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diff --git a/sample/vector/VectorAssistant.java b/sample/vector/VectorAssistant.java
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+package sample.vector;
+
+import java.io.IOException;
+import javassist.*;
+import sample.preproc.Assistant;
+
+/**
+ * This is a Javassist program which produce a new class representing
+ * vectors of a given type.  For example,
+ *
+ * <ul>import java.util.Vector by sample.vector.VectorAssistant(int)</ul>
+ *
+ * <p>requests the Javassist preprocessor to substitute the following
+ * lines for the original import declaration:
+ *
+ * <ul><pre>
+ * import java.util.Vector;
+ * import sample.vector.intVector;
+ * </pre></ul>
+ *
+ * <p>The Javassist preprocessor calls <code>VectorAssistant.assist()</code>
+ * and produces class <code>intVector</code> equivalent to:
+ *
+ * <ul><pre>
+ * package sample.vector;
+ *
+ * public class intVector extends Vector {
+ *   pubilc void add(int value) {
+ *     addElement(new Integer(value));
+ *   }
+ *
+ *   public int at(int index) {
+ *     return elementAt(index).intValue();
+ *   }
+ * }
+ * </pre></ul>
+ *
+ * <p><code>VectorAssistant.assist()</code> uses
+ * <code>sample.vector.Sample</code> and <code>sample.vector.Sample2</code>
+ * as a template to produce the methods <code>add()</code> and
+ * <code>at()</code>.
+ */
+public class VectorAssistant implements Assistant {
+    public final String packageName = "sample.vector.";
+
+    /**
+     * Calls <code>makeSubclass()</code> and produces a new vector class.
+     * This method is called by a <code>sample.preproc.Compiler</code>.
+     *
+     * @see sample.preproc.Compiler
+     */
+    public CtClass[] assist(ClassPool pool, String vec, String[] args)
+	throws CannotCompileException
+    {
+	if (args.length != 1)
+	    throw new CannotCompileException(
+			"VectorAssistant receives a single argument.");
+
+	try {
+	    CtClass subclass;
+	    CtClass elementType = pool.get(args[0]);
+	    if (elementType.isPrimitive())
+		subclass = makeSubclass2(pool, elementType);
+	    else
+		subclass = makeSubclass(pool, elementType);
+
+	    CtClass[] results = { subclass, pool.get(vec) };
+	    return results;
+	}
+	catch (NotFoundException e) {
+	    throw new CannotCompileException(e);
+	}
+	catch (IOException e) {
+	    throw new CannotCompileException(e);
+	}
+    }
+
+    /**
+     * Produces a new vector class.  This method does not work if
+     * the element type is a primitive type.
+     *
+     * @param type	the type of elements
+     */
+    public CtClass makeSubclass(ClassPool pool, CtClass type)
+	throws CannotCompileException, NotFoundException, IOException
+    {
+	CtClass vec = pool.makeClass(makeClassName(type));
+	vec.setSuperclass(pool.get("java.util.Vector"));
+
+	CtClass c = pool.get("sample.vector.Sample");
+	CtMethod addmethod = c.getDeclaredMethod("add");
+	CtMethod atmethod = c.getDeclaredMethod("at");
+
+	ClassMap map = new ClassMap();
+	map.put("sample.vector.X", type.getName());
+
+	vec.addMethod(CtNewMethod.copy(addmethod, "add", vec, map));
+	vec.addMethod(CtNewMethod.copy(atmethod, "at", vec, map));
+	vec.writeFile();
+	return vec;
+    }
+
+    /**
+     * Produces a new vector class.  This uses wrapped methods so that
+     * the element type can be a primitive type.
+     *
+     * @param type	the type of elements
+     */
+    public CtClass makeSubclass2(ClassPool pool, CtClass type)
+	throws CannotCompileException, NotFoundException, IOException
+    {
+	CtClass vec = pool.makeClass(makeClassName(type));
+	vec.setSuperclass(pool.get("java.util.Vector"));
+
+	CtClass c = pool.get("sample.vector.Sample2");
+	CtMethod addmethod = c.getDeclaredMethod("add");
+	CtMethod atmethod = c.getDeclaredMethod("at");
+
+	CtClass[] args1 = { type };
+	CtClass[] args2 = { CtClass.intType };
+	CtMethod m
+	    = CtNewMethod.wrapped(CtClass.voidType, "add", args1,
+				  null, addmethod, null, vec);
+	vec.addMethod(m);
+	m = CtNewMethod.wrapped(type, "at", args2,
+				null, atmethod, null, vec);
+	vec.addMethod(m);
+	vec.writeFile();
+	return vec;
+    }
+
+    private String makeClassName(CtClass type) {
+	return packageName + type.getSimpleName() + "Vector";
+    }
+}