modified the ClassPool framework.

git-svn-id: http://anonsvn.jboss.org/repos/javassist/trunk@84 30ef5769-5b8d-40dd-aea6-55b5d6557bb3

Readme.html

@@ -255,10 +255,15 @@ see javassist.Dump.
 
 <h2>Changes</h2>
 
-<p>- version 2.7
+<p>- version 3.0
 
 <ul>
   <li>javassist.bytecode.annotation has been added.
+  <li>The ClassPool framework has been redesigned.
+     <ul>
+     <li>writeFile(), write(), ... in ClassPool have been moved to CtClass.
+     <li>The design of javassist.Translator has been changed.
+     </ul>
 
   <li>Now local variables were made available in the source text passed to
   CtBehavior.insertBefore(), MethodCall.replace(), etc.

sample/Test.java

@@ -37,7 +37,7 @@ public class Test {
 	    CtMethod fMethod = cc.getDeclaredMethod("f");
 	    CtMethod gMethod = CtNewMethod.copy(fMethod, "g", cc, null);
 	    cc.addMethod(gMethod);
-	    pool.writeFile("sample.Test");	// update the class file
+	    cc.writeFile();	// update the class file
 	    System.out.println("g() was added.");
 	}
     }

sample/evolve/DemoLoader.java

@@ -31,9 +31,8 @@ public class DemoLoader {
     public static void main(String[] args) throws Throwable {
         Evolution translator = new Evolution();
         ClassPool cp = ClassPool.getDefault();
-        cp.addTranslator(translator);
         Loader cl = new Loader();
-        cl.setClassPool(cp);
+        cl.addTranslator(cp, translator);
 
         translator.makeUpdatable("sample.evolve.WebPage");
         cl.run("sample.evolve.DemoServer", args);

sample/evolve/Evolution.java

@@ -43,16 +43,15 @@ public class Evolution implements Translator {
 	trapMethod = _pool.getMethod("sample.evolve.Sample", "make");
     }
 
-    public void onWrite(ClassPool _pool, String classname)
+    public void onWrite(ClassPool _pool, CtClass clazz)
 	throws NotFoundException, CannotCompileException
     {
-	onWriteUpdatable(classname);
+	onWriteUpdatable(clazz.getName());
 
 	/*
 	 * Replaces all the occurrences of the new operator with a call
 	 * to _makeInstance().
 	 */
-	CtClass clazz = _pool.get(classname);
 	CtClass absClass = updatableClass;
 	CodeConverter converter = new CodeConverter();
 	converter.replaceNew(absClass, absClass, handlerMethod);

sample/vector/VectorAssistant.java

@@ -96,7 +96,7 @@ public class VectorAssistant implements Assistant {
 
 	vec.addMethod(CtNewMethod.copy(addmethod, "add", vec, map));
 	vec.addMethod(CtNewMethod.copy(atmethod, "at", vec, map));
-	pool.writeFile(vec.getName());
+	vec.writeFile();
 	return vec;
     }
 
@@ -125,7 +125,7 @@ public class VectorAssistant implements Assistant {
 	m = CtNewMethod.wrapped(type, "at", args2,
 				null, atmethod, null, vec);
 	vec.addMethod(m);
-	pool.writeFile(vec.getName());
+	vec.writeFile();
 	return vec;
     }
 

src/main/javassist/ClassPool.java

@@ -83,10 +83,23 @@ import java.util.Hashtable;
  * @see javassist.ClassPath
  * @see javassist.Translator
  */
-public class ClassPool extends AbsClassPool {
-    protected AbsClassPool source;
+public class ClassPool {
+
+    /**
+     * Determines the search order.
+     *
+     * <p>If this field is true, <code>get()</code> first searches the
+     * class path associated to this <code>ClassPool</code> and then
+     * the class path associated with the parent <code>ClassPool</code>.
+     * Otherwise, the class path associated with the parent is searched
+     * first.
+     *
+     * <p>The default value is false.
+     */
+    public boolean childFirstLookup = false;
+
+    protected ClassPoolTail source;
     protected ClassPool parent;
-    protected Translator translator;
     protected Hashtable classes;        // should be synchronous
 
     /**
@@ -97,61 +110,23 @@ public class ClassPool extends AbsClassPool {
     /**
      * Creates a class pool.
      *
-     * @param src       the source of class files.  If it is null,
-     *                  the class search path is initially null.
-     * @param p         the parent of this class pool.
+     * @param p         the parent of this class pool.  If this is a root
+     *                  class pool, this parameter must be <code>null</code>.
      * @see javassist.ClassPool#getDefault()
      */
-    public ClassPool(ClassPool p) {
-        this(new ClassPoolTail(), p);
-    }
-
-    ClassPool(AbsClassPool src, ClassPool parent) {
+    public ClassPool(ClassPool parent) {
         this.classes = new Hashtable();
-        this.source = src;
+        this.source = new ClassPoolTail();
         this.parent = parent;
         if (parent == null) {
-            // if this has no parent, it must include primitive types
-            // even if this.source is not a ClassPoolTail.
             CtClass[] pt = CtClass.primitiveTypes;
             for (int i = 0; i < pt.length; ++i)
                 classes.put(pt[i].getName(), pt[i]);
         }
 
-        this.translator = null;
         this.cflow = null;
     }
 
-    /**
-     * Adds a new translator at the end of the translator chain.
-     *
-     * @param trans         a new translator associated with this class pool.
-     * @throws RuntimeException     if trans.start() throws an exception.
-     */
-    public void addTranslator(Translator trans) throws RuntimeException {
-        ClassPool cp;
-        if (translator == null)
-            cp = this;
-        else {
-            ClassPool s = this;
-            while (s.source instanceof ClassPool)  
-                s = (ClassPool)s.source;
-
-            cp = new ClassPool(s.source, parent);
-            s.source = cp;
-        }
-
-        cp.translator = trans;
-        try {
-            trans.start(cp);
-        }
-        catch (Exception e) {
-            throw new RuntimeException(
-                "Translator.start() throws an exception: "
-                + e.toString());
-        }
-    }
-
     /**
      * Returns the default class pool.
      * The returned object is always identical since this method is
@@ -210,12 +185,12 @@ public class ClassPool extends AbsClassPool {
          classes.remove(classname);
      }
 
-    /**
-     * Returns the class search path.
-     */
-    public String toString() {
-        return source.toString();
-    }
+     /**
+      * Returns the class search path.
+      */
+     public String toString() {
+         return source.toString();
+     }
 
     /**
      * Records a name that never exists.
@@ -231,14 +206,6 @@ public class ClassPool extends AbsClassPool {
         source.recordInvalidClassName(name);
     }
 
-    /**
-     * Returns the <code>Translator</code> object associated with
-     * this <code>ClassPool</code>.
-     *
-     * @deprecated
-     */
-    Translator getTranslator() { return translator; }
-
     /**
      * Records the <code>$cflow</code> variable for the field specified
      * by <code>cname</code> and <code>fname</code>.
@@ -267,133 +234,12 @@ public class ClassPool extends AbsClassPool {
     }
 
     /**
-     * Writes a class file specified with <code>classname</code>
-     * in the current directory.
-     * It never calls <code>onWrite()</code> on a translator.
-     * It is provided for debugging.
-     *
-     * @param classname         the name of the class written on a local disk.
-     */
-    public void debugWriteFile(String classname)
-        throws NotFoundException, CannotCompileException, IOException
-    {
-        debugWriteFile(classname, ".");
-    }
-
-    /**
-     * Writes a class file specified with <code>classname</code>.
-     * It never calls <code>onWrite()</code> on a translator.
-     * It is provided for debugging.
-     *
-     * @param classname         the name of the class written on a local disk.
-     * @param directoryName     it must end without a directory separator.
-     */
-    public void debugWriteFile(String classname, String directoryName)
-        throws NotFoundException, CannotCompileException, IOException
-    {
-        writeFile(classname, directoryName, false);
-    }
-
-    /* void writeFile(CtClass) should not be defined since writeFile()
-     * may be called on the class pool that does not contain the given
-     * CtClass object.
-     */
-
-    /**
-     * Writes a class file specified with <code>classname</code>
-     * in the current directory.
-     * It calls <code>onWrite()</code> on a translator.
-     *
-     * @param classname         the name of the class written on a local disk.
-     */
-    public void writeFile(String classname)
-        throws NotFoundException, CannotCompileException, IOException
-    {
-        writeFile(classname, ".");
-    }
-
-    /**
-     * Writes a class file specified with <code>classname</code>
-     * on a local disk.
-     * It calls <code>onWrite()</code> on a translator.
-     *
-     * @param classname         the name of the class written on a local disk.
-     * @param directoryName     it must end without a directory separator.
-     */
-    public void writeFile(String classname, String directoryName)
-        throws NotFoundException, CannotCompileException, IOException
-    {
-        writeFile(classname, directoryName, true);
-    }
-
-    private void writeFile(String classname, String directoryName,
-                           boolean callback)
-        throws NotFoundException, CannotCompileException, IOException
-    {
-        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();
-        }
-
-        DataOutputStream out
-            = new DataOutputStream(new BufferedOutputStream(
-                                new DelayedFileOutputStream(filename)));
-        write(classname, out, callback);
-        out.close();
-    }
-
-    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();
-        }
-    }
-
-    /**
-     * A simple class loader used by <code>writeAsClass()</code>
-     * in <code>ClassPool</code>.
+     * A simple class loader used by <code>toClass()</code>
+     * in <code>CtClass</code>.
      * This class loader is provided for convenience.  If you need more
      * complex functionality, you should write your own class loader.
      *
-     * @see ClassPool#writeAsClass(String)
+     * @see CtClass#forName(String)
      * @see CtClass#toClass()
      */
     public static class SimpleLoader extends ClassLoader {
@@ -413,186 +259,35 @@ public class ClassPool extends AbsClassPool {
         }
     };
 
-    private static SimpleLoader classLoader = new SimpleLoader();
+    private static SimpleLoader classLoader = null;
 
     /**
      * Returns a <code>java.lang.Class</code> object that has been loaded
-     * by <code>writeAsClass()</code>.  Such an object cannot be
+     * by <code>loadClass()</code>.  Such an object cannot be
      * obtained by <code>java.lang.Class.forName()</code> because it has
      * been loaded by an internal class loader of Javassist.
-     *
-     * @see #writeAsClass(String)
-     * @see javassist.CtClass#toClass()
      */
-    public static Class forName(String name) throws ClassNotFoundException {
+    static Class forName(String name) throws ClassNotFoundException {
+        if (classLoader == null)
+            classLoader = new SimpleLoader();
+
         return classLoader.loadClass(name);
     }
 
-    /**
-     * Returns a <code>java.lang.Class</code> object.
-     * It calls <code>write()</code> to obtain a class file and then
-     * loads the obtained class file into the JVM.  The returned
-     * <code>Class</code> object represents the loaded class.
-     *
-     * <p>This method is provided for convenience.  If you need more
-     * complex functionality, you should write your own class loader.
-     *
-     * <p>To load a class file, this method uses an internal class loader,
-     * which is an instance of <code>ClassPool.SimpleLoader</code>.
-     * Thus, that class file is not loaded by the system class loader,
-     * which should have loaded this <code>ClassPool</code> class.
-     * The internal class loader
-     * loads only the classes explicitly specified by this method
-     * <code>writeAsClass()</code>.  The other classes are loaded
-     * by the parent class loader (the sytem class loader) by delegation.
-     *
-     * <p>For example,
-     *
-     * <ul><pre>class Line { Point p1, p2; }</pre></ul>
-     *
-     * <p>If the class <code>Line</code> is loaded by the internal class
-     * loader and the class <code>Point</code> has not been loaded yet,
-     * then the class <code>Point</code> that the class <code>Line</code>
-     * refers to is loaded by the parent class loader.  There is no
-     * chance of modifying the definition of <code>Point</code> with
-     * Javassist.
-     *
-     * <p>The internal class loader is shared among all the instances
-     * of <code>ClassPool</code>.
-     *
-     * @param classname         a fully-qualified class name.
-     *
-     * @see #forName(String)
-     * @see javassist.CtClass#toClass()
-     * @see javassist.Loader
-     */
-    public Class writeAsClass(String classname)
+    static Class loadClass(String classname, byte[] classfile)
         throws NotFoundException, IOException, CannotCompileException
     {
+        if (classLoader == null)
+            classLoader = new SimpleLoader();
+
         try {
-            return classLoader.loadClass(classname, write(classname));
+            return classLoader.loadClass(classname, classfile);
         }
         catch (ClassFormatError e) {
             throw new CannotCompileException(e, classname);
         }
     }
 
-    /**
-     * Returns a byte array representing the class file.
-     * It calls <code>onWrite()</code> on a translator.
-     *
-     * @param classname         a fully-qualified class name.
-     */
-    public byte[] write(String classname)
-        throws NotFoundException, IOException, CannotCompileException
-    {
-        ByteArrayOutputStream barray = new ByteArrayOutputStream();
-        DataOutputStream out = new DataOutputStream(barray);
-        try {
-            write(classname, out, true);
-        }
-        finally {
-            out.close();
-        }
-
-        return barray.toByteArray();
-    }
-
-    /**
-     * Writes a class file specified by <code>classname</code>
-     * to a given output stream.
-     * It calls <code>onWrite()</code> on a translator.
-     *
-     * <p>This method does not close the output stream in the end.
-     *
-     * @param classname         a fully-qualified class name.
-     * @param out               an output stream
-     */
-    public void write(String classname, DataOutputStream out)
-        throws NotFoundException, CannotCompileException, IOException
-    {
-        write(classname, out, true);
-    }
-
-    private void write(String classname, DataOutputStream out,
-                       boolean callback)
-        throws NotFoundException, CannotCompileException, IOException
-    {
-        if (!write0(classname, out, callback))
-            throw new NotFoundException(classname);
-    }
-
-    boolean write0(String classname, DataOutputStream out, boolean callback)
-        throws NotFoundException, CannotCompileException, IOException
-    {
-        CtClass clazz = (CtClass)getCached(classname);
-        if (callback && translator != null
-                                && (clazz == null || !clazz.isFrozen())) {
-            translator.onWrite(this, classname);
-            // The CtClass object might be overwritten.
-            clazz = (CtClass)getCached(classname);
-        }
-
-        if (clazz == null || !clazz.isModified()) {
-            if (clazz != null)
-                clazz.freeze();
-
-            return source.write0(classname, out, callback);
-        }
-        else {
-            clazz.toBytecode(out);
-            return true;
-        }
-    }
-
-    /* for CtClassType.getClassFile2().  Don't delegate to the parent.
-     */
-    byte[] readSource(String classname)
-        throws NotFoundException, IOException, CannotCompileException
-    {
-        return source.readSource(classname);
-    }
-
-    /*
-     * Is invoked by CtClassType.setName().  Don't delegate to the parent.
-     */
-    synchronized void classNameChanged(String oldname, CtClass clazz) {
-        CtClass c = (CtClass)getCached(oldname);
-        if (c == clazz)             // must check this equation.
-            removeCached(oldname);  // see getAndRename().
-
-        String newName = clazz.getName();
-        checkNotFrozen(newName);
-        classes.put(newName, clazz);
-    }
-
-    /*
-     * Is invoked by CtClassType.setName() and methods in this class.
-     * This method throws an exception if the class is already frozen or
-     * if this class pool cannot edit the class since it is in a parent
-     * class pool.
-     */
-    void checkNotFrozen(String classname) throws RuntimeException {
-        CtClass c;
-        if (parent != null) {
-            try {
-                c = parent.get0(classname);
-            }
-            catch (NotFoundException e) {       // some error happens.
-                throw new RuntimeException(e.toString());
-            }
-
-            if (c != null)
-                throw new RuntimeException(classname
-                        + " is in a parent ClassPool.  Use the parent.");
-        }
-
-        c = getCached(classname);
-        if (c != null && c.isFrozen())
-            throw new RuntimeException(classname +
-                                       ": frozen class (cannot edit)");
-    }
-
     /**
      * Reads a class file and constructs a <code>CtClass</code>
      * object with a new name.
@@ -614,21 +309,30 @@ public class ClassPool extends AbsClassPool {
     public CtClass getAndRename(String orgName, String newName)
         throws NotFoundException
     {
-        CtClass clazz = null;
-        if (parent != null)
-            clazz = parent.get1(orgName);
-
-        if (clazz == null)
-            clazz = get1(orgName);
-
-        if (clazz == null)
-            throw new NotFoundException(orgName);
+        CtClass clazz = get0(orgName, false);
+        if (clazz instanceof CtClassType)
+            ((CtClassType)clazz).setClassPool(this);
 
         clazz.setName(newName);         // indirectly calls
                                         // classNameChanged() in this class
         return clazz;
     }
 
+    /*
+     * This method is invoked by CtClassType.setName().  It removes a
+     * CtClass object from the hash table and inserts it with the new
+     * name.  Don't delegate to the parent.
+     */
+    synchronized void classNameChanged(String oldname, CtClass clazz) {
+        CtClass c = (CtClass)getCached(oldname);
+        if (c == clazz)             // must check this equation.
+            removeCached(oldname);  // see getAndRename().
+
+        String newName = clazz.getName();
+        checkNotFrozen(newName);
+        classes.put(newName, clazz);
+    }
+
     /**
      * Reads a class file from the source and returns a reference
      * to the <code>CtClass</code>
@@ -646,7 +350,7 @@ public class ClassPool extends AbsClassPool {
      * @param classname         a fully-qualified class name.
      */
     public CtClass get(String classname) throws NotFoundException {
-        CtClass clazz = get0(classname);
+        CtClass clazz = get0(classname, true);
         if (clazz == null)
             throw new NotFoundException(classname);
         else
@@ -654,33 +358,51 @@ public class ClassPool extends AbsClassPool {
     }
 
     /**
+     * @param useCache  false if the cached CtClass must be ignored.
+     * @param searchParent  false if the parent class pool is not searched.
      * @return null     if the class could not be found.
      */
-    private synchronized CtClass get0(String classname)
+    protected synchronized CtClass get0(String classname, boolean useCache)
         throws NotFoundException
     {
-        CtClass clazz;
-        clazz = getCached(classname);
-        if (clazz != null) return clazz;
-        if (parent != null) {
-            clazz = parent.get0(classname);
+        CtClass clazz = null;
+        if (useCache) {
+            clazz = getCached(classname);
             if (clazz != null)
                 return clazz;
         }
 
-        if (clazz == null) {
-            clazz = get1(classname);
+        if (!childFirstLookup && parent != null) {
+            clazz = parent.get0(classname, useCache);
             if (clazz != null)
+                return clazz;
+        }
+
+        clazz = createCtClass(classname, useCache);
+        if (clazz != null) {
+            if (useCache)
                 classes.put(classname, clazz);
+
+            return clazz;
         }
 
+        if (childFirstLookup && parent != null)
+            clazz = parent.get0(classname, useCache);
+
         return clazz;
     }
 
-    protected CtClass get1(String classname) throws NotFoundException {
+    /**
+     * Creates a CtClass object representing the specified class.
+     * It first examines whether or not the corresponding class
+     * file exists.  If yes, it creates a CtClass object.
+     *
+     * @return null if the class file could not be found.
+     */
+    private CtClass createCtClass(String classname, boolean useCache) {
         if (classname.endsWith("[]")) {
             String base = classname.substring(0, classname.indexOf('['));
-            if (getCached(base) == null && find(base) == null)
+            if ((!useCache || getCached(base) == null) && find(base) == null)
                 return null;
             else
                 return new CtArray(classname, this);
@@ -693,16 +415,57 @@ public class ClassPool extends AbsClassPool {
     }
 
     /**
-     * Obtains the URL of the class file specified by classname.
-     * This method does not delegate to the parent pool.
+     * Searches the class path to obtain the URL of the class file
+     * specified by classname.  It is also used to determine whether
+     * the class file exists.
      *
      * @param classname     a fully-qualified class name.
      * @return null if the class file could not be found.
+     * @see CtClassType#getURL()
      */
     URL find(String classname) {
         return source.find(classname);
     }
 
+    /*
+     * Is invoked by CtClassType.setName() and methods in this class.
+     * This method throws an exception if the class is already frozen or
+     * if this class pool cannot edit the class since it is in a parent
+     * class pool.
+     */
+    void checkNotFrozen(String classname) throws RuntimeException {
+        CtClass clazz = getCached(classname);
+        if (clazz == null) {
+            if (!childFirstLookup && parent != null) {
+                try {
+                    clazz = parent.get0(classname, true);
+                }
+                catch (NotFoundException e) {}
+                if (clazz != null)
+                    throw new RuntimeException(classname
+                            + " is in a parent ClassPool.  Use the parent.");
+            }
+        }
+        else
+            if (clazz.isFrozen())
+                throw new RuntimeException(classname +
+                                       ": frozen class (cannot edit)");
+    }
+
+    /* for CtClassType.getClassFile2().  Don't delegate to the parent.
+     */
+    byte[] readSource(String classname)
+        throws NotFoundException, IOException, CannotCompileException
+    {
+        return source.readSource(classname);
+    }
+
+    void writeClassfile(String classname, OutputStream out)
+        throws NotFoundException, IOException, CannotCompileException
+    {
+        source.writeClassfile(classname, out);
+    }
+
     /**
      * Reads class files from the source and returns an array of
      * <code>CtClass</code>

src/main/javassist/ClassPoolTail.java

@@ -128,7 +128,7 @@ final class JarClassPath implements ClassPath {
     }
 }
 
-final class ClassPoolTail extends AbsClassPool {
+final class ClassPoolTail {
     protected ClassPathList pathList;
     private Hashtable packages;         // should be synchronized.
 
@@ -151,62 +151,6 @@ final class ClassPoolTail extends AbsClassPool {
         return buf.toString();
     }
 
-    /**
-     * You can record "System" so that java.lang.System can be quickly
-     * found although "System" is not a package name.
-     */
-    public void recordInvalidClassName(String name) {
-        packages.put(name, name);
-    }
-
-    /**
-     * @return the contents of the class file. 
-     * @throws NotFoundException    if the file could not be found.
-     */
-    byte[] readSource(String classname)
-        throws NotFoundException, IOException, CannotCompileException
-    {
-        byte[] b = readClassfile(classname);
-        if (b == null)
-            throw new NotFoundException(classname);
-        else
-            return b;
-    }
-
-    /**
-     * @return null                 if the file could not be found.
-     * @throws NotFoundException    if any error is reported by ClassPath.
-     */
-    boolean write0(String classname, DataOutputStream out, boolean callback)
-        throws NotFoundException, CannotCompileException, IOException
-    {
-        byte[] b = readClassfile(classname);
-        if (b == null)
-            return false;       // not found
-        else {
-            out.write(b, 0, b.length);
-            return true;
-        }
-    }
-
-    /*
-    -- faster version --
-    void checkClassName(String classname) throws NotFoundException {
-        if (find(classname) == null)
-            throw new NotFoundException(classname);
-    }
-
-    -- slower version --
-
-    void checkClassName(String classname) throws NotFoundException {
-        InputStream fin = openClassfile(classname);
-        try {
-            fin.close();
-        }
-        catch (IOException e) {}
-    }
-    */
-
     public synchronized ClassPath insertClassPath(ClassPath cp) {
         pathList = new ClassPathList(cp, pathList);
         return cp;
@@ -272,6 +216,65 @@ final class ClassPoolTail extends AbsClassPool {
         return new DirClassPath(pathname);
     }
 
+    /**
+     * You can record "System" so that java.lang.System can be quickly
+     * found although "System" is not a package name.
+     */
+    public void recordInvalidClassName(String name) {
+        packages.put(name, name);
+    }
+
+    /**
+     * @return the contents of the class file. 
+     * @throws NotFoundException    if the file could not be found.
+     */
+    byte[] readSource(String classname)
+        throws NotFoundException, IOException, CannotCompileException
+    {
+        byte[] b = readClassfile(classname);
+        if (b == null)
+            throw new NotFoundException(classname);
+        else
+            return b;
+    }
+
+    /**
+     * This method does not close the output stream.
+     */
+    void writeClassfile(String classname, OutputStream out)
+        throws NotFoundException, IOException, CannotCompileException
+    {
+        InputStream fin = openClassfile(classname);
+        if (fin == null)
+            throw new NotFoundException(classname);
+
+        try {
+            copyStream(fin, out);
+        }
+        finally {
+            fin.close();
+        }
+    }
+
+    /*
+    -- faster version --
+    void checkClassName(String classname) throws NotFoundException {
+        if (find(classname) == null)
+            throw new NotFoundException(classname);
+    }
+
+    -- slower version --
+
+    void checkClassName(String classname) throws NotFoundException {
+        InputStream fin = openClassfile(classname);
+        try {
+            fin.close();
+        }
+        catch (IOException e) {}
+    }
+    */
+
+
     /**
      * Obtains the contents of the class file for the class
      * specified by <code>classname</code>.
@@ -337,7 +340,9 @@ final class ClassPoolTail extends AbsClassPool {
     }
 
     /**
-     * Obtains the URL of the class file specified by classname.
+     * Searches the class path to obtain the URL of the class file
+     * specified by classname.  It is also used to determine whether
+     * the class file exists.
      *
      * @param classname     a fully-qualified class name.
      * @return null if the class file could not be found.
@@ -360,7 +365,7 @@ final class ClassPoolTail extends AbsClassPool {
     }
 
     /**
-     * Reads an input stream until it reaches the end.
+     * Reads from an input stream until it reaches the end.
      *
      * @return          the contents of that input stream
      */
@@ -393,4 +398,33 @@ final class ClassPoolTail extends AbsClassPool {
 
         throw new IOException("too much data");
     }
+
+    /**
+     * Reads from an input stream and write to an output stream
+     * until it reaches the end.  This method does not close the
+     * streams.
+     */
+    public static void copyStream(InputStream fin, OutputStream fout)
+        throws IOException
+    {
+        int bufsize = 4096;
+        for (int i = 0; i < 8; ++i) {
+            byte[] buf = new byte[bufsize];
+            int size = 0;
+            int len = 0;
+            do {
+                len = fin.read(buf, size, bufsize - size);
+                if (len >= 0)
+                    size += len;
+                else {
+                    fout.write(buf, 0, size);
+                    return;
+                }
+            } while (size < bufsize);
+            fout.write(buf);
+            bufsize *= 2;
+        }
+
+        throw new IOException("too much data");
+    }
 }

src/main/javassist/CtClass.java

@@ -15,8 +15,7 @@
 
 package javassist;
 
-import java.io.DataOutputStream;
-import java.io.IOException;
+import java.io.*;
 import javassist.bytecode.*;
 import java.util.Collection;
 import javassist.expr.ExprEditor;
@@ -36,7 +35,7 @@ public abstract class CtClass {
     /**
      * The version number of this release.
      */
-    public static final String version = "2.7 alpha 8";
+    public static final String version = "3.0 alpha 1";
 
     /**
      * Prints the version number and the copyright notice.
@@ -815,22 +814,55 @@ public abstract class CtClass {
      * Once this method is called, further modifications are not
      * possible any more.
      *
-     * <p>This method is equivalent to:
-     * <ul><pre>this.getClassPool().writeAsClass(this.getName())</pre></ul>
-     *
-     * <p>See the description of <code>ClassPool.writeAsClass()</code>
-     * before you use this method.
-     * This method is provided for convenience.  If you need more
+     * <p>This method is provided for convenience.  If you need more
      * complex functionality, you should write your own class loader.
      *
-     * @see javassist.ClassPool#writeAsClass(String)
-     * @see javassist.ClassPool#forName(String)
-     * @see javassist.Loader
+     * <p>To load a class file, this method uses an internal class loader,
+     * which is an instance of <code>ClassPool.SimpleLoader</code>.
+     * Thus, that class file is not loaded by the system class loader,
+     * which should have loaded this <code>CtClass</code> class.
+     * The internal class loader
+     * loads only the classes explicitly specified by this method
+     * <code>toClass()</code>.  The other classes are loaded
+     * by the parent class loader (usually the sytem class loader)
+     * by delegation.
+     *
+     * <p>For example,
+     *
+     * <ul><pre>class Line { Point p1, p2; }</pre></ul>
+     *
+     * <p>If the class <code>Line</code> is loaded by the internal class
+     * loader and the class <code>Point</code> has not been loaded yet,
+     * then the class <code>Point</code> that the class <code>Line</code>
+     * refers to is loaded by the parent class loader.  There is no
+     * chance of modifying the definition of <code>Point</code> with
+     * Javassist.
+     *
+     * <p>The internal class loader is shared among all the instances
+     * of <code>ClassPool</code>.
+     *
+     * @return the <code>Class</code> object representing the loaded class.  
+     * @see CtClass#forName(String)
+     * @see ClassPool.SimpleClassLoader
+     * @see Loader
      */
     public Class toClass()
         throws NotFoundException, IOException, CannotCompileException
     {
-        return getClassPool2().writeAsClass(getName());
+        return ClassPool.loadClass(getName(), toBytecode());
+    }
+
+    /**
+     * Returns a <code>java.lang.Class</code> object that has been loaded
+     * by <code>toClass()</code>.  Such an object cannot be
+     * obtained by <code>java.lang.Class.forName()</code> because it has
+     * been loaded by an internal class loader of Javassist.
+     *
+     * @see CtClass#toClass()
+     * @see ClassPool.SimpleClassLoader
+     */
+    public static Class forName(String name) throws ClassNotFoundException {
+        return ClassPool.forName(name);
     }
 
     /**
@@ -838,15 +870,21 @@ public abstract class CtClass {
      * Once this method is called, further modifications are not
      * possible any more.
      *
-     * <p>This method is equivalent to:
-     * <ul><pre>this.getClassPool().write(this.getName())</pre></ul>
-     *
-     * @see javassist.ClassPool#write(String)
+     * @return the contents of the class file.
      */
     public byte[] toBytecode()
         throws NotFoundException, IOException, CannotCompileException
     {
-        return getClassPool2().write(getName());
+        ByteArrayOutputStream barray = new ByteArrayOutputStream();
+        DataOutputStream out = new DataOutputStream(barray);
+        try {
+            toBytecode(out);
+        }
+        finally {
+            out.close();
+        }
+
+        return barray.toByteArray();
     }
 
     /**
@@ -854,25 +892,84 @@ public abstract class CtClass {
      * object in the current directory.
      * Once this method is called, further modifications are not
      * possible any more.
-     *
-     * <p>This method is equivalent to:
-     * <ul><pre>this.getClassPool().writeFile(this.getName())</pre></ul>
-     *
-     * @see javassist.ClassPool#writeFile(String)
      */
     public void writeFile()
         throws NotFoundException, IOException, CannotCompileException
     {
-        getClassPool2().writeFile(getName());
+        writeFile(".");
     }
 
-    private ClassPool getClassPool2() throws CannotCompileException {
-        ClassPool cp = getClassPool();
-        if (cp == null)
-            throw new CannotCompileException(
-                        getName() + ": no ClassPool found. not a class?");
-        else
-            return cp;
+    /**
+     * Writes a class file represented by this <code>CtClass</code>
+     * 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.
+     */
+    public void writeFile(String directoryName)
+        throws NotFoundException, CannotCompileException, IOException
+    {
+        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();
+        }
+
+        DataOutputStream out
+            = new DataOutputStream(new BufferedOutputStream(
+                                new DelayedFileOutputStream(filename)));
+        try {
+            toBytecode(out);
+        }
+        finally {
+            out.close();
+        }
+    }
+
+    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();
+        }
     }
 
     /**
@@ -880,16 +977,11 @@ public abstract class CtClass {
      * Once this method is called, further modifications are not
      * possible any more.
      *
-     * <p>If this method is used to obtain a byte array representing
-     * the class file, <code>Translator.onWrite()</code> is never
-     * called on this class.  <code>ClassPool.write()</code> should
-     * be used.
-     *
      * <p>This method dose not close the output stream in the end.
      *
      * @param out       the output stream that a class file is written to.
      */
-    void toBytecode(DataOutputStream out)
+    public void toBytecode(DataOutputStream out)
         throws CannotCompileException, IOException
     {
         throw new CannotCompileException("not a class");

src/main/javassist/CtClassType.java

@@ -34,10 +34,10 @@ import java.util.List;
  * Class types.
  */
 class CtClassType extends CtClass {
-    protected ClassPool classPool;
-    protected boolean wasChanged;
-    protected boolean wasFrozen;
-    protected ClassFile classfile;
+    ClassPool classPool;
+    boolean wasChanged;
+    boolean wasFrozen;
+    ClassFile classfile;
 
     private CtField fieldsCache;
     private CtConstructor constructorsCache;
@@ -127,6 +127,8 @@ class CtClassType extends CtClass {
 
     public ClassPool getClassPool() { return classPool; }
 
+    void setClassPool(ClassPool cp) { classPool = cp; }
+
     public URL getURL() throws NotFoundException {
         URL url = classPool.find(getName());
         if (url == null)
@@ -762,23 +764,25 @@ class CtClassType extends CtClass {
         }
     }
 
-    void toBytecode(DataOutputStream out)
+    public void toBytecode(DataOutputStream out)
         throws CannotCompileException, IOException
     {
-        ClassFile cf = getClassFile2();
         try {
-            modifyClassConstructor(cf);
-            modifyConstructors(cf);
+            if (isModified()) {
+                ClassFile cf = getClassFile2();
+                modifyClassConstructor(cf);
+                modifyConstructors(cf);
+                cf.write(out);
+                out.flush();
+            }
+            else
+                classPool.writeClassfile(getName(), out);
+
+            wasFrozen = true;
         }
         catch (NotFoundException e) {
             throw new CannotCompileException(e);
         }
-
-        wasFrozen = true;
-        try {
-            cf.write(out);
-            out.flush();
-        }
         catch (IOException e) {
             throw new CannotCompileException(e);
         }

src/main/javassist/CtNewClass.java

@@ -55,7 +55,7 @@ class CtNewClass extends CtClassType {
         super.addConstructor(c);
     }
 
-    void toBytecode(DataOutputStream out)
+    public void toBytecode(DataOutputStream out)
         throws CannotCompileException, IOException
     {
         if (!hasConstructor)

src/main/javassist/Loader.java

@@ -44,8 +44,9 @@ import java.util.Vector;
  * public class Main {
  *   public static void main(String[] args) throws Throwable {
  *     MyTranslator myTrans = new MyTranslator();
- *     ClassPool cp = ClassPool.getDefault(myTrans);
+ *     ClassPool cp = ClassPool.getDefault();
  *     Loader cl = new Loader(cp);
+ *     cl.addTranslator(cp, myTrans);
  *     cl.run("MyApp", args);
  *   }
  * }
@@ -130,6 +131,7 @@ public class Loader extends ClassLoader {
     private Hashtable notDefinedHere;   // must be atomic.
     private Vector notDefinedPackages;  // must be atomic.
     private ClassPool source;
+    private Translator translator;
 
     /**
      * Specifies the algorithm of class loading.
@@ -176,6 +178,7 @@ public class Loader extends ClassLoader {
         notDefinedHere = new Hashtable();
         notDefinedPackages = new Vector();
         source = cp;
+        translator = null;
         delegateLoadingOf("javassist.Loader");
     }
 
@@ -201,6 +204,21 @@ public class Loader extends ClassLoader {
         source = cp;
     }
 
+    /**
+     * Adds a translator, which is called whenever a class is loaded.
+     *
+     * @param cp        the <code>ClassPool</code> object for obtaining
+     *                  a class file.
+     * @param t         a translator.
+     */
+    public void addTranslator(ClassPool cp, Translator t)
+        throws NotFoundException, CannotCompileException
+    {
+        source = cp;
+        translator = t;
+        t.start(cp);
+    }
+
     /**
      * Loads a class with an instance of <code>Loader</code>
      * and calls <code>main()</code> of that class.
@@ -291,8 +309,13 @@ public class Loader extends ClassLoader {
     protected Class findClass(String name) {
         byte[] classfile;
         try {
-            if (source != null)
-                classfile = source.write(name);
+            if (source != null) {
+                CtClass c = source.get(name);
+                if (translator != null)
+                    translator.onWrite(source, c);
+
+                classfile = c.toBytecode();
+            }
             else {
                 String jarname = "/" + name.replace('.', '/') + ".class";
                 InputStream in = this.getClass().getResourceAsStream(jarname);
@@ -369,7 +392,7 @@ public class Loader extends ClassLoader {
     protected Package getPackage(String name) {
         return super.getPackage(name);
     }
-        /*
+    /*
         // Package p = super.getPackage(name);
         Package p = null;
         if (p == null)

src/main/javassist/Translator.java

@@ -16,45 +16,35 @@
 package javassist;
 
 /**
- * An observer of <code>ClassPool</code>.
+ * An observer of <code>Loader</code>.
  * The users can define a class implementing this
  * interface and attach an instance of that class to a
- * <code>ClassPool</code> object so that it can translate a class file
- * when the class file is loaded into the JVM, for example.
+ * <code>Loader</code> object so that it can translate a class file
+ * when the class file is loaded into the JVM.
  *
- * @see ClassPool#ClassPool(ClassPool,Translator)
- * @see ClassPool#getDefault(Translator)
+ * @see Loader
  */
 public interface Translator {
     /**
-     * Is invoked by a <code>ClassPool</code> for initialization
-     * when the object is attached to a <code>ClassPool</code> object.
+     * Is invoked by a <code>Loader</code> for initialization
+     * when the object is attached to the <code>Loader</code> object.
      *
      * @param pool      the <code>ClassPool</code> that this translator
-     *                          is attached to.
-     *
-     * @see ClassPool#ClassPool(ClassPool,Translator)
-     * @see ClassPool#getDefault(Translator)
+     *                          should use.
+     * @see Loader
      */
     void start(ClassPool pool)
         throws NotFoundException, CannotCompileException;
 
     /**
-     * Is invoked by a <code>ClassPool</code> for notifying that
-     * a class is written out to an output stream.
-     *
-     * <p>If <code>CtClass.frozen()</code> is true, that is, if the class has been
-     * already modified and written, then onWrite() is not invoked.
+     * Is invoked by a <code>Loader</code> for notifying that
+     * a class is loaded.
      *
      * @param pool      the <code>ClassPool</code> that this translator
-     *                          is attached to.
-     * @param classname         a fully-qualified class name
-     *
-     * @see ClassPool#writeFile(String)
-     * @see ClassPool#writeFile(String, String)
-     * @see ClassPool#write(String)
-     * @see ClassPool#write(String,DataOutputStream)
+     *                          should use.
+     * @param clazz     the class that is being loaded.
+     * @see Loader
      */
-    void onWrite(ClassPool pool, String classname)
+    void onWrite(ClassPool pool, CtClass clazz)
         throws NotFoundException, CannotCompileException;
 }

src/main/javassist/reflect/Compiler.java

@@ -91,7 +91,7 @@ public class Compiler {
     {
         Reflection implementor = new Reflection();
         ClassPool pool = ClassPool.getDefault();
-        pool.addTranslator(implementor);
+        implementor.start(pool);
 
         for (int i = 0; i < n; ++i) {
             CtClass c = pool.get(entries[i].classname);
@@ -121,8 +121,11 @@ public class Compiler {
                 System.err.println(c.getName() + ": not reflective");
         }
 
-        for (int i = 0; i < n; ++i)
-            pool.writeFile(entries[i].classname);
+        for (int i = 0; i < n; ++i) {
+            CtClass c = pool.get(entries[i].classname);
+            implementor.onWrite(pool, c);
+            c.writeFile();
+        }
     }
 
     private static int parse(String[] args, CompiledClass[] result) {

src/main/javassist/reflect/Loader.java

@@ -128,14 +128,13 @@ public class Loader extends javassist.Loader {
     /**
      * Constructs a new class loader.
      */
-    public Loader() {
+    public Loader() throws CannotCompileException, NotFoundException {
         super();
         delegateLoadingOf("javassist.reflect.Loader");
 
         reflection = new Reflection();
         ClassPool pool = ClassPool.getDefault();
-        pool.addTranslator(reflection); 
-        setClassPool(pool);
+        addTranslator(pool, reflection);
     }
 
     /**

src/main/javassist/reflect/Reflection.java

@@ -21,9 +21,6 @@ import javassist.CtMethod.ConstParameter;
 /**
  * The class implementing the reflection mechanism.
  *
- * <p>This class is used with <code>ClassPool</code>.
- * Note that it implements an interface <code>javassist.Translator</code>.
- *
  * <p>If a class is reflective,
  * then all the method invocations on every
  * instance of that class are intercepted by the runtime
@@ -58,8 +55,6 @@ import javassist.CtMethod.ConstParameter;
  * @see javassist.reflect.Metaobject
  * @see javassist.reflect.Loader
  * @see javassist.reflect.Compiler
- * @see javassist.ClassPool
- * @see javassist.Translator
  */
 public class Reflection implements Translator {
 
@@ -120,11 +115,10 @@ public class Reflection implements Translator {
      * Inserts hooks for intercepting accesses to the fields declared
      * in reflective classes.
      */
-    public void onWrite(ClassPool pool, String classname)
+    public void onWrite(ClassPool pool, CtClass clazz)
         throws CannotCompileException, NotFoundException
     {
-        CtClass c = pool.get(classname);
-        c.instrument(converter);
+        clazz.instrument(converter);
     }
 
     /**

src/main/javassist/rmi/AppletServer.java

@@ -82,8 +82,7 @@ public class AppletServer extends Webserver {
         exportedNames = new Hashtable();
         exportedObjects = new Vector();
         stubGen = gen;
-        loader.addTranslator(gen);
-        setClassPool(loader);
+        addTranslator(loader, gen);
     }
 
     /**

src/main/javassist/rmi/StubGenerator.java

@@ -82,7 +82,7 @@ public class StubGenerator implements Translator {
             = new CtClass[] { pool.get("javassist.rmi.RemoteException") };
     }
 
-    public void onWrite(ClassPool pool, String classname) {}
+    public void onWrite(ClassPool pool, CtClass clazz) {}
 
     /**
      * Returns <code>true</code> if the specified class is a proxy class

src/main/javassist/web/Webserver.java

@@ -18,7 +18,7 @@ package javassist.web;
 import java.net.*;
 import java.io.*;
 import java.util.Date;
-import javassist.ClassPool;
+import javassist.*;
 
 /**
  * A web server for Javassist.
@@ -28,9 +28,6 @@ import javassist.ClassPool;
  * does not allow an applet to create and use a class loader,
  * instrumenting class files must be done by this web server.
  *
- * <p>Programmers can register a <code>ClassPool</code> object for
- * instrumenting class files when they are sent to web browsers.
- *
  * <p><b>Note:</b> although this class is included in the Javassist API,
  * it is provided as a sample implementation of the web server using
  * Javassist.  Especially, there might be security flaws in this server.
@@ -39,6 +36,7 @@ import javassist.ClassPool;
 public class Webserver {
     private ServerSocket socket;
     private ClassPool classPool;
+    protected Translator translator;
 
     private final static byte[] endofline = { 0x0d, 0x0a };
     private byte[] filebuffer = new byte[4096];
@@ -105,6 +103,7 @@ public class Webserver {
     public Webserver(int port) throws IOException {
         socket = new ServerSocket(port);
         classPool = null;
+        translator = null;
     }
 
     /**
@@ -115,6 +114,22 @@ public class Webserver {
         classPool = loader;
     }
 
+    /**
+     * Adds a translator, which is called whenever a client requests
+     * a class file.
+     *
+     * @param cp        the <code>ClassPool</code> object for obtaining
+     *                  a class file.
+     * @param t         a translator.
+     */
+    public void addTranslator(ClassPool cp, Translator t)
+        throws NotFoundException, CannotCompileException
+    {
+        classPool = cp;
+        translator = t;
+        t.start(classPool);
+    }
+
     /**
      * Closes the socket.
      */
@@ -322,9 +337,13 @@ public class Webserver {
         String classname
             = filename.substring(0, length - 6).replace('/', '.');
         try {
-            classfile = classPool.write(classname);
+            CtClass c = classPool.get(classname);
+            if (translator != null)
+                translator.onWrite(classPool, c);
+
+            classfile = c.toBytecode();
             if (debugDir != null)
-                classPool.writeFile(classname, debugDir);
+                c.writeFile(debugDir);
         }
         catch (Exception e) {
             throw new BadHttpRequest(e);