| /******************************************************************************* |
| * Copyright (c) 2009, 2010 IBM Corporation and others. |
| * |
| * This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License 2.0 |
| * which accompanies this distribution, and is available at |
| * https://www.eclipse.org/legal/epl-2.0/ |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.e4.core.internal.di; |
| |
| import java.lang.ref.WeakReference; |
| import java.util.*; |
| |
| /** |
| * A list that holds weak references to the objects. |
| */ |
| public class WeakRefList { |
| |
| private List<WeakReference<?>> userObjects; |
| |
| public WeakRefList(int initialSize) { |
| userObjects = new ArrayList<>(initialSize); |
| } |
| |
| public Object[] getSafeCopy() { |
| Object[] result; |
| int pos = 0; |
| synchronized (userObjects) { |
| result = new Object[userObjects.size()]; |
| for (Iterator<WeakReference<?>> i = userObjects.iterator(); i.hasNext();) { |
| WeakReference<?> ref = i.next(); |
| Object userObject = ref.get(); |
| if (userObject == null) { |
| // user object got GCed, clean up refs for future |
| i.remove(); |
| continue; |
| } |
| result[pos] = userObject; |
| pos++; |
| } |
| } |
| if (pos == result.length) |
| return result; |
| // reallocate the array |
| Object[] tmp = new Object[pos]; |
| System.arraycopy(result, 0, tmp, 0, pos); |
| return tmp; |
| } |
| |
| public void add(Object object) { |
| WeakReference<?> ref = new WeakReference<>(object); |
| synchronized (userObjects) { |
| userObjects.add(ref); |
| } |
| } |
| |
| public boolean remove(Object object) { |
| synchronized (userObjects) { |
| for (Iterator<WeakReference<?>> i = userObjects.iterator(); i.hasNext();) { |
| WeakReference<?> ref = i.next(); |
| Object userObject = ref.get(); |
| if (userObject == null) { |
| i.remove(); |
| continue; |
| } |
| if (userObject == object) { // use pointer comparison |
| i.remove(); |
| return true; |
| } |
| } |
| return false; |
| } |
| } |
| } |