org.jclouds.location.suppliers.derived.ZoneIdsFromRegionIdToZoneIdsValues.java Source code

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Here is the source code for org.jclouds.location.suppliers.derived.ZoneIdsFromRegionIdToZoneIdsValues.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.location.suppliers.derived;

import java.util.Collection;
import java.util.Map;
import java.util.Set;

import javax.inject.Inject;
import javax.inject.Singleton;

import org.jclouds.location.Zone;
import org.jclouds.location.suppliers.ZoneIdsSupplier;

import com.google.common.base.Supplier;
import com.google.common.base.Suppliers;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;

/**
 * as opposed to via properties, lets look up zones via api, as they are more likely to change
 */
@Singleton
public class ZoneIdsFromRegionIdToZoneIdsValues implements ZoneIdsSupplier {

    private final Supplier<Map<String, Supplier<Set<String>>>> regionIdToZoneIdsSupplier;

    @Inject
    protected ZoneIdsFromRegionIdToZoneIdsValues(
            @Zone Supplier<Map<String, Supplier<Set<String>>>> regionIdToZoneIdsSupplier) {
        this.regionIdToZoneIdsSupplier = regionIdToZoneIdsSupplier;
    }

    @Override
    public Set<String> get() {
        Collection<Supplier<Set<String>>> zones = regionIdToZoneIdsSupplier.get().values();
        return ImmutableSet
                .copyOf(Iterables.concat(Iterables.transform(zones, Suppliers.<Set<String>>supplierFunction())));
    }

}