/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package com.googlecode.openbeans;

import com.googlecode.openbeans.Encoder;
import com.googlecode.openbeans.Expression;
import com.googlecode.openbeans.PersistenceDelegate;
import java.lang.reflect.Field;

class ClassPersistenceDelegate extends PersistenceDelegate {
    @Override
    protected Expression instantiate(Object oldInstance, Encoder out) {
        Class<?> value = (Class<?>) oldInstance;
        Field fld = null;
        final String TYPE = "TYPE"; //$NON-NLS-1$
        Expression result;
        /*
         * Special treatment to String.class to prevent endless loop of
         * instantiation.
         */
        if (value == String.class) {
            return new Expression(value, "", "getClass", null); //$NON-NLS-1$//$NON-NLS-2$
        }
        try {
            if (value.equals(Integer.TYPE)) {
                fld = Integer.class.getField(TYPE);
            } else if (value.equals(Short.TYPE)) {
                fld = Short.class.getField(TYPE);
            } else if (value.equals(Long.TYPE)) {
                fld = Long.class.getField(TYPE);
            } else if (value.equals(Float.TYPE)) {
                fld = Float.class.getField(TYPE);
            } else if (value.equals(Double.TYPE)) {
                fld = Double.class.getField(TYPE);
            } else if (value.equals(Byte.TYPE)) {
                fld = Byte.class.getField(TYPE);
            } else if (value.equals(Character.TYPE)) {
                fld = Character.class.getField(TYPE);
            } else if (value.equals(Boolean.TYPE)) {
                fld = Boolean.class.getField(TYPE);
            }
        } catch (NoSuchFieldException e) {
            // impossible situation for valid java.lang classes
            // implementation with version >= 1.1
            throw new AssertionError(e);
        }
        if (fld != null) {
            // we have primitive type
            result = new Expression(oldInstance, fld,
                    "get", new Object[] { null }); //$NON-NLS-1$
        } else {
            result = new Expression(oldInstance, String.class, "forName", //$NON-NLS-1$ 
                    new Object[] { value.getName() });
        }
        return result;
    }

    @Override
    /*
     * It's unnecessary to do anything for initialization, because two mutatable
     * class objects are actually the same.
     */
    protected void initialize(Class<?> type, Object oldInstance,
            Object newInstance, Encoder out) {
        // do nothing
    }

    @Override
    protected boolean mutatesTo(Object oldInstance, Object newInstance) {
        if (oldInstance instanceof Class<?> && newInstance instanceof Class<?>) {
            Class<?> c1 = (Class<?>) oldInstance;
            Class<?> c2 = (Class<?>) newInstance;
            if (c1.getName().equals(c2.getName())) {
                return true;
            }
            return false;
        }
        return super.mutatesTo(oldInstance, newInstance);
    }
}