ctclass.java

Javassist是一个开源的分析、编辑和创建Java字节码的类库。是由东京技术学院的数学和计算机科学系的 Shigeru Chiba 所创建的。它已加入了开放源代码JBoss 应用服务器项目,通过使

/*
 * Javassist, a Java-bytecode translator toolkit.
 * Copyright (C) 1999-2006 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.
 *
 * 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.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 <code>CtClass</code> represents a class.
 * It is obtained from <code>ClassPool</code>.
 *
 * @see ClassPool#get(String)
 */
public abstract class CtClass {
    protected String qualifiedName;

    /**
     * The version number of this release.
     */
    public static final String version = "3.4";

    /**
     * Prints the version number and the copyright notice.
     *
     * <p>The following command invokes this method:
     *
     * <ul><pre>java -jar javassist.jar</pre></ul>
     */
    public static void main(String[] args) {
        System.out.println("Javassist version " + CtClass.version);
        System.out.println("Copyright (C) 1999-2006 Shigeru Chiba."
                           + " All Rights Reserved.");
    }

    static final String javaLangObject = "java.lang.Object";

    /**
     * The <code>CtClass</code> object representing
     * the <code>boolean</code> type.
     */
    public static CtClass booleanType;

    /**
     * The <code>CtClass</code> object representing
     * the <code>char</code> type.
     */
    public static CtClass charType;

    /**
     * The <code>CtClass</code> object representing
     * the <code>byte</code> type.
     */
    public static CtClass byteType;

    /**
     * The <code>CtClass</code> object representing
     * the <code>short</code> type.
     */
    public static CtClass shortType;

    /**
     * The <code>CtClass</code> object representing
     * the <code>int</code> type.
     */
    public static CtClass intType;

    /**
     * The <code>CtClass</code> object representing
     * the <code>long</code> type.
     */
    public static CtClass longType;

    /**
     * The <code>CtClass</code> object representing
     * the <code>float</code> type.
     */
    public static CtClass floatType;

    /**
     * The <code>CtClass</code> object representing
     * the <code>double</code> type.
     */
    public static CtClass doubleType;

    /**
     * The <code>CtClass</code> object representing
     * the <code>void</code> 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 <code>ClassPool</code> for this class.
     */
    public ClassPool getClassPool() { return null; }

    /**
     * Returns a class file for this class.
     *
     * <p>This method is not available if <code>isFrozen()</code>
     * 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
     * <code>getClassFile()</code>.
     *
     * <p>The <code>ClassFile</code> object obtained by this method
     * is read only.  Changes to this object might not be reflected
     * on a class file generated by <code>toBytecode()</code>,
     * <code>toClass()</code>, etc.
     *
     * <p>This method is available even if <code>isFrozen()</code>
     * 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; }

    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.
     *
     * <p>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.
     *
     * <p>If <code>defrost()</code> 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 <code>true</code> if this object represents a primitive
     * Java type: boolean, byte, char, short, int, long, float, double,
     * or void.
     */
    public boolean isPrimitive() { return false; }

    /**
     * Returns <code>true</code> 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 <code>null</code>.
     */
    public CtClass getComponentType() throws NotFoundException {
        return null;
    }

    /**
     * Returns <code>true</code> if this class extends or implements
     * <code>clazz</code>.  It also returns <code>true</code> if
     * this class is the same as <code>clazz</code>.
     */
    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 <code>null</code>.
     */
    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;
    }

    /**
     * Substitutes <code>newName</code> for all occurrences of a class
     * name <code>oldName</code> 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 <code>map</code>.
     *
     * <p>All the class names appearing in the class file are tested
     * with <code>map</code> 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 <code>ClassMap</code> so that <code>get()</code>
     * 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.
     *
     * <p>This method may return <code>null</code>.
     */
    public 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.renameClass(cm);
            return cm.values();
        }
        else
            return null;
    }

    /**
     * Determines whether this object represents a class or an interface.
     * It returns <code>true</code> if this object represents an interface.
     */
    public boolean isInterface() {
        return false;
    }

    /**
     * Determines whether this object represents an annotation type.
     * It returns <code>true</code> if this object represents an annotation type.
     *
     * @since 3.2