co.cask.cdap.data.stream.service.InMemoryStreamMetaStore.java Source code

Introduction

Here is the source code for co.cask.cdap.data.stream.service.InMemoryStreamMetaStore.java

Source

/*
 * Copyright  2015 Cask Data, Inc.
 *
 * Licensed 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 co.cask.cdap.data.stream.service;

import co.cask.cdap.api.data.stream.StreamSpecification;
import co.cask.cdap.proto.Id;
import com.google.common.base.Function;
import com.google.common.collect.Collections2;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMultimap;
import com.google.common.collect.Multimap;
import com.google.common.collect.Multimaps;

import java.util.Collection;
import java.util.List;
import javax.annotation.Nullable;

/**
 * In-memory implementation of the {@link StreamMetaStore}. Used for testing.
 */
public class InMemoryStreamMetaStore implements StreamMetaStore {

    private final Multimap<String, String> streams;

    public InMemoryStreamMetaStore() {
        this.streams = Multimaps.synchronizedMultimap(HashMultimap.<String, String>create());
    }

    @Override
    public void addStream(Id.Stream streamId) throws Exception {
        streams.put(streamId.getNamespaceId(), streamId.getId());
    }

    @Override
    public void removeStream(Id.Stream streamId) throws Exception {
        streams.remove(streamId.getNamespaceId(), streamId.getId());
    }

    @Override
    public boolean streamExists(Id.Stream streamId) throws Exception {
        return streams.containsEntry(streamId.getNamespaceId(), streamId.getId());
    }

    @Override
    public List<StreamSpecification> listStreams(Id.Namespace namespaceId) throws Exception {
        ImmutableList.Builder<StreamSpecification> builder = ImmutableList.builder();
        synchronized (streams) {
            for (String stream : streams.get(namespaceId.getId())) {
                builder.add(new StreamSpecification.Builder().setName(stream).create());
            }
        }
        return builder.build();
    }

    @Override
    public synchronized Multimap<Id.Namespace, StreamSpecification> listStreams() throws Exception {
        ImmutableMultimap.Builder<Id.Namespace, StreamSpecification> builder = ImmutableMultimap.builder();
        for (String namespaceId : streams.keySet()) {
            synchronized (streams) {
                Collection<String> streamNames = streams.get(namespaceId);
                builder.putAll(Id.Namespace.from(namespaceId),
                        Collections2.transform(streamNames, new Function<String, StreamSpecification>() {
                            @Nullable
                            @Override
                            public StreamSpecification apply(String input) {
                                return new StreamSpecification.Builder().setName(input).create();
                            }
                        }));
            }
        }
        return builder.build();
    }
}