com.cloudera.hadoop.hdfs.nfs.nfs4.WritableFileFileHandleStore.java Source code

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Here is the source code for com.cloudera.hadoop.hdfs.nfs.nfs4.WritableFileFileHandleStore.java

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/**
 * Copyright 2011 The Apache Software Foundation
 *
 * 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 com.cloudera.hadoop.hdfs.nfs.nfs4;

import static com.cloudera.hadoop.hdfs.nfs.nfs4.Constants.*;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;
import java.util.Collections;
import java.util.List;

import org.apache.hadoop.conf.Configuration;

import com.cloudera.hadoop.hdfs.nfs.Pair;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import org.apache.log4j.Logger;

public class WritableFileFileHandleStore extends FileHandleStore {
    protected static final Logger LOGGER = Logger.getLogger(WritableFileFileHandleStore.class);

    File mFileHandleStoreFile;

    protected DataOutputStream mFileHandleStore;
    protected FileChannel mFileHandleStoreChannel;

    @Override
    protected synchronized void initialize() throws IOException {

        Configuration configuration = getConf();

        mFileHandleStoreFile = new File(
                configuration.get(NFS_FILEHANDLE_STORE_FILE, DEFAULT_NFS_FILEHANDLE_STORE_FILE));

        Pair<List<FileHandleStoreEntry>, Boolean> pair = readFile();
        boolean fileHandleStoreIsBad = pair.getSecond();

        try {
            mFileHandleStoreFile.delete();
            FileOutputStream fos = new FileOutputStream(mFileHandleStoreFile);
            mFileHandleStoreChannel = fos.getChannel();
            mFileHandleStore = new DataOutputStream(fos);
            List<FileHandleStoreEntry> entryList = pair.getFirst();
            Collections.sort(entryList);
            for (FileHandleStoreEntry entry : entryList) {
                storeFileHandle(entry);
            }
            if (fileHandleStoreIsBad) {
                LOGGER.info("FileHandleStore fixed");
            }
        } catch (IOException ex) {
            throw new IOException("Unable to create filehandle store file: " + mFileHandleStoreFile, ex);
        }

    }

    protected Pair<List<FileHandleStoreEntry>, Boolean> readFile() throws IOException {
        List<FileHandleStoreEntry> entryList = Lists.newArrayList();
        boolean fileHandleStoreIsBad = false;
        if (mFileHandleStoreFile.isFile()) {
            LOGGER.info("Reading FileHandleStore " + mFileHandleStoreFile);
            try {
                FileInputStream fis = new FileInputStream(mFileHandleStoreFile);
                DataInputStream is = new DataInputStream(fis);
                try {
                    boolean moreEntries = false;
                    try {
                        moreEntries = is.readBoolean();
                    } catch (EOFException e) {
                        LOGGER.warn("FileHandleStore was not finished (process probably died/killed)");
                        fileHandleStoreIsBad = true;
                        moreEntries = false;
                    }
                    while (moreEntries) {
                        FileHandleStoreEntry entry = new FileHandleStoreEntry();
                        entry.readFields(is);
                        entryList.add(entry);
                        LOGGER.info("Read filehandle " + entry.path + " " + entry.fileID);
                        try {
                            moreEntries = is.readBoolean();
                        } catch (EOFException e) {
                            LOGGER.warn("FileHandleStore was not finished (process probably died/killed)");
                            fileHandleStoreIsBad = true;
                            moreEntries = false;
                        }
                    }
                } finally {
                    is.close();
                }
            } catch (IOException ex) {
                throw new IOException("Unable to read filehandle store file: " + mFileHandleStoreFile, ex);
            }
        }
        return Pair.of(entryList, fileHandleStoreIsBad);
    }

    @Override
    public synchronized ImmutableList<FileHandleStoreEntry> getAll() {
        try {
            return ImmutableList.copyOf(readFile().getFirst());
        } catch (IOException e) {
            LOGGER.warn("Exception reading filehandle store file: " + mFileHandleStoreFile, e);
        }
        return ImmutableList.<FileHandleStoreEntry>of();
    }

    @Override
    public synchronized void storeFileHandle(FileHandleStoreEntry entry) throws IOException {
        mFileHandleStore.writeBoolean(true);
        entry.write(mFileHandleStore);
        mFileHandleStore.flush();
        mFileHandleStoreChannel.force(true);
        LOGGER.info("Wrote filehandle " + entry.path + "  " + entry.fileID);
    }

    @Override
    public synchronized void close() throws IOException {
        mFileHandleStore.writeBoolean(false);
        mFileHandleStore.flush();
        mFileHandleStoreChannel.force(true);
        mFileHandleStore.close();
        mFileHandleStoreChannel.close();
    }
}