org.wicketstuff.lazymodel.reflect.CachingProxyFactory.java Source code

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Here is the source code for org.wicketstuff.lazymodel.reflect.CachingProxyFactory.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.wicketstuff.lazymodel.reflect;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.wicket.Application;
import org.apache.wicket.util.lang.Generics;

/**
 * A factory caching proxy classes.
 * 
 * @see #createClass(Class)
 */
public class CachingProxyFactory implements IProxyFactory {

    private final ConcurrentHashMap<Object, IProxyFactory> scopes = Generics.newConcurrentHashMap(2);

    private final IProxyFactory factory;

    public CachingProxyFactory(IProxyFactory factory) {
        this.factory = factory;
    }

    @Override
    public Class<?> createClass(Class<?> clazz) {
        return getFactory().createClass(clazz);
    }

    @Override
    public Object createInstance(final Class<?> proxyClass, final Callback callback) {
        return getFactory().createInstance(proxyClass, callback);
    }

    @Override
    public Callback getCallback(Object proxy) {
        return getFactory().getCallback(proxy);
    }

    private IProxyFactory getFactory() {
        Object key;
        if (Application.exists()) {
            key = Application.get();
        } else {
            key = CachingProxyFactory.class;
        }

        IProxyFactory result = scopes.get(key);
        if (result == null) {
            IProxyFactory tmpResult = scopes.putIfAbsent(key, result = new ApplicationScope());
            if (tmpResult != null) {
                result = tmpResult;
            }
        }

        return result;
    }

    public void destroy(Application application) {
        scopes.remove(application);
    }

    private class ApplicationScope implements IProxyFactory {

        private final Map<Class<?>, Class<?>> proxyClasses = new ConcurrentHashMap<Class<?>, Class<?>>();

        @Override
        public Class<?> createClass(Class<?> clazz) {
            Class<?> proxyClazz = proxyClasses.get(clazz);
            if (proxyClazz == null) {
                proxyClazz = factory.createClass(clazz);
                if (proxyClazz == null) {
                    proxyClazz = NOT_PROXYABLE.class;
                }
                proxyClasses.put(clazz, proxyClazz);
            }

            if (proxyClazz == NOT_PROXYABLE.class) {
                proxyClazz = null;
            }

            return proxyClazz;
        }

        @Override
        public Object createInstance(final Class<?> proxyClass, final Callback callback) {
            return factory.createInstance(proxyClass, callback);
        }

        @Override
        public Callback getCallback(Object proxy) {
            return factory.getCallback(proxy);
        }
    }

    private class NOT_PROXYABLE {
    }
}