AbstractHdfsBlobContainer.java

/*
 * Licensed to ElasticSearch and Shay Banon under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. ElasticSearch 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.common.blobstore.hdfs;

import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.PathFilter;
import org.elasticsearch.common.blobstore.BlobMetaData;
import org.elasticsearch.common.blobstore.BlobPath;
import org.elasticsearch.common.blobstore.support.AbstractBlobContainer;
import org.elasticsearch.common.blobstore.support.PlainBlobMetaData;
import org.elasticsearch.common.collect.ImmutableMap;

import java.io.IOException;

/**
 *
 */
public abstract class AbstractHdfsBlobContainer extends AbstractBlobContainer {

    protected final HdfsBlobStore blobStore;

    protected final Path path;

    public AbstractHdfsBlobContainer(HdfsBlobStore blobStore, BlobPath blobPath, Path path) {
        super(blobPath);
        this.blobStore = blobStore;
        this.path = path;
    }

    public ImmutableMap<String, BlobMetaData> listBlobs() throws IOException {
        FileStatus[] files = blobStore.fileSystem().listStatus(path);
        if (files == null || files.length == 0) {
            return ImmutableMap.of();
        }
        ImmutableMap.Builder<String, BlobMetaData> builder = ImmutableMap.builder();
        for (FileStatus file : files) {
            builder.put(file.getPath().getName(), new PlainBlobMetaData(file.getPath().getName(), file.getLen()));
        }
        return builder.build();
    }

    @Override
    public ImmutableMap<String, BlobMetaData> listBlobsByPrefix(final String blobNamePrefix) throws IOException {
        FileStatus[] files = blobStore.fileSystem().listStatus(path, new PathFilter() {
            @Override
            public boolean accept(Path path) {
                return path.getName().startsWith(blobNamePrefix);
            }
        });
        if (files == null || files.length == 0) {
            return ImmutableMap.of();
        }
        ImmutableMap.Builder<String, BlobMetaData> builder = ImmutableMap.builder();
        for (FileStatus file : files) {
            builder.put(file.getPath().getName(), new PlainBlobMetaData(file.getPath().getName(), file.getLen()));
        }
        return builder.build();
    }

    public boolean deleteBlob(String blobName) throws IOException {
        return blobStore.fileSystem().delete(new Path(path, blobName), true);
    }

    @Override
    public boolean blobExists(String blobName) {
        try {
            return blobStore.fileSystem().exists(new Path(path, blobName));
        } catch (IOException e) {
            return false;
        }
    }

    @Override
    public void readBlob(final String blobName, final ReadBlobListener listener) {
        blobStore.executor().execute(new Runnable() {
            @Override
            public void run() {
                byte[] buffer = new byte[blobStore.bufferSizeInBytes()];


                FSDataInputStream fileStream;
                try {
                    fileStream = blobStore.fileSystem().open(new Path(path, blobName));
                } catch (IOException e) {
                    listener.onFailure(e);
                    return;
                }
                try {
                    int bytesRead;
                    while ((bytesRead = fileStream.read(buffer)) != -1) {
                        listener.onPartial(buffer, 0, bytesRead);
                    }
                    listener.onCompleted();
                } catch (Exception e) {
                    try {
                        fileStream.close();
                    } catch (IOException e1) {
                        // ignore
                    }
                    listener.onFailure(e);
                }
            }
        });
    }
}