/*
 * Copyright 2014 Attila Szegedi, Daniel Dekany, Jonathan Revusky
 * 
 * Licensed 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 freemarker.ext.beans;

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

import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import freemarker.ext.util.ModelCache;
import freemarker.ext.util.ModelFactory;
import freemarker.template.TemplateModel;

public class BeansModelCache extends ModelCache {
    private final Map classToFactory = new ConcurrentHashMap();
    private final Set mappedClassNames = new HashSet();

    private final BeansWrapper wrapper;
    
    BeansModelCache(BeansWrapper wrapper) {
        this.wrapper = wrapper;
    }
    
    @Override
    protected boolean isCacheable(Object object) {
        return object.getClass() != Boolean.class; 
    }
    
    @Override
    @SuppressFBWarnings(value="JLM_JSR166_UTILCONCURRENT_MONITORENTER", justification="Locks for factory creation only")
    protected TemplateModel create(Object object) {
        Class clazz = object.getClass();
        
        ModelFactory factory = (ModelFactory) classToFactory.get(clazz);
        
        if (factory == null) {
            // Synchronized so that we won't unnecessarily create the same factory for multiple times in parallel.
            synchronized (classToFactory) {
                factory = (ModelFactory) classToFactory.get(clazz);
                if (factory == null) {
                    String className = clazz.getName();
                    // clear mappings when class reloading is detected
                    if (!mappedClassNames.add(className)) {
                        classToFactory.clear();
                        mappedClassNames.clear();
                        mappedClassNames.add(className);
                    }
                    factory = wrapper.getModelFactory(clazz);
                    classToFactory.put(clazz, factory);
                }
            }
        }
        
        return factory.create(object, wrapper);
    }
}