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/*
 *  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 lite.beans;

import java.util.List;

class UtilListPersistenceDelegate extends DefaultPersistenceDelegate {
    @Override
    @SuppressWarnings({ "nls", "boxing" })
    protected void initialize(Class type, Object oldInstance,
            Object newInstance, Encoder enc) {

        List list = (List) oldInstance;
        int size = list.size();
        for (int i = 0; i < size; i++) {
            Expression getterExp = new Expression(oldInstance, "get",
                    new Object[] { i });
            try {
                // Calculate the old value of the property
                Object oldVal = getterExp.getValue();
                // Write the getter expression to the encoder
                enc.writeExpression(getterExp);
                // Get the target value that exists in the new environment
                Object targetVal = enc.get(oldVal);
                // Get the current property value in the new environment
                Object newVal = null;
                try {
                    newVal = new Expression(newInstance, "get",
                        new Object[] { i }).getValue();
                } catch (IndexOutOfBoundsException ex) {
                    // The newInstance has no elements, so current property
                    // value remains null
                }
                /*
                 * Make the target value and current property value equivalent
                 * in the new environment
                 */
                if (null == targetVal) {
                    if (null != newVal) {
                        // Set to null
                        Statement setterStm = new Statement(oldInstance, "add",
                                new Object[] { null });
                        enc.writeStatement(setterStm);
                    }
                } else {
                    PersistenceDelegate pd = enc
                            .getPersistenceDelegate(targetVal.getClass());
                    if (!pd.mutatesTo(targetVal, newVal)) {
                        Statement setterStm = new Statement(oldInstance, "add",
                                new Object[] { oldVal });
                        enc.writeStatement(setterStm);
                    }
                }
            } catch (Exception ex) {
                enc.getExceptionListener().exceptionThrown(ex);
            }
        }
    }
}