Android Open Source - retention-magic Persistence Helper

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License

The source code is released under:
Apache License
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Java Source Code

/*
 * Copyright (C) 2013 Marten Gajda <marten@dmfs.org>
 */*  www  . ja va 2s  . com*/
 * Licensed 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 org.dmfs.android.retentionmagic;

import java.lang.reflect.Field;

import android.content.SharedPreferences;
import android.os.Bundle;


/**
 * A helper to store values of certain types in a Bundle or the SharedPreferences or to load them.
 * 
 * @author Marten Gajda <marten@dmfs.org>
 */
abstract class PersistenceHelper
{
  /**
   * Store a field in the given {@link Bundle}.
   * 
   * @param field
   *            The Field definition.
   * @param instance
   *            The class instance.
   * @param key
   *            The key of the value to restore.
   * @param bundle
   *            The {@link Bundle}.
   * @throws IllegalAccessException
   */
  public abstract void storeInBundle(Field field, Object instance, String key, Bundle bundle) throws IllegalAccessException;


  /**
   * Restore a field from the given {@link Bundle}.
   * 
   * @param field
   *            The Field definition.
   * @param instance
   *            The class instance.
   * @param key
   *            The key of the value to restore.
   * @param bundle
   *            The {@link Bundle}.
   * @throws IllegalAccessException
   */
  public abstract void restoreFromBundle(Field field, Object instance, String key, Bundle bundle) throws IllegalAccessException;


  /**
   * Store a field in the given {@link SharedPreferences.Editor}.
   * 
   * @param field
   *            The Field definition.
   * @param instance
   *            The class instance.
   * @param key
   *            The key of the value to restore.
   * @param editor
   *            The {@link SharedPreferences.Editor}.
   * @throws IllegalAccessException
   */
  public void storeInPreferences(Field field, Object instance, String key, SharedPreferences.Editor editor) throws IllegalAccessException
  {
    // most field don't support that
    throw new UnsupportedOperationException("saving of type " + field.getClass().getCanonicalName() + " in preferences is not supported");
  }


  /**
   * Restore a field from the given {@link SharedPreferences}.
   * 
   * @param field
   *            The Field definition.
   * @param instance
   *            The class instance.
   * @param key
   *            The key of the value to restore.
   * @param prefs
   *            The {@link SharedPreferences}.
   * @throws IllegalAccessException
   */
  public void restoreFromPreferences(Field field, Object instance, String key, SharedPreferences prefs) throws IllegalAccessException
  {
    // most field don't support that
    throw new UnsupportedOperationException("loading of type " + field.getClass().getCanonicalName() + " from preferences not supported");
  }
}
Java Source Code List
