javassist.CtClass Maven / Gradle / Ivy
/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package javassist;
import java.io.BufferedOutputStream;
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.net.URL;
import java.security.ProtectionDomain;
import java.util.Collection;
import javassist.bytecode.ClassFile;
import javassist.bytecode.Descriptor;
import javassist.bytecode.Opcode;
import javassist.bytecode.SignatureAttribute;
import javassist.expr.ExprEditor;
/* Note:
*
* This class is an abstract class and several methods just return null
* or throw an exception. Those methods are overridden in subclasses
* of this class. Read the source code of CtClassType if you are
* interested in the implementation of Javassist.
*
* Subclasses of CtClass are CtClassType, CtPrimitiveType, and CtArray.
*/
/**
* An instance of CtClass represents a class.
* It is obtained from ClassPool.
*
* @see ClassPool#get(String)
*/
public abstract class CtClass {
protected String qualifiedName;
/**
* If the value of this field is not null, then all class
* files modified by Javassist are saved under the directory
* specified by this variable. For example, if the value is
* "./debug", then all class files are saved
* there. The directory name must not end with a directory
* separator such as /.
*
* The default value is null.
*
* @see #debugWriteFile(String)
* @since 3.16
*/
public static String debugDump = null;
/**
* The version number of this release.
*/
public static final String version = "3.18.0-GA";
/**
* Prints the version number and the copyright notice.
*
*
The following command invokes this method:
*
*
java -jar javassist.jar
*/
public static void main(String[] args) {
System.out.println("Javassist version " + CtClass.version);
System.out.println("Copyright (C) 1999-2013 Shigeru Chiba."
+ " All Rights Reserved.");
}
static final String javaLangObject = "java.lang.Object";
/**
* The CtClass object representing
* the boolean type.
*/
public static CtClass booleanType;
/**
* The CtClass object representing
* the char type.
*/
public static CtClass charType;
/**
* The CtClass object representing
* the byte type.
*/
public static CtClass byteType;
/**
* The CtClass object representing
* the short type.
*/
public static CtClass shortType;
/**
* The CtClass object representing
* the int type.
*/
public static CtClass intType;
/**
* The CtClass object representing
* the long type.
*/
public static CtClass longType;
/**
* The CtClass object representing
* the float type.
*/
public static CtClass floatType;
/**
* The CtClass object representing
* the double type.
*/
public static CtClass doubleType;
/**
* The CtClass object representing
* the void type.
*/
public static CtClass voidType;
static CtClass[] primitiveTypes;
static {
primitiveTypes = new CtClass[9];
booleanType =
new CtPrimitiveType("boolean", 'Z', "java.lang.Boolean",
"booleanValue", "()Z", Opcode.IRETURN,
Opcode.T_BOOLEAN, 1);
primitiveTypes[0] = booleanType;
charType = new CtPrimitiveType("char", 'C', "java.lang.Character",
"charValue", "()C", Opcode.IRETURN,
Opcode.T_CHAR, 1);
primitiveTypes[1] = charType;
byteType = new CtPrimitiveType("byte", 'B', "java.lang.Byte",
"byteValue", "()B", Opcode.IRETURN,
Opcode.T_BYTE, 1);
primitiveTypes[2] = byteType;
shortType = new CtPrimitiveType("short", 'S', "java.lang.Short",
"shortValue", "()S", Opcode.IRETURN,
Opcode.T_SHORT, 1);
primitiveTypes[3] = shortType;
intType = new CtPrimitiveType("int", 'I', "java.lang.Integer",
"intValue", "()I", Opcode.IRETURN,
Opcode.T_INT, 1);
primitiveTypes[4] = intType;
longType = new CtPrimitiveType("long", 'J', "java.lang.Long",
"longValue", "()J", Opcode.LRETURN,
Opcode.T_LONG, 2);
primitiveTypes[5] = longType;
floatType = new CtPrimitiveType("float", 'F', "java.lang.Float",
"floatValue", "()F", Opcode.FRETURN,
Opcode.T_FLOAT, 1);
primitiveTypes[6] = floatType;
doubleType = new CtPrimitiveType("double", 'D', "java.lang.Double",
"doubleValue", "()D", Opcode.DRETURN,
Opcode.T_DOUBLE, 2);
primitiveTypes[7] = doubleType;
voidType = new CtPrimitiveType("void", 'V', "java.lang.Void",
null, null, Opcode.RETURN, 0, 0);
primitiveTypes[8] = voidType;
}
protected CtClass(String name) {
qualifiedName = name;
}
/**
* Converts the object to a string.
*/
public String toString() {
StringBuffer buf = new StringBuffer(getClass().getName());
buf.append("@");
buf.append(Integer.toHexString(hashCode()));
buf.append("[");
extendToString(buf);
buf.append("]");
return buf.toString();
}
/**
* Implemented in subclasses to add to the {@link #toString()} result.
* Subclasses should put a space before each token added to the buffer.
*/
protected void extendToString(StringBuffer buffer) {
buffer.append(getName());
}
/**
* Returns a ClassPool for this class.
*/
public ClassPool getClassPool() { return null; }
/**
* Returns a class file for this class.
*
* This method is not available if isFrozen()
* is true.
*/
public ClassFile getClassFile() {
checkModify();
return getClassFile2();
}
/**
* Returns a class file for this class (read only).
* Normal applications do not need calling this method. Use
* getClassFile().
*
*
The ClassFile object obtained by this method
* is read only. Changes to this object might not be reflected
* on a class file generated by toBytecode(),
* toClass(), etc.
*
*
This method is available even if isFrozen()
* is true. However, if the class is frozen, it might be also
* pruned.
*
* @see CtClass#getClassFile()
* @see CtClass#isFrozen()
* @see CtClass#prune()
*/
public ClassFile getClassFile2() { return null; }
/**
* Undocumented method. Do not use; internal-use only.
*/
public javassist.compiler.AccessorMaker getAccessorMaker() {
return null;
}
/**
* Returns the uniform resource locator (URL) of the class file.
*/
public URL getURL() throws NotFoundException {
throw new NotFoundException(getName());
}
/**
* Returns true if the definition of the class has been modified.
*/
public boolean isModified() { return false; }
/**
* Returns true if the class has been loaded or written out
* and thus it cannot be modified any more.
*
* @see #defrost()
* @see #detach()
*/
public boolean isFrozen() { return true; }
/**
* Makes the class frozen.
*
* @see #isFrozen()
* @see #defrost()
* @since 3.6
*/
public void freeze() {}
/* Note: this method is overridden by CtClassType
*/
void checkModify() throws RuntimeException {
if (isFrozen())
throw new RuntimeException(getName() + " class is frozen");
// isModified() must return true after this method is invoked.
}
/**
* Defrosts the class so that the class can be modified again.
*
*
To avoid changes that will be never reflected,
* the class is frozen to be unmodifiable if it is loaded or
* written out. This method should be called only in a case
* that the class will be reloaded or written out later again.
*
*
If defrost() will be called later, pruning
* must be disallowed in advance.
*
* @see #isFrozen()
* @see #stopPruning(boolean)
* @see #detach()
*/
public void defrost() {
throw new RuntimeException("cannot defrost " + getName());
}
/**
* Returns true if this object represents a primitive
* Java type: boolean, byte, char, short, int, long, float, double,
* or void.
*/
public boolean isPrimitive() { return false; }
/**
* Returns true if this object represents an array type.
*/
public boolean isArray() {
return false;
}
/**
* If this object represents an array, this method returns the component
* type of the array. Otherwise, it returns null.
*/
public CtClass getComponentType() throws NotFoundException {
return null;
}
/**
* Returns true if this class extends or implements
* clazz. It also returns true if
* this class is the same as clazz.
*/
public boolean subtypeOf(CtClass clazz) throws NotFoundException {
return this == clazz || getName().equals(clazz.getName());
}
/**
* Obtains the fully-qualified name of the class.
*/
public String getName() { return qualifiedName; }
/**
* Obtains the not-qualified class name.
*/
public final String getSimpleName() {
String qname = qualifiedName;
int index = qname.lastIndexOf('.');
if (index < 0)
return qname;
else
return qname.substring(index + 1);
}
/**
* Obtains the package name. It may be null.
*/
public final String getPackageName() {
String qname = qualifiedName;
int index = qname.lastIndexOf('.');
if (index < 0)
return null;
else
return qname.substring(0, index);
}
/**
* Sets the class name
*
* @param name fully-qualified name
*/
public void setName(String name) {
checkModify();
if (name != null)
qualifiedName = name;
}
/**
* Returns the generic signature of the class.
*
*
The generics of Java is implemented by the erasure technique.
* After compilation, all type parameters are dropped off from the
* main part of a class file. However, for reflection, the type
* parameters are encoded into generic signatures and attached
* to a class file.
*
* @return null if the generic signature is not included.
* @see javassist.bytecode.SignatureAttribute#toClassSignature(String)
* @see CtMember#getGenericSignature()
* @since 3.17
*/
public String getGenericSignature() { return null; }
/**
* Sets the generic signature of the class.
*
*
The generics of Java is implemented by the erasure technique.
* After compilation, all type parameters are dropped off from the
* main part of a class file. However, for reflection, the type
* parameters must be encoded into generic signatures and attached
* to a class file.
*
*
For example,
*
*
class List {
* T value;
* T get() { return value; }
* void set(T v) { value = v; }
* }
*
*
* this class is generated by the following code:
*
*
* ClassPool pool = ClassPool.getDefault();
* CtClass cc = pool.makeClass("List");
* CtClass objectClass = pool.get(CtClass.javaLangObject);
* ClassSignature cs = new ClassSignature(
* new TypeParameter[] { new TypeParameter("T") });
* cc.setGenericSignature(cs.encode()); // <T:Ljava/lang/Object;>Ljava/lang/Object;
*
* CtField f = new CtField(objClass, "value", cc);
* TypeVariable tvar = new TypeVariable("T");
* f.setGenericSignature(tvar.encode()); // TT;
* cc.addField(f);
*
* CtMethod m = CtNewMethod.make("public Object get(){return value;}", cc);
* MethodSignature ms = new MethodSignature(null, null, tvar, null);
* m.setGenericSignature(ms.encode()); // ()TT;
* cc.addMethod(m);
*
* CtMethod m2 = CtNewMethod.make("public void set(Object v){value = v;}", cc);
* MethodSignature ms2 = new MethodSignature(null, new Type[] { tvar },
* new BaseType("void"), null);
* m2.setGenericSignature(ms2.encode()); // (TT;)V;
* cc.addMethod(m2);
*
* cc.writeFile();
*
*
* The generated class file is equivalent to the following:
*
*
class List {
* Object value;
* Object get() { return value; }
* void set(Object v) { value = v; }
* }
*
* but it includes generic signatures for the class, the field,
* and the methods so that the type variable T can be
* accessible through reflection.
*
* @param sig a generic signature.
* @see javassist.bytecode.SignatureAttribute.ClassSignature#encode()
* @see javassist.bytecode.SignatureAttribute.MethodSignature#encode()
* @see CtMember#setGenericSignature(String)
* @since 3.17
*/
public void setGenericSignature(String sig) { checkModify(); }
/**
* Substitutes newName for all occurrences of a class
* name oldName in the class file.
*
* @param oldName replaced class name
* @param newName substituted class name
*/
public void replaceClassName(String oldName, String newName) {
checkModify();
}
/**
* Changes class names appearing in the class file according to the
* given map.
*
*
All the class names appearing in the class file are tested
* with map to determine whether each class name is
* replaced or not. Thus this method can be used for collecting
* all the class names in the class file. To do that, first define
* a subclass of ClassMap so that get()
* records all the given parameters. Then, make an instance of
* that subclass as an empty hash-table. Finally, pass that instance
* to this method. After this method finishes, that instance would
* contain all the class names appearing in the class file.
*
* @param map the hashtable associating replaced class names
* with substituted names.
*/
public void replaceClassName(ClassMap map) {
checkModify();
}
/**
* Returns a collection of the names of all the classes
* referenced in this class.
* That collection includes the name of this class.
*
*
This method may return null.
*
* @return a Collection<String> object.
*/
public synchronized Collection getRefClasses() {
ClassFile cf = getClassFile2();
if (cf != null) {
ClassMap cm = new ClassMap() {
public void put(String oldname, String newname) {
put0(oldname, newname);
}
public Object get(Object jvmClassName) {
String n = toJavaName((String)jvmClassName);
put0(n, n);
return null;
}
public void fix(String name) {}
};
cf.getRefClasses(cm);
return cm.values();
}
else
return null;
}
/**
* Determines whether this object represents a class or an interface.
* It returns true if this object represents an interface.
*/
public boolean isInterface() {
return false;
}
/**
* Determines whether this object represents an annotation type.
* It returns true if this object represents an annotation type.
*
* @since 3.2
*/
public boolean isAnnotation() {
return false;
}
/**
* Determines whether this object represents an enum.
* It returns true if this object represents an enum.
*
* @since 3.2
*/
public boolean isEnum() {
return false;
}
/**
* Returns the modifiers for this class, encoded in an integer.
* For decoding, use javassist.Modifier.
*
*
If the class is a static nested class (a.k.a. static inner class),
* the returned modifiers include Modifier.STATIC.
*
* @see Modifier
*/
public int getModifiers() {
return 0;
}
/**
* Returns true if the class has the specified annotation class.
*
* @param clz the annotation class.
* @return true if the annotation is found, otherwise false.
* @since 3.11
*/
public boolean hasAnnotation(Class clz) {
return false;
}
/**
* Returns the annotation if the class has the specified annotation class.
* For example, if an annotation @Author is associated
* with this class, an Author object is returned.
* The member values can be obtained by calling methods on
* the Author object.
*
* @param clz the annotation class.
* @return the annotation if found, otherwise null.
* @since 3.11
*/
public Object getAnnotation(Class clz) throws ClassNotFoundException {
return null;
}
/**
* Returns the annotations associated with this class.
* For example, if an annotation @Author is associated
* with this class, the returned array contains an Author
* object. The member values can be obtained by calling methods on
* the Author object.
*
* @return an array of annotation-type objects.
* @see CtMember#getAnnotations()
* @since 3.1
*/
public Object[] getAnnotations() throws ClassNotFoundException {
return new Object[0];
}
/**
* Returns the annotations associated with this class.
* This method is equivalent to getAnnotations()
* except that, if any annotations are not on the classpath,
* they are not included in the returned array.
*
* @return an array of annotation-type objects.
* @see #getAnnotations()
* @see CtMember#getAvailableAnnotations()
* @since 3.3
*/
public Object[] getAvailableAnnotations(){
return new Object[0];
}
/**
* Returns an array of nested classes declared in the class.
* Nested classes are inner classes, anonymous classes, local classes,
* and static nested classes. This simply calls getNestedClasses().
*
* @see #getNestedClasses()
* @since 3.15
*/
public CtClass[] getDeclaredClasses() throws NotFoundException {
return getNestedClasses();
}
/**
* Returns an array of nested classes declared in the class.
* Nested classes are inner classes, anonymous classes, local classes,
* and static nested classes.
*
* @since 3.2
*/
public CtClass[] getNestedClasses() throws NotFoundException {
return new CtClass[0];
}
/**
* Sets the modifiers.
*
*
If the class is a nested class, this method also modifies
* the class declaring that nested class (i.e. the enclosing
* class is modified).
*
* @param mod modifiers encoded by
* javassist.Modifier
* @see Modifier
*/
public void setModifiers(int mod) {
checkModify();
}
/**
* Determines whether the class directly or indirectly extends
* the given class. If this class extends a class A and
* the class A extends a class B, then subclassof(B) returns true.
*
*
This method returns true if the given class is identical to
* the class represented by this object.
*/
public boolean subclassOf(CtClass superclass) {
return false;
}
/**
* Obtains the class object representing the superclass of the
* class.
* It returns null if this object represents the
* java.lang.Object class and thus it does not have
* the super class.
*
*
If this object represents an interface, this method
* always returns the java.lang.Object class.
* To obtain the super interfaces
* extended by that interface, call getInterfaces().
*/
public CtClass getSuperclass() throws NotFoundException {
return null;
}
/**
* Changes a super class unless this object represents an interface.
* The new super class must be compatible with the old one; for example,
* it should inherit from the old super class.
*
*
If this object represents an interface, this method is equivalent
* to addInterface(); it appends clazz to
* the list of the super interfaces extended by that interface.
* Note that an interface can extend multiple super interfaces.
*
* @see #replaceClassName(String, String)
* @see #replaceClassName(ClassMap)
*/
public void setSuperclass(CtClass clazz) throws CannotCompileException {
checkModify();
}
/**
* Obtains the class objects representing the interfaces implemented
* by the class or, if this object represents an interface, the interfaces
* extended by that interface.
*/
public CtClass[] getInterfaces() throws NotFoundException {
return new CtClass[0];
}
/**
* Sets implemented interfaces. If this object represents an interface,
* this method sets the interfaces extended by that interface.
*
* @param list a list of the CtClass objects
* representing interfaces, or
* null if the class implements
* no interfaces.
*/
public void setInterfaces(CtClass[] list) {
checkModify();
}
/**
* Adds an interface.
*
* @param anInterface the added interface.
*/
public void addInterface(CtClass anInterface) {
checkModify();
}
/**
* If this class is a member class or interface of another class,
* then the class enclosing this class is returned.
*
* @return null if this class is a top-level class or an anonymous class.
*/
public CtClass getDeclaringClass() throws NotFoundException {
return null;
}
/**
* Returns the immediately enclosing method of this class.
* This method works only with JDK 1.5 or later.
*
* @return null if this class is not a local class or an anonymous
* class.
*/
public CtMethod getEnclosingMethod() throws NotFoundException {
return null;
}
/**
* Makes a new public nested class. If this method is called,
* the CtClass, which encloses the nested class, is modified
* since a class file includes a list of nested classes.
*
*
The current implementation only supports a static nested class.
* isStatic must be true.
*
* @param name the simple name of the nested class.
* @param isStatic true if the nested class is static.
*/
public CtClass makeNestedClass(String name, boolean isStatic) {
throw new RuntimeException(getName() + " is not a class");
}
/**
* Returns an array containing CtField objects
* representing all the non-private fields of the class.
* That array includes non-private fields inherited from the
* superclasses.
*/
public CtField[] getFields() { return new CtField[0]; }
/**
* Returns the field with the specified name. The returned field
* may be a private field declared in a super class or interface.
*/
public CtField getField(String name) throws NotFoundException {
return getField(name, null);
}
/**
* Returns the field with the specified name and type. The returned field
* may be a private field declared in a super class or interface.
* Unlike Java, the JVM allows a class to have
* multiple fields with the same name but different types.
*
* @param name the field name.
* @param desc the type descriptor of the field. It is available by
* {@link CtField#getSignature()}.
* @see CtField#getSignature()
*/
public CtField getField(String name, String desc) throws NotFoundException {
throw new NotFoundException(name);
}
/**
* @return null if the specified field is not found.
*/
CtField getField2(String name, String desc) { return null; }
/**
* Gets all the fields declared in the class. The inherited fields
* are not included.
*
*
Note: the result does not include inherited fields.
*/
public CtField[] getDeclaredFields() { return new CtField[0]; }
/**
* Retrieves the field with the specified name among the fields
* declared in the class.
*
*
Note: this method does not search the super classes.
*/
public CtField getDeclaredField(String name) throws NotFoundException {
throw new NotFoundException(name);
}
/**
* Retrieves the field with the specified name and type among the fields
* declared in the class. Unlike Java, the JVM allows a class to have
* multiple fields with the same name but different types.
*
*
Note: this method does not search the super classes.
*
* @param name the field name.
* @param desc the type descriptor of the field. It is available by
* {@link CtField#getSignature()}.
* @see CtField#getSignature()
*/
public CtField getDeclaredField(String name, String desc) throws NotFoundException {
throw new NotFoundException(name);
}
/**
* Gets all the constructors and methods declared in the class.
*/
public CtBehavior[] getDeclaredBehaviors() {
return new CtBehavior[0];
}
/**
* Returns an array containing CtConstructor objects
* representing all the non-private constructors of the class.
*/
public CtConstructor[] getConstructors() {
return new CtConstructor[0];
}
/**
* Returns the constructor with the given signature,
* which is represented by a character string
* called method descriptor.
* For details of the method descriptor, see the JVM specification
* or javassist.bytecode.Descriptor.
*
* @param desc method descriptor
* @see javassist.bytecode.Descriptor
*/
public CtConstructor getConstructor(String desc)
throws NotFoundException
{
throw new NotFoundException("no such constructor");
}
/**
* Gets all the constructors declared in the class.
*
* @see javassist.CtConstructor
*/
public CtConstructor[] getDeclaredConstructors() {
return new CtConstructor[0];
}
/**
* Returns a constructor receiving the specified parameters.
*
* @param params parameter types.
*/
public CtConstructor getDeclaredConstructor(CtClass[] params)
throws NotFoundException
{
String desc = Descriptor.ofConstructor(params);
return getConstructor(desc);
}
/**
* Gets the class initializer (static constructor)
* declared in the class.
* This method returns null if
* no class initializer is not declared.
*
* @see #makeClassInitializer()
* @see javassist.CtConstructor
*/
public CtConstructor getClassInitializer() {
return null;
}
/**
* Returns an array containing CtMethod objects
* representing all the non-private methods of the class.
* That array includes non-private methods inherited from the
* superclasses.
*/
public CtMethod[] getMethods() {
return new CtMethod[0];
}
/**
* Returns the method with the given name and signature.
* The returned method may be declared in a super class.
* The method signature is represented by a character string
* called method descriptor,
* which is defined in the JVM specification.
*
* @param name method name
* @param desc method descriptor
* @see CtBehavior#getSignature()
* @see javassist.bytecode.Descriptor
*/
public CtMethod getMethod(String name, String desc)
throws NotFoundException
{
throw new NotFoundException(name);
}
/**
* Gets all methods declared in the class. The inherited methods
* are not included.
*
* @see javassist.CtMethod
*/
public CtMethod[] getDeclaredMethods() {
return new CtMethod[0];
}
/**
* Retrieves the method with the specified name and parameter types
* among the methods declared in the class.
*
*
Note: this method does not search the superclasses.
*
* @param name method name
* @param params parameter types
* @see javassist.CtMethod
*/
public CtMethod getDeclaredMethod(String name, CtClass[] params)
throws NotFoundException
{
throw new NotFoundException(name);
}
/**
* Retrieves the method with the specified name among the methods
* declared in the class. If there are multiple methods with
* the specified name, then this method returns one of them.
*
*
Note: this method does not search the superclasses.
*
* @see javassist.CtMethod
*/
public CtMethod getDeclaredMethod(String name) throws NotFoundException {
throw new NotFoundException(name);
}
/**
* Makes an empty class initializer (static constructor).
* If the class already includes a class initializer,
* this method returns it.
*
* @see #getClassInitializer()
*/
public CtConstructor makeClassInitializer()
throws CannotCompileException
{
throw new CannotCompileException("not a class");
}
/**
* Adds a constructor. To add a class initializer (static constructor),
* call makeClassInitializer().
*
* @see #makeClassInitializer()
*/
public void addConstructor(CtConstructor c)
throws CannotCompileException
{
checkModify();
}
/**
* Removes a constructor declared in this class.
*
* @param c removed constructor.
* @throws NotFoundException if the constructor is not found.
*/
public void removeConstructor(CtConstructor c) throws NotFoundException {
checkModify();
}
/**
* Adds a method.
*/
public void addMethod(CtMethod m) throws CannotCompileException {
checkModify();
}
/**
* Removes a method declared in this class.
*
* @param m removed method.
* @throws NotFoundException if the method is not found.
*/
public void removeMethod(CtMethod m) throws NotFoundException {
checkModify();
}
/**
* Adds a field.
*
*
The CtField belonging to another
* CtClass cannot be directly added to this class.
* Only a field created for this class can be added.
*
* @see javassist.CtField#CtField(CtField,CtClass)
*/
public void addField(CtField f) throws CannotCompileException {
addField(f, (CtField.Initializer)null);
}
/**
* Adds a field with an initial value.
*
*
The CtField belonging to another
* CtClass cannot be directly added to this class.
* Only a field created for this class can be added.
*
*
The initial value is given as an expression written in Java.
* Any regular Java expression can be used for specifying the initial
* value. The followings are examples.
*
*
* cc.addField(f, "0") // the initial value is 0.
* cc.addField(f, "i + 1") // i + 1.
* cc.addField(f, "new Point()"); // a Point object.
*
*
* Here, the type of variable cc is CtClass.
* The type of f is CtField.
*
*
Note: do not change the modifier of the field
* (in particular, do not add or remove static
* to/from the modifier)
* after it is added to the class by addField().
*
* @param init an expression for the initial value.
*
* @see javassist.CtField.Initializer#byExpr(String)
* @see javassist.CtField#CtField(CtField,CtClass)
*/
public void addField(CtField f, String init)
throws CannotCompileException
{
checkModify();
}
/**
* Adds a field with an initial value.
*
*
The CtField belonging to another
* CtClass cannot be directly added to this class.
* Only a field created for this class can be added.
*
*
For example,
*
*
* CtClass cc = ...;
* addField(new CtField(CtClass.intType, "i", cc),
* CtField.Initializer.constant(1));
*
*
* This code adds an int field named "i". The
* initial value of this field is 1.
*
* @param init specifies the initial value of the field.
*
* @see javassist.CtField#CtField(CtField,CtClass)
*/
public void addField(CtField f, CtField.Initializer init)
throws CannotCompileException
{
checkModify();
}
/**
* Removes a field declared in this class.
*
* @param f removed field.
* @throws NotFoundException if the field is not found.
*/
public void removeField(CtField f) throws NotFoundException {
checkModify();
}
/**
* Obtains an attribute with the given name.
* If that attribute is not found in the class file, this
* method returns null.
*
*
This is a convenient method mainly for obtaining
* a user-defined attribute. For dealing with attributes, see the
* javassist.bytecode package. For example, the following
* expression returns all the attributes of a class file.
*
*
* getClassFile().getAttributes()
*
*
* @param name attribute name
* @see javassist.bytecode.AttributeInfo
*/
public byte[] getAttribute(String name) {
return null;
}
/**
* Adds a named attribute.
* An arbitrary data (smaller than 64Kb) can be saved in the class
* file. Some attribute name are reserved by the JVM.
* The attributes with the non-reserved names are ignored when a
* class file is loaded into the JVM.
* If there is already an attribute with
* the same name, this method substitutes the new one for it.
*
* This is a convenient method mainly for adding
* a user-defined attribute. For dealing with attributes, see the
* javassist.bytecode package. For example, the following
* expression adds an attribute info to a class file.
*
*
* getClassFile().addAttribute(info)
*
*
* @param name attribute name
* @param data attribute value
* @see javassist.bytecode.AttributeInfo
*/
public void setAttribute(String name, byte[] data) {
checkModify();
}
/**
* Applies the given converter to all methods and constructors
* declared in the class. This method calls instrument()
* on every CtMethod and CtConstructor object
* in the class.
*
* @param converter specifies how to modify.
*/
public void instrument(CodeConverter converter)
throws CannotCompileException
{
checkModify();
}
/**
* Modifies the bodies of all methods and constructors
* declared in the class. This method calls instrument()
* on every CtMethod and CtConstructor object
* in the class.
*
* @param editor specifies how to modify.
*/
public void instrument(ExprEditor editor)
throws CannotCompileException
{
checkModify();
}
/**
* Converts this class to a java.lang.Class object.
* Once this method is called, further modifications are not
* allowed any more.
* To load the class, this method uses the context class loader
* of the current thread. If the program is running on some application
* server, the context class loader might be inappropriate to load the
* class.
*
* This method is provided for convenience. If you need more
* complex functionality, you should write your own class loader.
*
*
Note: this method calls toClass()
* in ClassPool.
*
*
Warining: A Class object returned by this method may not
* work with a security manager or a signed jar file because a
* protection domain is not specified.
*
* @see #toClass(java.lang.ClassLoader,ProtectionDomain)
* @see ClassPool#toClass(CtClass)
*/
public Class toClass() throws CannotCompileException {
return getClassPool().toClass(this);
}
/**
* Converts this class to a java.lang.Class object.
* Once this method is called, further modifications are not allowed
* any more.
*
*
The class file represented by this CtClass is
* loaded by the given class loader to construct a
* java.lang.Class object. Since a private method
* on the class loader is invoked through the reflection API,
* the caller must have permissions to do that.
*
*
An easy way to obtain ProtectionDomain object is
* to call getProtectionDomain()
* in java.lang.Class. It returns the domain that
* the class belongs to.
*
*
This method is provided for convenience. If you need more
* complex functionality, you should write your own class loader.
*
*
Note: this method calls toClass()
* in ClassPool.
*
* @param loader the class loader used to load this class.
* If it is null, the class loader returned by
* {@link ClassPool#getClassLoader()} is used.
* @param domain the protection domain that the class belongs to.
* If it is null, the default domain created
* by java.lang.ClassLoader is used.
* @see ClassPool#toClass(CtClass,java.lang.ClassLoader)
* @since 3.3
*/
public Class toClass(ClassLoader loader, ProtectionDomain domain)
throws CannotCompileException
{
ClassPool cp = getClassPool();
if (loader == null)
loader = cp.getClassLoader();
return cp.toClass(this, loader, domain);
}
/**
* Converts this class to a java.lang.Class object.
*
*
Warining: A Class object returned by this method may not
* work with a security manager or a signed jar file because a
* protection domain is not specified.
*
* @deprecated Replaced by {@link #toClass(ClassLoader,ProtectionDomain)}
*/
public final Class toClass(ClassLoader loader)
throws CannotCompileException
{
return getClassPool().toClass(this, loader);
}
/**
* Removes this CtClass object from the
* ClassPool.
* After this method is called, any method cannot be called on the
* removed CtClass object.
*
*
If get() in ClassPool is called
* with the name of the removed method,
* the ClassPool will read the class file again
* and constructs another CtClass object representing
* the same class.
*/
public void detach() {
ClassPool cp = getClassPool();
CtClass obj = cp.removeCached(getName());
if (obj != this)
cp.cacheCtClass(getName(), obj, false);
}
/**
* Disallows (or allows) automatically pruning this CtClass
* object.
*
*
* Javassist can automatically prune a CtClass object
* when toBytecode() (or toClass(),
* writeFile()) is called.
* Since a ClassPool holds all instances of CtClass
* even after toBytecode() (or toClass(),
* writeFile()) is called, pruning may significantly
* save memory consumption.
*
*
If ClassPool.doPruning is true, the automatic pruning
* is on by default. Otherwise, it is off. The default value of
* ClassPool.doPruning is false.
*
* @param stop disallow pruning if true. Otherwise, allow.
* @return the previous status of pruning. true if pruning is already stopped.
*
* @see #detach()
* @see #prune()
* @see ClassPool#doPruning
*/
public boolean stopPruning(boolean stop) { return true; }
/**
* Discards unnecessary attributes, in particular,
* CodeAttributes (method bodies) of the class,
* to minimize the memory footprint.
* After calling this method, the class is read only.
* It cannot be modified any more.
* Furthermore, toBytecode(),
* writeFile(), toClass(),
* or instrument() cannot be called.
* However, the method names and signatures in the class etc.
* are still accessible.
*
*
toBytecode(), writeFile(), and
* toClass() internally call this method if
* automatic pruning is on.
*
*
According to some experiments, pruning does not really reduce
* memory consumption. Only about 20%. Since pruning takes time,
* it might not pay off. So the automatic pruning is off by default.
*
* @see #stopPruning(boolean)
* @see #detach()
* @see ClassPool#doPruning
*
* @see #toBytecode()
* @see #toClass()
* @see #writeFile()
* @see #instrument(CodeConverter)
* @see #instrument(ExprEditor)
*/
public void prune() {}
/* Called by get() in ClassPool.
* CtClassType overrides this method.
*/
void incGetCounter() {}
/**
* If this method is called, the class file will be
* rebuilt when it is finally generated by
* toBytecode() and writeFile().
* For a performance reason, the symbol table of the
* class file may contain unused entries, for example,
* after a method or a filed is deleted.
* This method
* removes those unused entries. This removal will
* minimize the size of the class file.
*
* @since 3.8.1
*/
public void rebuildClassFile() {}
/**
* Converts this class to a class file.
* Once this method is called, further modifications are not
* possible any more.
*
* @return the contents of the class file.
*/
public byte[] toBytecode() throws IOException, CannotCompileException {
ByteArrayOutputStream barray = new ByteArrayOutputStream();
DataOutputStream out = new DataOutputStream(barray);
try {
toBytecode(out);
}
finally {
out.close();
}
return barray.toByteArray();
}
/**
* Writes a class file represented by this CtClass
* object in the current directory.
* Once this method is called, further modifications are not
* possible any more.
*
* @see #debugWriteFile()
*/
public void writeFile()
throws NotFoundException, IOException, CannotCompileException
{
writeFile(".");
}
/**
* Writes a class file represented by this CtClass
* object on a local disk.
* Once this method is called, further modifications are not
* possible any more.
*
* @param directoryName it must end without a directory separator.
* @see #debugWriteFile(String)
*/
public void writeFile(String directoryName)
throws CannotCompileException, IOException
{
DataOutputStream out = makeFileOutput(directoryName);
try {
toBytecode(out);
}
finally {
out.close();
}
}
protected DataOutputStream makeFileOutput(String directoryName) {
String classname = getName();
String filename = directoryName + File.separatorChar
+ classname.replace('.', File.separatorChar) + ".class";
int pos = filename.lastIndexOf(File.separatorChar);
if (pos > 0) {
String dir = filename.substring(0, pos);
if (!dir.equals("."))
new File(dir).mkdirs();
}
return new DataOutputStream(new BufferedOutputStream(
new DelayedFileOutputStream(filename)));
}
/**
* Writes a class file as writeFile() does although this
* method does not prune or freeze the class after writing the class
* file. Note that, once writeFile() or toBytecode()
* is called, it cannot be called again since the class is pruned and frozen.
* This method would be useful for debugging.
*/
public void debugWriteFile() {
debugWriteFile(".");
}
/**
* Writes a class file as writeFile() does although this
* method does not prune or freeze the class after writing the class
* file. Note that, once writeFile() or toBytecode()
* is called, it cannot be called again since the class is pruned and frozen.
* This method would be useful for debugging.
*
* @param directoryName it must end without a directory separator.
*/
public void debugWriteFile(String directoryName) {
try {
boolean p = stopPruning(true);
writeFile(directoryName);
defrost();
stopPruning(p);
}
catch (Exception e) {
throw new RuntimeException(e);
}
}
static class DelayedFileOutputStream extends OutputStream {
private FileOutputStream file;
private String filename;
DelayedFileOutputStream(String name) {
file = null;
filename = name;
}
private void init() throws IOException {
if (file == null)
file = new FileOutputStream(filename);
}
public void write(int b) throws IOException {
init();
file.write(b);
}
public void write(byte[] b) throws IOException {
init();
file.write(b);
}
public void write(byte[] b, int off, int len) throws IOException {
init();
file.write(b, off, len);
}
public void flush() throws IOException {
init();
file.flush();
}
public void close() throws IOException {
init();
file.close();
}
}
/**
* Converts this class to a class file.
* Once this method is called, further modifications are not
* possible any more.
*
*
This method dose not close the output stream in the end.
*
* @param out the output stream that a class file is written to.
*/
public void toBytecode(DataOutputStream out)
throws CannotCompileException, IOException
{
throw new CannotCompileException("not a class");
}
/**
* Makes a unique member name. This method guarantees that
* the returned name is not used as a prefix of any methods
* or fields visible in this class.
* If the returned name is XYZ, then any method or field names
* in this class do not start with XYZ.
*
* @param prefix the prefix of the member name.
*/
public String makeUniqueName(String prefix) {
throw new RuntimeException("not available in " + getName());
}
/* Invoked from ClassPool#compress().
* This method is overridden by CtClassType.
*/
void compress() {}
}