/*
 * Licensed to Elastic Search and Shay Banon under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Elastic Search 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.elasticsearch.cluster.routing.allocation.decider;

import org.elasticsearch.cluster.routing.MutableShardRouting;
import org.elasticsearch.cluster.routing.RoutingNode;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.allocation.RoutingAllocation;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.Settings;

/**
 * An allocation strategy that does not allow for the same shard instance to be allocated on the same node.
 */
public class SameShardAllocationDecider extends AllocationDecider {

    @Inject public SameShardAllocationDecider(Settings settings) {
        super(settings);
    }

    @Override public Decision canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
        for (MutableShardRouting current : node.shards()) {
            // we do not allow for two shards of the same shard id to exists on the same node
            if (current.shardId().equals(shardRouting.shardId())) {
                return Decision.NO;
            }
        }
        return Decision.YES;
    }
}

/*
 * Licensed to Elastic Search and Shay Banon under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Elastic Search 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.elasticsearch.cluster.routing.allocation.decider;

import org.elasticsearch.cluster.routing.MutableShardRouting;
import org.elasticsearch.cluster.routing.RoutingNode;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.allocation.RoutingAllocation;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.Settings;

import java.util.List;

/**
 * An allocation strategy that does not allow for the same shard instance to be allocated on the same node.
 */
public class SameShardAllocationDecider extends AllocationDecider {

    @Inject public SameShardAllocationDecider(Settings settings) {
        super(settings);
    }

    @Override public Decision canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
        List<MutableShardRouting> shards = node.shards();
        for (int i = 0; i < shards.size(); i++) {
            // we do not allow for two shards of the same shard id to exists on the same node
            if (shards.get(i).shardId().equals(shardRouting.shardId())) {
                return Decision.NO;
            }
        }
        return Decision.YES;
    }
}

use index iteration over iterator