com.mellanox.r4h.CorruptFileBlockIterator.java Source code

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Here is the source code for com.mellanox.r4h.CorruptFileBlockIterator.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 com.mellanox.r4h;

import java.io.IOException;
import java.util.NoSuchElementException;

import org.apache.hadoop.hdfs.protocol.CorruptFileBlocks;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.RemoteIterator;

/**
 * Provides an iterator interface for listCorruptFileBlocks.
 * This class is used by DistributedFileSystem and Hdfs.
 */
public class CorruptFileBlockIterator implements RemoteIterator<Path> {
    private final DFSClient dfs;
    private final String path;

    private String[] files = null;
    private int fileIdx = 0;
    private String cookie = null;
    private Path nextPath = null;

    private int callsMade = 0;

    public CorruptFileBlockIterator(DFSClient dfs, Path path) throws IOException {
        this.dfs = dfs;
        this.path = path2String(path);
        loadNext();
    }

    /**
     * @return the number of calls made to the DFSClient.
     *         This is for debugging and testing purposes.
     */
    public int getCallsMade() {
        return callsMade;
    }

    private String path2String(Path path) {
        return path.toUri().getPath();
    }

    private Path string2Path(String string) {
        return new Path(string);
    }

    private void loadNext() throws IOException {
        if (files == null || fileIdx >= files.length) {
            CorruptFileBlocks cfb = dfs.listCorruptFileBlocks(path, cookie);
            files = cfb.getFiles();
            cookie = cfb.getCookie();
            fileIdx = 0;
            callsMade++;
        }

        if (fileIdx >= files.length) {
            // received an empty response
            // there are no more corrupt file blocks
            nextPath = null;
        } else {
            nextPath = string2Path(files[fileIdx]);
            fileIdx++;
        }
    }

    @Override
    public boolean hasNext() {
        return nextPath != null;
    }

    @Override
    public Path next() throws IOException {
        if (!hasNext()) {
            throw new NoSuchElementException("No more corrupt file blocks");
        }

        Path result = nextPath;
        loadNext();

        return result;
    }
}