org.jclouds.openstack.nova.v2_0.compute.loaders.FindSecurityGroupOrCreate.java Source code

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Here is the source code for org.jclouds.openstack.nova.v2_0.compute.loaders.FindSecurityGroupOrCreate.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.openstack.nova.v2_0.compute.loaders;

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

import java.util.concurrent.atomic.AtomicReference;

import javax.inject.Inject;
import javax.inject.Named;

import org.jclouds.openstack.nova.v2_0.domain.zonescoped.SecurityGroupInZone;
import org.jclouds.openstack.nova.v2_0.domain.zonescoped.ZoneAndName;
import org.jclouds.openstack.nova.v2_0.domain.zonescoped.ZoneSecurityGroupNameAndPorts;

import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.cache.CacheLoader;
import com.google.common.util.concurrent.Atomics;

/**
 * 
 * @author Adrian Cole
 */
public class FindSecurityGroupOrCreate extends CacheLoader<ZoneAndName, SecurityGroupInZone> {

    protected final Predicate<AtomicReference<ZoneAndName>> returnSecurityGroupExistsInZone;
    protected final Function<ZoneSecurityGroupNameAndPorts, SecurityGroupInZone> groupCreator;

    @Inject
    public FindSecurityGroupOrCreate(
            @Named("SECURITYGROUP_PRESENT") Predicate<AtomicReference<ZoneAndName>> returnSecurityGroupExistsInZone,
            Function<ZoneSecurityGroupNameAndPorts, SecurityGroupInZone> groupCreator) {
        this.returnSecurityGroupExistsInZone = checkNotNull(returnSecurityGroupExistsInZone,
                "returnSecurityGroupExistsInZone");
        this.groupCreator = checkNotNull(groupCreator, "groupCreator");
    }

    @Override
    public SecurityGroupInZone load(ZoneAndName in) {
        AtomicReference<ZoneAndName> securityGroupInZoneRef = Atomics
                .newReference(checkNotNull(in, "zoneSecurityGroupNameAndPorts"));
        if (returnSecurityGroupExistsInZone.apply(securityGroupInZoneRef)) {
            return returnExistingSecurityGroup(securityGroupInZoneRef);
        } else {
            return createNewSecurityGroup(in);
        }
    }

    private SecurityGroupInZone returnExistingSecurityGroup(AtomicReference<ZoneAndName> securityGroupInZoneRef) {
        ZoneAndName securityGroupInZone = securityGroupInZoneRef.get();
        checkState(securityGroupInZone instanceof SecurityGroupInZone,
                "programming error: predicate %s should update the atomic reference to the actual security group found",
                returnSecurityGroupExistsInZone);
        return SecurityGroupInZone.class.cast(securityGroupInZone);
    }

    private SecurityGroupInZone createNewSecurityGroup(ZoneAndName in) {
        checkState(checkNotNull(in, "zoneSecurityGroupNameAndPorts") instanceof ZoneSecurityGroupNameAndPorts,
                "programming error: when issuing get to this cacheloader, you need to pass an instance of ZoneSecurityGroupNameAndPorts, not %s",
                in);
        ZoneSecurityGroupNameAndPorts zoneSecurityGroupNameAndPorts = ZoneSecurityGroupNameAndPorts.class.cast(in);
        return groupCreator.apply(zoneSecurityGroupNameAndPorts);
    }

    @Override
    public String toString() {
        return "returnExistingSecurityGroupInZoneOrCreateAsNeeded()";
    }

}