How to use

WeakList

in

rocks.inspectit.agent.java.util

/**
 * Calling this method removes all the garbage collected elements in this list which appear to
 * be null now.<br>
 * TODO: call this method periodically!
 */
public void removeAllNullElements() {
  for (int i = size() - 1; i >= 0; i--) {
    if (get(i) == null) {
      remove(i);
    }
  }
}

/**
 * {@inheritDoc}
 */
@Override
public T get(int index) {
  return getHardReference(refs.get(index));
}

/**
 * {@inheritDoc}
 */
@Override
public boolean contains(Object o) {
  for (int i = 0; i < size(); i++) {
    if (o == get(i)) {
      return true;
    }
  }
  return false;
}

@Test
public void oneElement() {
  Object object = new Object();
  weakList.add(object);
  Object returnValue = weakList.get(0);
  assertThat(returnValue, is(notNullValue()));
  assertThat(returnValue, is(object));
}

@Test
public void clearNoGC() {
  Object objectOne = new Object();
  Object objectTwo = new Object();
  Object objectThree = new Object();
  weakList.add(objectOne);
  weakList.add(objectTwo);
  weakList.add(objectThree);
  weakList.clear();
  assertThat(weakList, is(empty()));
}

@Test(expectedExceptions = { IndexOutOfBoundsException.class })
public void outOfBounds() {
  assertThat(weakList.get(5), is(nullValue()));
}

@Test
public void containsNoGC() {
  Object objectOne = new Object();
  Object objectTwo = new Object();
  weakList.add(objectOne);
  weakList.add(objectTwo);
  assertThat(weakList, hasItem(objectTwo));
}

@BeforeMethod
public void initTestClass() {
  weakList = new WeakList<Object>();
}

/**
 * Returns a list of hard references. Skips all weak references but doesn't delete them if there
 * are any. The list returned (especially the indices) aren't the same as the ones from this
 * list.
 *
 * @return An {@link ArrayList} containing all the hard references of this weak list.
 */
public List<T> getHardReferences() {
  List<T> result = new ArrayList<T>();
  for (int i = 0; i < size(); i++) {
    T tmp = get(i);
    if (null != tmp) {
      result.add(tmp);
    }
  }
  return result;
}

@Test
public void clearWithGC() {
  Object objectOne = new Object();
  Object objectTwo = new Object();
  Object objectThree = new Object();
  weakList.add(objectOne);
  weakList.add(objectTwo);
  weakList.add(objectThree);
  System.gc();
  weakList.clear();
  assertThat(weakList, is(empty()));
}

@Test
public void containsWithGC() {
  Object objectOne = new Object();
  Object objectTwo = new Object();
  weakList.add(objectOne);
  weakList.add(objectTwo);
  System.gc();
  assertThat(weakList, hasItem(objectTwo));
}

/**
 * {@inheritDoc}
 */
@Override
public T remove(int index) {
  return getHardReference(refs.remove(index));
}

/**
 * {@inheritDoc}
 */
@Override
public T set(int index, T element) {
  return getHardReference(refs.set(index, new SoftReference<T>(element)));
}