org.apache.samza.execution.StreamManager.java Source code

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Here is the source code for org.apache.samza.execution.StreamManager.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.apache.samza.execution;

import com.google.common.collect.HashMultimap;
import com.google.common.collect.Multimap;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.samza.SamzaException;
import org.apache.samza.system.StreamSpec;
import org.apache.samza.system.SystemAdmin;
import org.apache.samza.system.SystemStreamMetadata;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class StreamManager {
    private static final Logger LOGGER = LoggerFactory.getLogger(StreamManager.class);

    private final Map<String, SystemAdmin> sysAdmins;

    public StreamManager(Map<String, SystemAdmin> sysAdmins) {
        this.sysAdmins = sysAdmins;
    }

    public void createStreams(List<StreamSpec> streams) {
        Multimap<String, StreamSpec> streamsGroupedBySystem = HashMultimap.create();
        streams.forEach(streamSpec -> streamsGroupedBySystem.put(streamSpec.getSystemName(), streamSpec));

        for (Map.Entry<String, Collection<StreamSpec>> entry : streamsGroupedBySystem.asMap().entrySet()) {
            String systemName = entry.getKey();
            SystemAdmin systemAdmin = sysAdmins.get(systemName);

            for (StreamSpec stream : entry.getValue()) {
                LOGGER.info("Creating stream {} with partitions {} on system {}",
                        new Object[] { stream.getPhysicalName(), stream.getPartitionCount(), systemName });
                systemAdmin.createStream(stream);
            }
        }
    }

    Map<String, Integer> getStreamPartitionCounts(String systemName, Set<String> streamNames) {
        Map<String, Integer> streamToPartitionCount = new HashMap<>();

        SystemAdmin systemAdmin = sysAdmins.get(systemName);
        if (systemAdmin == null) {
            throw new SamzaException(String.format("System %s does not exist.", systemName));
        }

        // retrieve the metadata for the streams in this system
        Map<String, SystemStreamMetadata> streamToMetadata = systemAdmin.getSystemStreamMetadata(streamNames);
        // set the partitions of a stream to its StreamEdge
        streamToMetadata.forEach((stream, data) -> streamToPartitionCount.put(stream,
                data.getSystemStreamPartitionMetadata().size()));

        return streamToPartitionCount;
    }
}