uk.co.jwlawson.jcluster.pool.multiway.QuiverMatrixResourceLoader.java Source code

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Here is the source code for uk.co.jwlawson.jcluster.pool.multiway.QuiverMatrixResourceLoader.java

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/**
 * Copyright 2014 John Lawson
 * 
 * QuiverMatrixResourceLoader.java is part of JCluster. 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 uk.co.jwlawson.jcluster.pool.multiway;

import java.lang.reflect.Constructor;

import uk.co.jwlawson.jcluster.data.QuiverKey;
import uk.co.jwlawson.jcluster.data.QuiverMatrix;

import com.github.benmanes.multiway.ResourceLoader;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;

/**
 * @author John Lawson
 * 
 */
public class QuiverMatrixResourceLoader<T extends QuiverMatrix> implements ResourceLoader<QuiverKey<T>, T> {

    private final LoadingCache<QuiverKey<T>, Constructor<T>> constructorCache;

    public QuiverMatrixResourceLoader() {
        constructorCache = getConstructorCache();
    }

    private LoadingCache<QuiverKey<T>, Constructor<T>> getConstructorCache() {
        return CacheBuilder.newBuilder().maximumSize(10).build(new CacheLoader<QuiverKey<T>, Constructor<T>>() {

            @Override
            public Constructor<T> load(QuiverKey<T> key) throws Exception {
                Class<T> clazz = key.getClassObject();
                Constructor<T> constructor;
                try {
                    constructor = clazz.getConstructor(Integer.TYPE, Integer.TYPE);
                } catch (NoSuchMethodException e) {
                    throw new RuntimeException("No constructor found for class " + clazz, e);
                } catch (SecurityException e) {
                    throw new RuntimeException("Cannot access constructor for class " + clazz, e);
                }
                return constructor;
            }
        });
    }

    @Override
    public T load(QuiverKey<T> key) throws Exception {
        Constructor<T> cons = constructorCache.get(key);
        return cons.newInstance(key.getRows(), key.getCols());
    }

}