Android Open Source - task4java Indexed List

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License

The source code is released under:

Apache License

Java Source Code

/*
 *  Copyright (c) 2014 Andree Hagelstein, Maik Schulze, Deutsche Telekom AG. All Rights Reserved.
 *  /*ww w  .  jav a  2 s .c  o m*/
 *  Filename: IndexedList.java
 */

package com.task4java;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public abstract class IndexedList<K, V, L> extends ArrayList<L> {

  private static final long serialVersionUID = 1L;

  private Object _oLock = new Object();
  private HashMap<K, V> _keyItem = null;

  protected abstract Tuple<K, V> extractKeyValue(L item);

  public List<K> getAllKeys() {

    synchronized (_oLock) {

      List<K> allKeys = new ArrayList<K>();

      for (L item : this) {

        if (item != null) {

          allKeys.add(extractKeyValue(item).left);
        }
      }

      return allKeys;
    }
  }

  public V getItem(K key, V defaultValue) {

    synchronized (_oLock) {

      HashMap<K, V> keyItem = _keyItem;

      if (keyItem == null) {
        keyItem = new HashMap<K, V>();

        for (L item : this) {

          if (item != null) {

            Tuple<K, V> keyValue = extractKeyValue(item);

            keyItem.put(keyValue.left, keyValue.right);
          }
        }

        _keyItem = keyItem;
      }

      if (keyItem.containsKey(key)) {

        return keyItem.get(key);
      } else {

        return defaultValue;
      }
    }
  }

  public void refresh() {

    synchronized (_oLock) {
      _keyItem = null;
    }
  }
}

Java Source Code List

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