org.jclouds.ec2.compute.predicates.InstancePresent.java Source code

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Here is the source code for org.jclouds.ec2.compute.predicates.InstancePresent.java

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/**
 *
 * Copyright (C) 2010 Cloud Conscious, LLC. <info@cloudconscious.com>
 *
 * ====================================================================
 * 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.jclouds.ec2.compute.predicates;

import static com.google.common.base.Preconditions.checkNotNull;

import java.util.NoSuchElementException;

import javax.annotation.Resource;
import javax.inject.Singleton;

import org.jclouds.ec2.EC2Client;
import org.jclouds.ec2.compute.domain.RegionAndName;
import org.jclouds.logging.Logger;
import org.jclouds.rest.ResourceNotFoundException;

import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;
import com.google.inject.Inject;

/**
 * 
 * @author Adrian Cole
 */
@Singleton
public class InstancePresent implements Predicate<RegionAndName> {

    private final EC2Client client;

    @Resource
    protected Logger logger = Logger.NULL;

    @Inject
    public InstancePresent(EC2Client client) {
        this.client = checkNotNull(client, "client");
    }

    public boolean apply(RegionAndName instance) {
        logger.trace("looking for instance %s/%s", instance.getRegion(), instance.getName());
        try {
            refresh(instance);
            return true;
        } catch (ResourceNotFoundException e) {
            return false;
        } catch (NoSuchElementException e) {
            return false;
        }
    }

    protected void refresh(RegionAndName instance) {
        Iterables.getOnlyElement(Iterables.getOnlyElement(
                client.getInstanceServices().describeInstancesInRegion(instance.getRegion(), instance.getName())));
    }
}