javassist/src/main/javassist/CtField.java

/*
 * Javassist, a Java-bytecode translator toolkit.
 * Copyright (C) 1999-2003 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 javassist.bytecode.*;
import javassist.compiler.Javac;
import javassist.compiler.CompileError;
import javassist.compiler.ast.ASTree;

/**
 * An instance of CtField represents a field.
 *
 * @see CtClass#getDeclaredFields()
 */
public class CtField extends CtMember {
    protected FieldInfo fieldInfo;
    CtField next;

    /**
     * Creates a <code>CtField</code> object.
     * The created field must be added to a class
     * with <code>CtClass.addField()</code>.
     * An initial value of the field is specified
     * by a <code>CtField.Initializer</code> object.
     *
     * <p>If getter and setter methods are needed,
     * call <code>CtNewMethod.getter()</code> and 
     * <code>CtNewMethod.setter()</code>.
     *
     * @param type              field type
     * @param name              field name
     * @param declaring         the class to which the field will be added.
     *
     * @see CtClass#addField(CtField)
     * @see CtNewMethod#getter(String,CtField)
     * @see CtNewMethod#setter(String,CtField)
     * @see CtField.Initializer
     */
    public CtField(CtClass type, String name, CtClass declaring)
        throws CannotCompileException
    {
        this(Descriptor.of(type), name, declaring);
    }

    /**
     * Creates a copy of the given field.
     * The created field must be added to a class
     * with <code>CtClass.addField()</code>.
     * An initial value of the field is specified
     * by a <code>CtField.Initializer</code> object.
     *
     * <p>If getter and setter methods are needed,
     * call <code>CtNewMethod.getter()</code> and 
     * <code>CtNewMethod.setter()</code>.
     *
     * @param src               the original field
     * @param declaring         the class to which the field will be added.
     * @see CtNewMethod#getter(String,CtField)
     * @see CtNewMethod#setter(String,CtField)
     * @see CtField.Initializer
     */
    public CtField(CtField src, CtClass declaring)
        throws CannotCompileException
    {
        this(src.fieldInfo.getDescriptor(), src.fieldInfo.getName(),
             declaring);
    }

    private CtField(String typeDesc, String name, CtClass clazz)
        throws CannotCompileException
    {
        super(clazz);
        next = null;
        ClassFile cf = clazz.getClassFile2();
        if (cf == null)
            throw new CannotCompileException("bad declaring class: "
                                             + clazz.getName());

        fieldInfo = new FieldInfo(cf.getConstPool(), name, typeDesc);
    }

    CtField(FieldInfo fi, CtClass clazz) {
        super(clazz);
        fieldInfo = fi;
        next = null;
    }

    /* Javac.CtFieldWithInit overrides.
     */
    protected ASTree getInitAST() { return null; }

    /* Called by CtClassType.addField().
     */
    Initializer getInit() {
        ASTree tree = getInitAST();
        if (tree == null)
            return null;
        else
            return Initializer.byExpr(tree);
    }

    /**
     * Compiles the given source code and creates a field.
     * Examples of the source code are:
     *
     * <ul><pre>
     * "public String name;"
     * "public int k = 3;"</pre></ul>
     *
     * <p>Note that the source code ends with <code>';'</code>
     * (semicolon).
     *
     * @param src               the source text.
     * @param declaring    the class to which the created field is added.
     */
    public static CtField make(String src, CtClass declaring)
        throws CannotCompileException
    {
        Javac compiler = new Javac(declaring);
        try {
            CtMember obj = compiler.compile(src);
            if (obj instanceof CtField)
                return (CtField)obj; // an instance of Javac.CtFieldWithInit
        }
        catch (CompileError e) {
            throw new CannotCompileException(e);
        }

        throw new CannotCompileException("not a field");
    }

    static CtField append(CtField list, CtField tail) {
        tail.next = null;
        if (list == null)
            return tail;
        else {
            CtField lst = list;
            while (lst.next != null)
                lst = lst.next;

            lst.next = tail;
            return list;
        }
    }

    static int count(CtField f) {
        int n = 0;
        while (f != null) {
            ++n;
            f = f.next;
        }

        return n;
    }

    /**
     * Returns the FieldInfo representing the field in the class file.
     */
    public FieldInfo getFieldInfo() {
        declaringClass.checkModify();
        return fieldInfo;
    }

    /**
     * Undocumented method.  Do not use; internal-use only.
     */
    public FieldInfo getFieldInfo2() { return fieldInfo; }

    /**
     * Returns the class declaring the field.
     */
    public CtClass getDeclaringClass() {
        // this is redundant but for javadoc.
        return super.getDeclaringClass();
    }

    /**
     * Returns the name of the field.
     */
    public String getName() {
        return fieldInfo.getName();
    }

    /**
     * Changes the name of the field.
     */
    public void setName(String newName) {
        fieldInfo.setName(newName);
    }

    /**
     * Returns the encoded modifiers of the field.
     *
     * @see Modifier
     */
    public int getModifiers() {
        return AccessFlag.toModifier(fieldInfo.getAccessFlags());
    }

    /**
     * Sets the encoded modifiers of the field.
     *
     * @see Modifier
     */
    public void setModifiers(int mod) {
        fieldInfo.setAccessFlags(AccessFlag.of(mod));
    }

    /**
     * Returns the type of the field.
     */
    public CtClass getType() throws NotFoundException {
        return Descriptor.toCtClass(fieldInfo.getDescriptor(),
                                    declaringClass.getClassPool());
    }

    /**
     * Sets the type of the field.
     */
    public void setType(CtClass clazz) {
        declaringClass.checkModify();
        fieldInfo.setDescriptor(Descriptor.of(clazz));
    }

    /**
     * Obtains an attribute with the given name.
     * If that attribute is not found in the class file, this
     * method returns null.
     *
     * @param name              attribute name
     */
    public byte[] getAttribute(String name) {
        AttributeInfo ai = fieldInfo.getAttribute(name);
        if (ai == null)
            return null;
        else
            return ai.get();
    }

    /**
     * Adds an attribute. The attribute is saved in the class file.
     *
     * @param name      attribute name
     * @param data      attribute value
     */
    public void setAttribute(String name, byte[] data) {
        declaringClass.checkModify();
        fieldInfo.addAttribute(new AttributeInfo(fieldInfo.getConstPool(),
                                                 name, data));
    }

    // inner classes

    /**
     * Instances of this class specify how to initialize a field.
     * <code>Initializer</code> is passed to
     * <code>CtClass.addField()</code> with a <code>CtField</code>.
     *
     * <p>This class cannot be instantiated with the <code>new</code> operator.
     * Factory methods such as <code>byParameter()</code> and
     * <code>byNew</code>
     * must be used for the instantiation.  They create a new instance with
     * the given parameters and return it.
     *
     * @see CtClass#addField(CtField,CtField.Initializer)
     */
    public static abstract class Initializer {
        /**
         * Makes an initializer that assigns a constant integer value.
         * The field must be integer type.
         */
        public static Initializer constant(int i) {
            return new IntInitializer(i);
        }

        /**
         * Makes an initializer that assigns a constant long value.
         * The field must be long type.
         */
        public static Initializer constant(long l) {
            return new LongInitializer(l);
        }

        /**
         * Makes an initializer that assigns a constant double value.
         * The field must be double type.
         */
        public static Initializer constant(double d) {
            return new DoubleInitializer(d);
        }

        /**
         * Makes an initializer that assigns a constant string value.
         * The field must be <code>java.lang.String</code> type.
         */
        public static Initializer constant(String s) {
            return new StringInitializer(s);
        }

        /**
         * Makes an initializer using a constructor parameter.
         *
         * <p>The initial value is the
         * N-th parameter given to the constructor of the object including
         * the field.  If the constructor takes less than N parameters,
         * the field is not initialized.
         * If the field is static, it is never initialized.
         *
         * @param nth           the n-th (&gt;= 0) parameter is used as
         *                      the initial value.
         *                      If nth is 0, then the first parameter is
         *                      used.
         */
        public static Initializer byParameter(int nth) {
            ParamInitializer i = new ParamInitializer();
            i.nthParam = nth;
            return i;
        }

        /**
         * Makes an initializer creating a new object.
         *
         * <p>This initializer creates a new object and uses it as the initial
         * value of the field.  The constructor of the created object receives
         * the parameter:
         *
         * <ul><code>Object obj</code> - the object including the field.<br>
         * </ul>
         *
         * <p>If the initialized field is static, then the constructor does
         * not receive any parameters.
         *
         * @param objectType    the class instantiated for the initial value.
         */
        public static Initializer byNew(CtClass objectType) {
            NewInitializer i = new NewInitializer();
            i.objectType = objectType;
            i.stringParams = null;
            i.withConstructorParams = false;
            return i;
        }

        /**
         * Makes an initializer creating a new object.
         *
         * <p>This initializer creates a new object and uses it as the initial
         * value of the field.  The constructor of the created object receives
         * the parameters:
         *
         * <ul><code>Object obj</code> - the object including the field.<br>
         *     <code>String[] strs</code> - the character strings specified
         *                              by <code>stringParams</code><br>
         * </ul>
         *
         * <p>If the initialized field is static, then the constructor
         * receives only <code>strs</code>.
         *
         * @param objectType    the class instantiated for the initial value.
         * @param stringParams  the array of strings passed to the
         *                      constructor.
         */
        public static Initializer byNew(CtClass objectType,
                                             String[] stringParams) {
            NewInitializer i = new NewInitializer();
            i.objectType = objectType;
            i.stringParams = stringParams;
            i.withConstructorParams = false;
            return i;
        }

        /**
         * Makes an initializer creating a new object.
         *
         * <p>This initializer creates a new object and uses it as the initial
         * value of the field.  The constructor of the created object receives
         * the parameters:
         *
         * <ul><code>Object obj</code> - the object including the field.<br>
         *     <code>Object[] args</code> - the parameters passed to the
         *                      constructor of the object including the
         *                      filed.
         * </ul>
         *
         * <p>If the initialized field is static, then the constructor does
         * not receive any parameters.
         *
         * @param objectType    the class instantiated for the initial value.
         *
         * @see javassist.CtField.Initializer#byNewArray(CtClass,int)
         * @see javassist.CtField.Initializer#byNewArray(CtClass,int[])
         */
        public static Initializer byNewWithParams(CtClass objectType) {
            NewInitializer i = new NewInitializer();
            i.objectType = objectType;
            i.stringParams = null;
            i.withConstructorParams = true;
            return i;
        }

        /**
         * Makes an initializer creating a new object.
         *
         * <p>This initializer creates a new object and uses it as the initial
         * value of the field.  The constructor of the created object receives
         * the parameters:
         *
         * <ul><code>Object obj</code> - the object including the field.<br>
         *     <code>String[] strs</code> - the character strings specified
         *                              by <code>stringParams</code><br>
         *     <code>Object[] args</code> - the parameters passed to the
         *                      constructor of the object including the
         *                      filed.
         * </ul>
         *
         * <p>If the initialized field is static, then the constructor receives
         * only <code>strs</code>.
         *
         * @param objectType    the class instantiated for the initial value.
         * @param stringParams  the array of strings passed to the
         *                              constructor.
         */
        public static Initializer byNewWithParams(CtClass objectType,
                                               String[] stringParams) {
            NewInitializer i = new NewInitializer();
            i.objectType = objectType;
            i.stringParams = stringParams;
            i.withConstructorParams = true;
            return i;
        }

        /**
         * Makes an initializer calling a static method.
         *
         * <p>This initializer calls a static method and uses the returned
         * value as the initial value of the field.
         * The called method receives the parameters:
         *
         * <ul><code>Object obj</code> - the object including the field.<br>
         * </ul>
         *
         * <p>If the initialized field is static, then the method does
         * not receive any parameters.
         *
         * <p>The type of the returned value must be the same as the field
         * type.
         *
         * @param methodClass   the class that the static method is
         *                              declared in.
         * @param methodName    the name of the satic method.
         */
        public static Initializer byCall(CtClass methodClass,
                                              String methodName) {
            MethodInitializer i = new MethodInitializer();
            i.objectType = methodClass;
            i.methodName = methodName;
            i.stringParams = null;
            i.withConstructorParams = false;
            return i;
        }

        /**
         * Makes an initializer calling a static method.
         *
         * <p>This initializer calls a static method and uses the returned
         * value as the initial value of the field.  The called method
         * receives the parameters:
         *
         * <ul><code>Object obj</code> - the object including the field.<br>
         *     <code>String[] strs</code> - the character strings specified
         *                              by <code>stringParams</code><br>
         * </ul>
         *
         * <p>If the initialized field is static, then the method
         * receive only <code>strs</code>.
         *
         * <p>The type of the returned value must be the same as the field
         * type.
         *
         * @param methodClass   the class that the static method is
         *                              declared in.
         * @param methodName    the name of the satic method.
         * @param stringParams  the array of strings passed to the
         *                              static method.
         */
        public static Initializer byCall(CtClass methodClass,
                                              String methodName,
                                              String[] stringParams) {
            MethodInitializer i = new MethodInitializer();
            i.objectType = methodClass;
            i.methodName = methodName;
            i.stringParams = stringParams;
            i.withConstructorParams = false;
            return i;
        }

        /**
         * Makes an initializer calling a static method.
         *
         * <p>This initializer calls a static method and uses the returned
         * value as the initial value of the field.  The called method
         * receives the parameters:
         *
         * <ul><code>Object obj</code> - the object including the field.<br>
         *     <code>Object[] args</code> - the parameters passed to the
         *                      constructor of the object including the
         *                      filed.
         * </ul>
         *
         * <p>If the initialized field is static, then the method does
         * not receive any parameters.
         *
         * <p>The type of the returned value must be the same as the field
         * type.
         *
         * @param methodClass   the class that the static method is
         *                              declared in.
         * @param methodName    the name of the satic method.
         */
        public static Initializer byCallWithParams(CtClass methodClass,
                                                        String methodName) {
            MethodInitializer i = new MethodInitializer();
            i.objectType = methodClass;
            i.methodName = methodName;
            i.stringParams = null;
            i.withConstructorParams = true;
            return i;
        }

        /**
         * Makes an initializer calling a static method.
         *
         * <p>This initializer calls a static method and uses the returned
         * value as the initial value of the field.  The called method
         * receives the parameters:
         *
         * <ul><code>Object obj</code> - the object including the field.<br>
         *     <code>String[] strs</code> - the character strings specified
         *                              by <code>stringParams</code><br>
         *     <code>Object[] args</code> - the parameters passed to the
         *                      constructor of the object including the
         *                      filed.
         * </ul>
         *
         * <p>If the initialized field is static, then the method
         * receive only <code>strs</code>.
         *
         * <p>The type of the returned value must be the same as the field
         * type.
         *
         * @param methodClass   the class that the static method is
         *                              declared in.
         * @param methodName    the name of the satic method.
         * @param stringParams  the array of strings passed to the
         *                              static method.
         */
        public static Initializer byCallWithParams(CtClass methodClass,
                                String methodName, String[] stringParams) {
            MethodInitializer i = new MethodInitializer();
            i.objectType = methodClass;
            i.methodName = methodName;
            i.stringParams = stringParams;
            i.withConstructorParams = true;
            return i;
        }

        /**
         * Makes an initializer creating a new array.
         *
         * @param type  the type of the array.
         * @param size  the size of the array.
         * @throws NotFoundException    if the type of the array components
         *                              is not found.
         */
        public static Initializer byNewArray(CtClass type, int size) 
            throws NotFoundException
        {
            return new ArrayInitializer(type.getComponentType(), size);
        }

        /**
         * Makes an initializer creating a new multi-dimensional array.
         *
         * @param type  the type of the array.
         * @param sizes an <code>int</code> array of the size in every
         *                      dimension.
         *                      The first element is the size in the first
         *                      dimension.  The second is in the second, etc.
         */
        public static Initializer byNewArray(CtClass type, int[] sizes) {
            return new MultiArrayInitializer(type, sizes);
        }

        /**
         * Makes an initializer.
         *
         * @param source        initializer expression.
         */
        public static Initializer byExpr(String source) {
            return new CodeInitializer(source);
        }

        static Initializer byExpr(ASTree source) {
            return new PtreeInitializer(source);
        }

        // Check whether this initializer is valid for the field type.
        // If it is invaild, this method throws an exception.
        void check(CtClass type) throws CannotCompileException {}

        // produce codes for initialization
        abstract int compile(CtClass type, String name, Bytecode code,
                             CtClass[] parameters, Javac drv)
            throws CannotCompileException;

        // produce codes for initialization
        abstract int compileIfStatic(CtClass type, String name,
                Bytecode code, Javac drv) throws CannotCompileException;
    }

    static abstract class CodeInitializer0 extends Initializer {
        abstract void compileExpr(Javac drv) throws CompileError;

        int compile(CtClass type, String name, Bytecode code,
                    CtClass[] parameters, Javac drv)
            throws CannotCompileException
        {
            try {
                code.addAload(0);
                compileExpr(drv);
                code.addPutfield(Bytecode.THIS, name, Descriptor.of(type));
                return code.getMaxStack();
            }
            catch (CompileError e) {
                throw new CannotCompileException(e);
            }
        }

        int compileIfStatic(CtClass type, String name, Bytecode code,
                            Javac drv) throws CannotCompileException
        {
            try {
                compileExpr(drv);
                code.addPutstatic(Bytecode.THIS, name, Descriptor.of(type));
                return code.getMaxStack();
            }
            catch (CompileError e) {
                throw new CannotCompileException(e);
            }
        }
    }

    static class CodeInitializer extends CodeInitializer0 {
        private String expression;

        CodeInitializer(String expr) { expression = expr; }

        void compileExpr(Javac drv) throws CompileError {
            drv.compileExpr(expression);
        }
    }

    static class PtreeInitializer extends CodeInitializer0 {
        private ASTree expression;

        PtreeInitializer(ASTree expr) { expression = expr; }

        void compileExpr(Javac drv) throws CompileError {
            drv.compileExpr(expression);
        }
    }

    /**
     * A field initialized with a parameter passed to the constructor
     * of the class containing that field.
     */
    static class ParamInitializer extends Initializer {
        int nthParam;

        ParamInitializer() {}

        int compile(CtClass type, String name, Bytecode code,
                    CtClass[] parameters, Javac drv)
            throws CannotCompileException
        {
            if (parameters != null && nthParam < parameters.length) {
                code.addAload(0);
                int nth = nthParamToLocal(nthParam, parameters, false);
                int s = code.addLoad(nth, type) + 1;
                code.addPutfield(Bytecode.THIS, name, Descriptor.of(type));
                return s;       // stack size
            }
            else
                return 0;       // do not initialize
        }

        /**
         * Computes the index of the local variable that the n-th parameter
         * is assigned to.
         *
         * @param nth           n-th parameter
         * @param params                list of parameter types
         * @param isStatic              true if the method is static.
         */
        static int nthParamToLocal(int nth, CtClass[] params,
                                   boolean isStatic) {
            CtClass longType = CtClass.longType;
            CtClass doubleType = CtClass.doubleType;
            int k;
            if (isStatic)
                k = 0;
            else
                k = 1;  // 0 is THIS.

            for (int i = 0; i < nth; ++i) {
                CtClass type = params[i];
                if (type == longType || type == doubleType)
                    k += 2;
                else
                    ++k;
            }

            return k;
        }

        int compileIfStatic(CtClass type, String name, Bytecode code,
                            Javac drv) throws CannotCompileException
        {
            return 0;
        }
    }

    /**
     * A field initialized with an object created by the new operator.
     */
    static class NewInitializer extends Initializer {
        CtClass objectType;
        String[] stringParams;
        boolean withConstructorParams;

        NewInitializer() {}

        /**
         * Produces codes in which a new object is created and assigned to
         * the field as the initial value.
         */
        int compile(CtClass type, String name, Bytecode code,
                    CtClass[] parameters, Javac drv)
            throws CannotCompileException
        {
            int stacksize;

            code.addAload(0);
            code.addNew(objectType);
            code.add(Bytecode.DUP);
            code.addAload(0);

            if (stringParams == null)
                stacksize = 4;
            else
                stacksize = compileStringParameter(code) + 4;

            if (withConstructorParams)
                stacksize += CtNewWrappedMethod.compileParameterList(code,
                                                            parameters, 1);

            code.addInvokespecial(objectType, "<init>", getDescriptor());
            code.addPutfield(Bytecode.THIS, name, Descriptor.of(type));
            return stacksize;
        }

        private String getDescriptor() {
            final String desc3
        = "(Ljava/lang/Object;[Ljava/lang/String;[Ljava/lang/Object;)V";

            if (stringParams == null)
                if (withConstructorParams)
                    return "(Ljava/lang/Object;[Ljava/lang/Object;)V";
                else
                    return "(Ljava/lang/Object;)V";
            else
                if (withConstructorParams)
                    return desc3;
                else
                    return "(Ljava/lang/Object;[Ljava/lang/String;)V";
        }

        /**
         * Produces codes for a static field.
         */
        int compileIfStatic(CtClass type, String name, Bytecode code,
                            Javac drv) throws CannotCompileException
        {
            String desc;

            code.addNew(objectType);
            code.add(Bytecode.DUP);

            int stacksize = 2;
            if (stringParams == null)
                desc = "()V";
            else {
                desc = "([Ljava/lang/String;)V";
                stacksize += compileStringParameter(code);
            }

            code.addInvokespecial(objectType, "<init>", desc);
            code.addPutstatic(Bytecode.THIS, name, Descriptor.of(type));
            return stacksize;
        }

        protected final int compileStringParameter(Bytecode code)
            throws CannotCompileException
        {
            int nparam = stringParams.length;
            code.addIconst(nparam);
            code.addAnewarray("java.lang.String");
            for (int j = 0; j < nparam; ++j) {
                code.add(Bytecode.DUP);         // dup
                code.addIconst(j);                      // iconst_<j>
                code.addLdc(stringParams[j]);   // ldc ...
                code.add(Bytecode.AASTORE);             // aastore
            }

            return 4;
        }

    }

    /**
     * A field initialized with the result of a static method call.
     */
    static class MethodInitializer extends NewInitializer {
        String methodName;
        // the method class is specified by objectType.

        MethodInitializer() {}

        /**
         * Produces codes in which a new object is created and assigned to
         * the field as the initial value.
         */
        int compile(CtClass type, String name, Bytecode code,
                    CtClass[] parameters, Javac drv)
            throws CannotCompileException
        {
            int stacksize;

            code.addAload(0);
            code.addAload(0);

            if (stringParams == null)
                stacksize = 2;
            else
                stacksize = compileStringParameter(code) + 2;

            if (withConstructorParams)
                stacksize += CtNewWrappedMethod.compileParameterList(code,
                                                            parameters, 1);

            String typeDesc = Descriptor.of(type);
            String mDesc = getDescriptor() + typeDesc;
            code.addInvokestatic(objectType, methodName, mDesc);
            code.addPutfield(Bytecode.THIS, name, typeDesc);
            return stacksize;
        }

        private String getDescriptor() {
            final String desc3
                = "(Ljava/lang/Object;[Ljava/lang/String;[Ljava/lang/Object;)";

            if (stringParams == null)
                if (withConstructorParams)
                    return "(Ljava/lang/Object;[Ljava/lang/Object;)";
                else
                    return "(Ljava/lang/Object;)";
            else
                if (withConstructorParams)
                    return desc3;
                else
                    return "(Ljava/lang/Object;[Ljava/lang/String;)";
        }

        /**
         * Produces codes for a static field.
         */
        int compileIfStatic(CtClass type, String name, Bytecode code,
                            Javac drv) throws CannotCompileException
        {
            String desc;

            int stacksize = 1;
            if (stringParams == null)
                desc = "()";
            else {
                desc = "([Ljava/lang/String;)";
                stacksize += compileStringParameter(code);
            }

            String typeDesc = Descriptor.of(type);
            code.addInvokestatic(objectType, methodName, desc + typeDesc);
            code.addPutstatic(Bytecode.THIS, name, typeDesc);
            return stacksize;
        }
    }

    static class IntInitializer extends Initializer {
        int value;

        IntInitializer(int v) { value = v; }

        void check(CtClass type) throws CannotCompileException {
            if (type != CtClass.intType)
                throw new CannotCompileException("type mismatch");
        }

        int compile(CtClass type, String name, Bytecode code,
                    CtClass[] parameters, Javac drv)
            throws CannotCompileException
        {
            code.addAload(0);
            code.addIconst(value);
            code.addPutfield(Bytecode.THIS, name, Descriptor.of(type));
            return 2;   // stack size
        }

        int compileIfStatic(CtClass type, String name, Bytecode code,
                            Javac drv) throws CannotCompileException
        {
            code.addIconst(value);
            code.addPutstatic(Bytecode.THIS, name, Descriptor.of(type));
            return 1;   // stack size
        }
    }

    static class LongInitializer extends Initializer {
        long value;

        LongInitializer(long v) { value = v; }

        void check(CtClass type) throws CannotCompileException {
            if (type != CtClass.longType)
                throw new CannotCompileException("type mismatch");
        }

        int compile(CtClass type, String name, Bytecode code,
                    CtClass[] parameters, Javac drv)
            throws CannotCompileException
        {
            code.addAload(0);
            code.addLdc2w(value);
            code.addPutfield(Bytecode.THIS, name, Descriptor.of(type));
            return 3;   // stack size
        }

        int compileIfStatic(CtClass type, String name, Bytecode code,
                            Javac drv) throws CannotCompileException
        {
            code.addLdc2w(value);
            code.addPutstatic(Bytecode.THIS, name, Descriptor.of(type));
            return 2;   // stack size
        }
    }

    static class DoubleInitializer extends Initializer {
        double value;

        DoubleInitializer(double v) { value = v; }

        void check(CtClass type) throws CannotCompileException {
            if (type != CtClass.doubleType)
                throw new CannotCompileException("type mismatch");
        }

        int compile(CtClass type, String name, Bytecode code,
                    CtClass[] parameters, Javac drv)
            throws CannotCompileException
        {
            code.addAload(0);
            code.addLdc2w(value);
            code.addPutfield(Bytecode.THIS, name, Descriptor.of(type));
            return 3;   // stack size
        }

        int compileIfStatic(CtClass type, String name, Bytecode code,
                            Javac drv) throws CannotCompileException
        {
            code.addLdc2w(value);
            code.addPutstatic(Bytecode.THIS, name, Descriptor.of(type));
            return 2;   // stack size
        }
    }

    static class StringInitializer extends Initializer {
        String value;

        StringInitializer(String v) { value = v; }

        void check(CtClass type) throws CannotCompileException {
            if (!type.getName().equals("java.lang.String"))
                throw new CannotCompileException("type mismatch");
        }

        int compile(CtClass type, String name, Bytecode code,
                    CtClass[] parameters, Javac drv)
            throws CannotCompileException
        {
            code.addAload(0);
            code.addLdc(value);
            code.addPutfield(Bytecode.THIS, name, Descriptor.of(type));
            return 2;   // stack size
        }

        int compileIfStatic(CtClass type, String name, Bytecode code,
                            Javac drv) throws CannotCompileException
        {
            code.addLdc(value);
            code.addPutstatic(Bytecode.THIS, name, Descriptor.of(type));
            return 1;   // stack size
        }
    }

    static class ArrayInitializer extends Initializer {
        CtClass type;
        int size;

        ArrayInitializer(CtClass t, int s) { type = t; size = s; }

        private void addNewarray(Bytecode code) {
            if (type.isPrimitive())
                code.addNewarray(((CtPrimitiveType)type).getArrayType(),
                                 size);
            else
                code.addAnewarray(type, size);
        }

        int compile(CtClass type, String name, Bytecode code,
                    CtClass[] parameters, Javac drv)
            throws CannotCompileException
        {
            code.addAload(0);
            addNewarray(code);
            code.addPutfield(Bytecode.THIS, name, Descriptor.of(type));
            return 2;   // stack size
        }

        int compileIfStatic(CtClass type, String name, Bytecode code,
                            Javac drv) throws CannotCompileException
        {
            addNewarray(code);
            code.addPutstatic(Bytecode.THIS, name, Descriptor.of(type));
            return 1;   // stack size
        }
    }

    static class MultiArrayInitializer extends Initializer {
        CtClass type;
        int[] dim;

        MultiArrayInitializer(CtClass t, int[] d) { type = t; dim = d; }

        void check(CtClass type) throws CannotCompileException {
            if (!type.isArray())
                throw new CannotCompileException("type mismatch");
        }

        int compile(CtClass type, String name, Bytecode code,
                    CtClass[] parameters, Javac drv)
            throws CannotCompileException
        {
            code.addAload(0);
            int s = code.addMultiNewarray(type, dim);
            code.addPutfield(Bytecode.THIS, name, Descriptor.of(type));
            return s + 1;       // stack size
        }

        int compileIfStatic(CtClass type, String name, Bytecode code,
                            Javac drv) throws CannotCompileException
        {
            int s = code.addMultiNewarray(type, dim);
            code.addPutstatic(Bytecode.THIS, name, Descriptor.of(type));
            return s;   // stack size
        }
    }
}