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/**
 * Copyright (c) 2013-2016, Neuro4j
 *
 * 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 org.neuro4j.workflow.guice;


import org.neuro4j.workflow.ActionBlock;
import org.neuro4j.workflow.common.FlowExecutionException;
import org.neuro4j.workflow.loader.CustomBlockInitStrategy;
import org.neuro4j.workflow.node.CustomBlock;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.Module;



/**
 * This class allows to use Google Guice library during initialization of all custom blocks.
 *
 */
public class GuiceCustomBlockInitStrategy implements CustomBlockInitStrategy {

	private static final Logger Logger = LoggerFactory.getLogger(GuiceCustomBlockInitStrategy.class);

    /**
     *  Guice's injector.
     */
    private final Injector injector;
    
    /**
     * The constructor.
     * @param modules Guice's modules which will be used by injector.
     */
    public GuiceCustomBlockInitStrategy(Iterable modules) {
        this(Guice.createInjector(modules));
    }
    
    public GuiceCustomBlockInitStrategy(final Injector injector) {
        super();
        this.injector = injector;
    }
    
    @SuppressWarnings("unchecked")
    public ActionBlock loadCustomBlock(String className) throws FlowExecutionException {
        try {

            Class clazz = (Class) Class.forName(className);
            if (null != clazz)
            {
            	ActionBlock customBlock =  injector.getInstance(clazz);
                return customBlock;
            }

        } catch (ClassNotFoundException e) {
            Logger.error(e.getMessage(), e);
            throw new FlowExecutionException(e);
        }
        throw new FlowExecutionException("CustomBlock: " + className + " not found");
    }

}