demo.vmware.commands.poweroftwo.CommandPowerOfTwoHelper.java Source code

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Here is the source code for demo.vmware.commands.poweroftwo.CommandPowerOfTwoHelper.java

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/*
 * Copyright 2011 VMWare.
 *
 * 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 demo.vmware.commands.poweroftwo;

import org.apache.log4j.Logger;
import org.springframework.cache.annotation.Cacheable;

/**
 * Implementaton of the interface. Think of this as an expensive service that we want to cache the results of. It will be coughed up
 * by spring as a proxy if we have the cachable scanner running
 * 
 * @author freemanj
 * 
 */
public class CommandPowerOfTwoHelper implements ICommandPowerOfTwoHelper {

    public static final Logger LOG = Logger.getLogger(CommandPowerOfTwoHelper.class);

    /** invocation count used by command to see if we got a cache hit */
    private int hitCount = 0;

    /*
     * (non-Javadoc)
     * 
     * @see demo.vmware.commands.ICommandPowerOfTWo#calculateNthPower(java.lang.Integer)
     */
    @Override
    @Cacheable("POWERTABLE")
    public Integer calculateNthPower(Integer targetNumber) {
        LOG.info("Not cached so calculating 2^" + targetNumber);
        hitCount++;
        Double result = Math.pow(2.0, targetNumber);
        try {
            // simulate long running service with 3 second delay
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            // don't care
        }

        return new Integer(result.intValue());
    }

    /**
     * returns the invocation count.
     * 
     * @return
     */
    @Override
    public int getHitCount() {
        return hitCount;
    }

}