributeRefersToMe) {
this.isNested = true;
if (innerClass.getInnerNameIndex() == 0) {
this.isAnonymous = true;
}
}
});
}
}
this.computedNestedTypeStatus = true;
}
/**
* @return deep copy of this class
*/
public JavaClass copy() {
try {
final JavaClass c = (JavaClass) clone();
c.constantPool = constantPool.copy();
c.interfaces = interfaces.clone();
c.interfaceNames = interfaceNames.clone();
c.fields = new Field[fields.length];
Arrays.setAll(c.fields, i -> fields[i].copy(c.constantPool));
c.methods = new Method[methods.length];
Arrays.setAll(c.methods, i -> methods[i].copy(c.constantPool));
c.attributes = new Attribute[attributes.length];
Arrays.setAll(c.attributes, i -> attributes[i].copy(c.constantPool));
return c;
} catch (final CloneNotSupportedException e) {
return null;
}
}
/**
* Dump Java class to output stream in binary format.
*
* @param file Output stream
* @throws IOException if an I/O error occurs.
*/
public void dump(final DataOutputStream file) throws IOException {
file.writeInt(Const.JVM_CLASSFILE_MAGIC);
file.writeShort(minor);
file.writeShort(major);
constantPool.dump(file);
file.writeShort(super.getAccessFlags());
file.writeShort(classNameIndex);
file.writeShort(superclassNameIndex);
file.writeShort(interfaces.length);
for (final int interface1 : interfaces) {
file.writeShort(interface1);
}
file.writeShort(fields.length);
for (final Field field : fields) {
field.dump(file);
}
file.writeShort(methods.length);
for (final Method method : methods) {
method.dump(file);
}
if (attributes != null) {
file.writeShort(attributes.length);
for (final Attribute attribute : attributes) {
attribute.dump(file);
}
} else {
file.writeShort(0);
}
file.flush();
}
/**
* Dump class to a file.
*
* @param file Output file
* @throws IOException if an I/O error occurs.
*/
public void dump(final File file) throws IOException {
final String parent = file.getParent();
if (parent != null) {
final File dir = new File(parent);
if (!dir.mkdirs() && !dir.isDirectory()) {
throw new IOException("Could not create the directory " + dir);
}
}
try (DataOutputStream dos = new DataOutputStream(new FileOutputStream(file))) {
dump(dos);
}
}
/**
* Dump Java class to output stream in binary format.
*
* @param file Output stream
* @throws IOException if an I/O error occurs.
*/
public void dump(final OutputStream file) throws IOException {
dump(new DataOutputStream(file));
}
/**
* Dump class to a file named fileName.
*
* @param fileName Output file name
* @throws IOException if an I/O error occurs.
*/
public void dump(final String fileName) throws IOException {
dump(new File(fileName));
}
/**
* Return value as defined by given BCELComparator strategy. By default two JavaClass objects are said to be equal when
* their class names are equal.
*
* @see Object#equals(Object)
*/
@Override
public boolean equals(final Object obj) {
return obj instanceof JavaClass && bcelComparator.equals(this, (JavaClass) obj);
}
/**
* Finds a visible field by name and type in this class and its super classes.
* @param fieldName the field name to find
* @param fieldType the field type to find
* @return field matching given name and type, null if field is not found or not accessible from this class.
* @throws ClassNotFoundException
* @since 6.8.0
*/
public Field findField(final String fieldName, final Type fieldType) throws ClassNotFoundException {
for (final Field field : fields) {
if (field.getName().equals(fieldName)) {
final Type fType = Type.getType(field.getSignature());
/*
* TODO: Check if assignment compatibility is sufficient. What does Sun do?
*/
if (fType.equals(fieldType)) {
return field;
}
}
}
final JavaClass superclass = getSuperClass();
if (superclass != null && !"java.lang.Object".equals(superclass.getClassName())) {
final Field f = superclass.findField(fieldName, fieldType);
if (f != null && (f.isPublic() || f.isProtected() || !f.isPrivate() && packageName.equals(superclass.getPackageName()))) {
return f;
}
}
final JavaClass[] implementedInterfaces = getInterfaces();
if (implementedInterfaces != null) {
for (final JavaClass implementedInterface : implementedInterfaces) {
final Field f = implementedInterface.findField(fieldName, fieldType);
if (f != null) {
return f;
}
}
}
return null;
}
/**
* Gets all interfaces implemented by this JavaClass (transitively).
*
* @throws ClassNotFoundException if any of the class's superclasses or interfaces can't be found.
*/
public JavaClass[] getAllInterfaces() throws ClassNotFoundException {
final ClassQueue queue = new ClassQueue();
final Set<JavaClass> allInterfaces = new TreeSet<>();
queue.enqueue(this);
while (!queue.empty()) {
final JavaClass clazz = queue.dequeue();
final JavaClass souper = clazz.getSuperClass();
final JavaClass[] interfaces = clazz.getInterfaces();
if (clazz.isInterface()) {
allInterfaces.add(clazz);
} else if (souper != null) {
queue.enqueue(souper);
}
for (final JavaClass iface : interfaces) {
queue.enqueue(iface);
}
}
return allInterfaces.toArray(JavaClass.EMPTY_ARRAY);
}
/**
* @return Annotations on the class
* @since 6.0
*/
public AnnotationEntry[] getAnnotationEntries() {
if (annotations == null) {
annotations = AnnotationEntry.createAnnotationEntries(getAttributes());
}
return annotations;
}
/**
* @return Attributes of the class.
*/
public Attribute[] getAttributes() {
return attributes;
}
/**
* @return class in binary format
*/
public byte[] getBytes() {
final ByteArrayOutputStream baos = new ByteArrayOutputStream();
try (DataOutputStream dos = new DataOutputStream(baos)) {
dump(dos);
} catch (final IOException e) {
e.printStackTrace();
}
return baos.toByteArray();
}
/**
* @return Class name.
*/
public String getClassName() {
return className;
}
/**
* @return Class name index.
*/
public int getClassNameIndex() {
return classNameIndex;
}
/**
* @return Constant pool.
*/
public ConstantPool getConstantPool() {
return constantPool;
}
/**
* @return Fields, i.e., variables of the class. Like the JVM spec mandates for the classfile format, these fields are
* those specific to this class, and not those of the superclass or superinterfaces.
*/
public Field[] getFields() {
return fields;
}
/**
* @return File name of class, aka SourceFile attribute value
*/
public String getFileName() {
return fileName;
}
/**
* @return Indices in constant pool of implemented interfaces.
*/
public int[] getInterfaceIndices() {
return interfaces;
}
/**
* @return Names of implemented interfaces.
*/
public String[] getInterfaceNames() {
return interfaceNames;
}
/**
* Gets interfaces directly implemented by this JavaClass.
*
* @throws ClassNotFoundException if any of the class's interfaces can't be found.
*/
public JavaClass[] getInterfaces() throws ClassNotFoundException {
final String[] interfaces = getInterfaceNames();
final JavaClass[] classes = new JavaClass[interfaces.length];
for (int i = 0; i < interfaces.length; i++) {
classes[i] = repository.loadClass(interfaces[i]);
}
return classes;
}
/**
* @return Major number of class file version.
*/
public int getMajor() {
return major;
}
/**
* @return A {@link Method} corresponding to java.lang.reflect.Method if any
*/
public Method getMethod(final java.lang.reflect.Method m) {
for (final Method method : methods) {
if (m.getName().equals(method.getName()) && m.getModifiers() == method.getModifiers() && Type.getSignature(m).equals(method.getSignature())) {
return method;
}
}
return null;
}
/**
* @return Methods of the class.
*/
public Method[] getMethods() {
return methods;
}
/**
* @return Minor number of class file version.
*/
public int getMinor() {
return minor;
}
/**
* @return Package name.
*/
public String getPackageName() {
return packageName;
}
/**
* Gets the ClassRepository which holds its definition. By default this is the same as
* SyntheticRepository.getInstance();
*/
public org.apache.bcel.util.Repository getRepository() {
return repository;
}
/**
* @return returns either HEAP (generated), FILE, or ZIP
*/
public final byte getSource() {
return source;
}
/**
* @return file name where this class was read from
*/
public String getSourceFileName() {
return sourceFileName;
}
/**
* Gets the source file path including the package path.
*
* @return path to original source file of parsed class, relative to original source directory.
* @since 6.7.0
*/
public String getSourceFilePath() {
final StringBuilder outFileName = new StringBuilder();
if (!packageName.isEmpty()) {
outFileName.append(Utility.packageToPath(packageName));
outFileName.append('/');
}
outFileName.append(sourceFileName);
return outFileName.toString();
}
/**
* @return the superclass for this JavaClass object, or null if this is {@link Object}
* @throws ClassNotFoundException if the superclass can't be found
*/
public JavaClass getSuperClass() throws ClassNotFoundException {
if ("java.lang.Object".equals(getClassName())) {
return null;
}
return repository.loadClass(getSuperclassName());
}
/**
* @return list of super classes of this class in ascending order, i.e., java.lang.Object is always the last element
* @throws ClassNotFoundException if any of the superclasses can't be found
*/
public JavaClass[] getSuperClasses() throws ClassNotFoundException {
JavaClass clazz = this;
final List<JavaClass> allSuperClasses = new ArrayList<>();
for (clazz = clazz.getSuperClass(); clazz != null; clazz = clazz.getSuperClass()) {
allSuperClasses.add(clazz);
}
return allSuperClasses.toArray(JavaClass.EMPTY_ARRAY);
}
/**
* returns the super class name of this class. In the case that this class is {@link Object}, it will return itself
* ({@link Object}). This is probably incorrect but isn't fixed at this time to not break existing clients.
*
* @return Superclass name.
*/
public String getSuperclassName() {
return superclassName;
}
/**
* @return Class name index.
*/
public int getSuperclassNameIndex() {
return superclassNameIndex;
}
/**
* Return value as defined by given BCELComparator strategy. By default return the hash code of the class name.
*
* @see Object#hashCode()
*/
@Override
public int hashCode() {
return bcelComparator.hashCode(this);
}
/**
* @return true, if this class is an implementation of interface inter
* @throws ClassNotFoundException if superclasses or superinterfaces of this class can't be found
*/
public boolean implementationOf(final JavaClass inter) throws ClassNotFoundException {
if (!inter.isInterface()) {
throw new IllegalArgumentException(inter.getClassName() + " is no interface");
}
if (this.equals(inter)) {
return true;
}
final JavaClass[] superInterfaces = getAllInterfaces();
for (final JavaClass superInterface : superInterfaces) {
if (superInterface.equals(inter)) {
return true;
}
}
return false;
}
/**
* Equivalent to runtime "instanceof" operator.
*
* @return true if this JavaClass is derived from the super class
* @throws ClassNotFoundException if superclasses or superinterfaces of this object can't be found
*/
public final boolean instanceOf(final JavaClass superclass) throws ClassNotFoundException {
if (this.equals(superclass)) {
return true;
}
for (final JavaClass clazz : getSuperClasses()) {
if (clazz.equals(superclass)) {
return true;
}
}
if (superclass.isInterface()) {
return implementationOf(superclass);
}
return false;
}
/**
* @since 6.0
*/
public final boolean isAnonymous() {
computeNestedTypeStatus();
return this.isAnonymous;
}
public final boolean isClass() {
return (super.getAccessFlags() & Const.ACC_INTERFACE) == 0;
}
/**
* @since 6.0
*/
public final boolean isNested() {
computeNestedTypeStatus();
return this.isNested;
}
/**
* Tests whether this class was declared as a record
*
* @return true if a record attribute is present, false otherwise.
* @since 6.9.0
*/
public boolean isRecord() {
computeIsRecord();
return this.isRecord;
}
public final boolean isSuper() {
return (super.getAccessFlags() & Const.ACC_SUPER) != 0;
}
/**
* @param attributes .
*/
public void setAttributes(final Attribute[] attributes) {
this.attributes = attributes != null ? attributes : Attribute.EMPTY_ARRAY;
}
/**
* @param className .
*/
public void setClassName(final String className) {
this.className = className;
}
/**
* @param classNameIndex .
*/
public void setClassNameIndex(final int classNameIndex) {
this.classNameIndex = classNameIndex;
}
/**
* @param constantPool .
*/
public void setConstantPool(final ConstantPool constantPool) {
this.constantPool = constantPool;
}
/**
* @param fields .
*/
public void setFields(final Field[] fields) {
this.fields = fields != null ? fields : Field.EMPTY_ARRAY;
}
/**
* Sets File name of class, aka SourceFile attribute value
*/
public void setFileName(final String fileName) {
this.fileName = fileName;
}
/**
* @param interfaceNames .
*/
public void setInterfaceNames(final String[] interfaceNames) {
this.interfaceNames = ArrayUtils.nullToEmpty(interfaceNames);
}
/**
* @param interfaces .
*/
public void setInterfaces(final int[] interfaces) {
this.interfaces = ArrayUtils.nullToEmpty(interfaces);
}
/**
* @param major .
*/
public void setMajor(final int major) {
this.major = major;
}
/**
* @param methods .
*/
public void setMethods(final Method[] methods) {
this.methods = methods != null ? methods : Method.EMPTY_ARRAY;
}
/**
* @param minor .
*/
public void setMinor(final int minor) {
this.minor = minor;
}
/**
* Sets the ClassRepository which loaded the JavaClass. Should be called immediately after parsing is done.
*/
public void setRepository(final org.apache.bcel.util.Repository repository) { // TODO make protected?
this.repository = repository;
}
/**
* Sets absolute path to file this class was read from.
*/
public void setSourceFileName(final String sourceFileName) {
this.sourceFileName = sourceFileName;
}
/**
* @param superclassName .
*/
public void setSuperclassName(final String superclassName) {
this.superclassName = superclassName;
}
/**
* @param superclassNameIndex .
*/
public void setSuperclassNameIndex(final int superclassNameIndex) {
this.superclassNameIndex = superclassNameIndex;
}
/**
* @return String representing class contents.
*/
@Override
public String toString() {
String access = Utility.accessToString(super.getAccessFlags(), true);
access = access.isEmpty() ? "" : access + " ";
final StringBuilder buf = new StringBuilder(128);
buf.append(access).append(Utility.classOrInterface(super.getAccessFlags())).append(" ").append(className).append(" extends ")
.append(Utility.compactClassName(superclassName, false)).append('\n');
final int size = interfaces.length;
if (size > 0) {
buf.append("implements\t\t");
for (int i = 0; i < size; i++) {
buf.append(interfaceNames[i]);
if (i < size - 1) {
buf.append(", ");
}
}
buf.append('\n');
}
buf.append("file name\t\t").append(fileName).append('\n');
buf.append("compiled from\t\t").append(sourceFileName).append('\n');
buf.append("compiler version\t").append(major).append(".").append(minor).append('\n');
buf.append("access flags\t\t").append(super.getAccessFlags()).append('\n');
buf.append("constant pool\t\t").append(constantPool.getLength()).append(" entries\n");
buf.append("ACC_SUPER flag\t\t").append(isSuper()).append("\n");
if (attributes.length > 0) {
buf.append("\nAttribute(s):\n");
for (final Attribute attribute : attributes) {
buf.append(indent(attribute));
}
}
final AnnotationEntry[] annotations = getAnnotationEntries();
if (annotations != null && annotations.length > 0) {
buf.append("\nAnnotation(s):\n");
for (final AnnotationEntry annotation : annotations) {
buf.append(indent(annotation));
}
}
if (fields.length > 0) {
buf.append("\n").append(fields.length).append(" fields:\n");
for (final Field field : fields) {
buf.append("\t").append(field).append('\n');
}
}
if (methods.length > 0) {
buf.append("\n").append(methods.length).append(" methods:\n");
for (final Method method : methods) {
buf.append("\t").append(method).append('\n');
}
}
return buf.toString();
}
}