UtilMapPersistenceDelegate.java :  » Apache-Harmony-Java-SE » java-package » java » beans » Java Open Source

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java package » java » beans » UtilMapPersistenceDelegate.java
/*
 *  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 java.beans;

import java.util.Iterator;
import java.util.Map;
import java.util.Set;

class UtilMapPersistenceDelegate extends DefaultPersistenceDelegate {
    @Override
  @SuppressWarnings({ "unchecked", "nls" })
    protected void initialize(Class<?> type, Object oldInstance,
      Object newInstance, Encoder enc) {
    // Call the initialization of the super type
    super.initialize(type, oldInstance, newInstance, enc);

    Map map = (Map) oldInstance;
    Set keySet = map.keySet();
    for (Iterator i = keySet.iterator(); i.hasNext();) {
      Object key = i.next();
      Expression getterExp = new Expression(oldInstance, "get",
          new Object[] { key});
      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[] { key }).getValue();
        } catch (ArrayIndexOutOfBoundsException 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, "put",
                new Object[] { key, null });
            enc.writeStatement(setterStm);
          }
        } else {
          PersistenceDelegate pd = enc
              .getPersistenceDelegate(targetVal.getClass());
          if (!pd.mutatesTo(targetVal, newVal)) {
            Statement setterStm = new Statement(oldInstance, "put",
                new Object[] { key, oldVal });
            enc.writeStatement(setterStm);
          }
        }
      } catch (Exception ex) {
        enc.getExceptionListener().exceptionThrown(ex);
      }
    }
  }
}
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