/*
GNU LESSER GENERAL PUBLIC LICENSE
Copyright (C) 2006 The Lobo Project
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Contact info: lobochief@users.sourceforge.net
*/
package org.lobobrowser.js;
import java.lang.ref.WeakReference;
import java.util.Map;
import java.util.WeakHashMap;
public class JavaClassWrapperFactory {
private static JavaClassWrapperFactory instance;
private final Map<Class<?>, WeakReference<JavaClassWrapper>> classWrappers = new WeakHashMap<>();
private JavaClassWrapperFactory() {
}
public static JavaClassWrapperFactory getInstance() {
if (instance == null) {
synchronized (JavaClassWrapperFactory.class) {
if (instance == null) {
instance = new JavaClassWrapperFactory();
}
}
}
return instance;
}
public JavaClassWrapper getClassWrapper(final Class<?> clazz) {
synchronized (this) {
// WeakHashMaps where the value refers to
// the key will retain keys. Must make it
// refer to the value weakly too.
final WeakReference<?> jcwr = this.classWrappers.get(clazz);
JavaClassWrapper jcw = null;
if (jcwr != null) {
jcw = (JavaClassWrapper) jcwr.get();
}
if (jcw == null) {
// TODO: need to check with the class shutter here. GH #136
jcw = new JavaClassWrapper(clazz);
this.classWrappers.put(clazz, new WeakReference<>(jcw));
}
return jcw;
}
}
}