org.apache.helix.util.RebalanceUtil.java Source code

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package org.apache.helix.util;

/*
 * 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.
 */

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

import org.apache.helix.HelixException;
import org.apache.helix.api.id.PartitionId;
import org.apache.helix.model.IdealState;
import org.apache.helix.model.StateModelDefinition;

import com.google.common.base.Functions;
import com.google.common.collect.Lists;

public class RebalanceUtil {
    public static Map<String, Object> buildInternalIdealState(IdealState state) {
        // Try parse the partition number from name DB_n. If not, sort the partitions and
        // assign id
        Map<String, Integer> partitionIndex = new HashMap<String, Integer>();
        Map<String, String> reversePartitionIndex = new HashMap<String, String>();
        boolean indexInPartitionName = true;
        for (PartitionId partitionId : state.getPartitionIdSet()) {
            String partitionName = partitionId.stringify();
            int lastPos = partitionName.lastIndexOf("_");
            if (lastPos < 0) {
                indexInPartitionName = false;
                break;
            }
            try {
                String idStr = partitionName.substring(lastPos + 1);
                int partition = Integer.parseInt(idStr);
                partitionIndex.put(partitionName, partition);
                reversePartitionIndex.put(state.getResourceId().stringify() + "_" + partition, partitionName);
            } catch (Exception e) {
                indexInPartitionName = false;
                partitionIndex.clear();
                reversePartitionIndex.clear();
                break;
            }
        }

        if (indexInPartitionName == false) {
            List<String> partitions = new ArrayList<String>();
            partitions.addAll(
                    Lists.transform(Lists.newArrayList(state.getPartitionIdSet()), Functions.toStringFunction()));
            Collections.sort(partitions);
            for (int i = 0; i < partitions.size(); i++) {
                partitionIndex.put(partitions.get(i), i);
                reversePartitionIndex.put(state.getResourceId().stringify() + "_" + i, partitions.get(i));
            }
        }

        Map<String, List<Integer>> nodeMasterAssignmentMap = new TreeMap<String, List<Integer>>();
        Map<String, Map<String, List<Integer>>> combinedNodeSlaveAssignmentMap = new TreeMap<String, Map<String, List<Integer>>>();
        for (PartitionId partition : state.getPartitionIdSet()) {
            List<String> instances = state.getRecord().getListField(partition.stringify());
            String master = instances.get(0);
            if (!nodeMasterAssignmentMap.containsKey(master)) {
                nodeMasterAssignmentMap.put(master, new ArrayList<Integer>());
            }
            if (!combinedNodeSlaveAssignmentMap.containsKey(master)) {
                combinedNodeSlaveAssignmentMap.put(master, new TreeMap<String, List<Integer>>());
            }
            nodeMasterAssignmentMap.get(master).add(partitionIndex.get(partition));
            for (int i = 1; i < instances.size(); i++) {
                String instance = instances.get(i);
                Map<String, List<Integer>> slaveMap = combinedNodeSlaveAssignmentMap.get(master);
                if (!slaveMap.containsKey(instance)) {
                    slaveMap.put(instance, new ArrayList<Integer>());
                }
                slaveMap.get(instance).add(partitionIndex.get(partition));
            }
        }

        Map<String, Object> result = new TreeMap<String, Object>();
        result.put("PrimaryAssignmentMap", nodeMasterAssignmentMap);
        result.put("SecondaryAssignmentMap", combinedNodeSlaveAssignmentMap);
        result.put("replicas", Integer.parseInt(state.getReplicas()));
        result.put("partitions", new Integer(state.getRecord().getListFields().size()));
        result.put("reversePartitionIndex", reversePartitionIndex);
        return result;
    }

    public static String[] parseStates(String clusterName, StateModelDefinition stateModDef) {
        String[] result = new String[2];
        String masterStateValue = null, slaveStateValue = null;

        // StateModelDefinition def = new StateModelDefinition(stateModDef);

        List<String> statePriorityList = stateModDef.getStatesPriorityList();

        for (String state : statePriorityList) {
            String count = stateModDef.getNumInstancesPerState(state);
            if (count.equals("1")) {
                if (masterStateValue != null) {
                    throw new HelixException("Invalid or unsupported state model definition");
                }
                masterStateValue = state;
            } else if (count.equalsIgnoreCase("R")) {
                if (slaveStateValue != null) {
                    throw new HelixException("Invalid or unsupported state model definition");
                }
                slaveStateValue = state;
            } else if (count.equalsIgnoreCase("N")) {
                if (!(masterStateValue == null && slaveStateValue == null)) {
                    throw new HelixException("Invalid or unsupported state model definition");
                }
                masterStateValue = slaveStateValue = state;
            }
        }
        if (masterStateValue == null && slaveStateValue == null) {
            throw new HelixException("Invalid or unsupported state model definition");
        }

        if (masterStateValue == null) {
            masterStateValue = slaveStateValue;
        }
        result[0] = masterStateValue;
        result[1] = slaveStateValue;
        return result;
    }
}