Java tutorial
/** * 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.bianfeng.bfas.hive.io; import java.io.IOException; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.HashSet; import java.util.IdentityHashMap; import java.util.LinkedList; import java.util.List; import java.util.Map; import java.util.Set; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.fs.BlockLocation; import org.apache.hadoop.fs.FileStatus; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.fs.PathFilter; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.io.compress.CompressionCodec; import org.apache.hadoop.io.compress.CompressionCodecFactory; import org.apache.hadoop.io.compress.SplittableCompressionCodec; import org.apache.hadoop.mapred.FileSplit; import org.apache.hadoop.mapred.InputFormat; import org.apache.hadoop.mapred.InputSplit; import org.apache.hadoop.mapred.InvalidInputException; import org.apache.hadoop.mapred.JobConf; import org.apache.hadoop.mapred.JobConfigurable; import org.apache.hadoop.mapred.LineRecordReader; import org.apache.hadoop.mapred.RecordReader; import org.apache.hadoop.mapred.Reporter; import org.apache.hadoop.mapreduce.security.TokenCache; import org.apache.hadoop.net.NetworkTopology; import org.apache.hadoop.net.Node; import org.apache.hadoop.net.NodeBase; import org.apache.hadoop.util.ReflectionUtils; import org.apache.hadoop.util.StringUtils; /** * A base class for file-based {@link InputFormat}. * * <p><code>FileInputFormat</code> is the base class for all file-based * <code>InputFormat</code>s. This provides a generic implementation of * {@link #getSplits(JobConf, int)}. * Subclasses of <code>FileInputFormat</code> can also override the * {@link #isSplitable(FileSystem, Path)} method to ensure input-files are * not split-up and are processed as a whole by {@link Mapper}s. */ public class RealtimeInputFormat2 implements InputFormat<LongWritable, Text>, JobConfigurable { private CompressionCodecFactory compressionCodecs = null; public void configure(JobConf conf) { compressionCodecs = new CompressionCodecFactory(conf); } protected boolean isSplitable(FileSystem fs, Path file) { final CompressionCodec codec = compressionCodecs.getCodec(file); if (null == codec) { return true; } return codec instanceof SplittableCompressionCodec; } public RecordReader<LongWritable, Text> getRecordReader(InputSplit genericSplit, JobConf job, Reporter reporter) throws IOException { reporter.setStatus(genericSplit.toString()); String delimiter = job.get("textinputformat.record.delimiter"); byte[] recordDelimiterBytes = null; if (null != delimiter) recordDelimiterBytes = delimiter.getBytes(); return new LineRecordReader(job, (FileSplit) genericSplit, recordDelimiterBytes); } public static final Log LOG = LogFactory.getLog(RealtimeInputFormat2.class); private static final double SPLIT_SLOP = 1.1; // 10% slop private long minSplitSize = 1; private static final PathFilter hiddenFileFilter = new PathFilter() { public boolean accept(Path p) { String name = p.getName(); return !name.startsWith("_") && !name.startsWith("."); } }; static final String NUM_INPUT_FILES = "mapreduce.input.num.files"; protected void setMinSplitSize(long minSplitSize) { this.minSplitSize = minSplitSize; } /** * Proxy PathFilter that accepts a path only if all filters given in the * constructor do. Used by the listPaths() to apply the built-in * hiddenFileFilter together with a user provided one (if any). */ private static class MultiPathFilter implements PathFilter { private List<PathFilter> filters; public MultiPathFilter(List<PathFilter> filters) { this.filters = filters; } public boolean accept(Path path) { for (PathFilter filter : filters) { if (!filter.accept(path)) { return false; } } return true; } } /** * Set a PathFilter to be applied to the input paths for the map-reduce job. * * @param filter the PathFilter class use for filtering the input paths. */ public static void setInputPathFilter(JobConf conf, Class<? extends PathFilter> filter) { conf.setClass("mapred.input.pathFilter.class", filter, PathFilter.class); } /** * Get a PathFilter instance of the filter set for the input paths. * * @return the PathFilter instance set for the job, NULL if none has been set. */ public static PathFilter getInputPathFilter(JobConf conf) { Class<? extends PathFilter> filterClass = conf.getClass("mapred.input.pathFilter.class", null, PathFilter.class); return (filterClass != null) ? ReflectionUtils.newInstance(filterClass, conf) : null; } /** List input directories. * Subclasses may override to, e.g., select only files matching a regular * expression. * * @param job the job to list input paths for * @return array of FileStatus objects * @throws IOException if zero items. */ protected FileStatus[] listStatus(JobConf job) throws IOException { Path[] dirs = getInputPaths(job); if (dirs.length == 0) { throw new IOException("No input paths specified in job"); } // get tokens for all the required FileSystems.. TokenCache.obtainTokensForNamenodes(job.getCredentials(), dirs, job); List<FileStatus> result = new ArrayList<FileStatus>(); List<IOException> errors = new ArrayList<IOException>(); // creates a MultiPathFilter with the hiddenFileFilter and the // user provided one (if any). List<PathFilter> filters = new ArrayList<PathFilter>(); filters.add(hiddenFileFilter); PathFilter jobFilter = getInputPathFilter(job); if (jobFilter != null) { filters.add(jobFilter); } PathFilter inputFilter = new MultiPathFilter(filters); for (Path p : dirs) { FileSystem fs = p.getFileSystem(job); FileStatus[] matches = fs.globStatus(p, inputFilter); if (matches == null) { errors.add(new IOException("Input path does not exist: " + p)); } else if (matches.length == 0) { errors.add(new IOException("Input Pattern " + p + " matches 0 files")); } else { for (FileStatus globStat : matches) { if (globStat.isDir()) { for (FileStatus stat : fs.listStatus(globStat.getPath(), inputFilter)) { result.add(stat); } } else { result.add(globStat); } } } } if (!errors.isEmpty()) { throw new InvalidInputException(errors); } LOG.info("Total input paths to process : " + result.size()); return result.toArray(new FileStatus[result.size()]); } /** Splits files returned by {@link #listStatus(JobConf)} when * they're too big.*/ @SuppressWarnings("deprecation") public InputSplit[] getSplits(JobConf job, int numSplits) throws IOException { LOG.warn("test go go go"); FileStatus[] files = listStatus(job); // Save the number of input files in the job-conf job.setLong(NUM_INPUT_FILES, files.length); long totalSize = 0; // compute total size for (FileStatus file : files) { // check we have valid files if (file.isDir()) { throw new IOException("Not a file: " + file.getPath()); } totalSize += file.getLen(); } long goalSize = totalSize / (numSplits == 0 ? 1 : numSplits); long minSize = Math.max(job.getLong("mapred.min.split.size", 1), minSplitSize); // generate splits ArrayList<FileSplit> splits = new ArrayList<FileSplit>(numSplits); NetworkTopology clusterMap = new NetworkTopology(); for (FileStatus file : files) { Path path = file.getPath(); FileSystem fs = path.getFileSystem(job); long length = file.getLen(); BlockLocation[] blkLocations = fs.getFileBlockLocations(file, 0, length); if ((length != 0) && isSplitable(fs, path)) { long blockSize = file.getBlockSize(); long splitSize = computeSplitSize(goalSize, minSize, blockSize); long bytesRemaining = length; while (((double) bytesRemaining) / splitSize > SPLIT_SLOP) { String[] splitHosts = getSplitHosts(blkLocations, length - bytesRemaining, splitSize, clusterMap); splits.add(new FileSplit(path, length - bytesRemaining, splitSize, splitHosts)); bytesRemaining -= splitSize; } if (bytesRemaining != 0) { splits.add(new FileSplit(path, length - bytesRemaining, bytesRemaining, blkLocations[blkLocations.length - 1].getHosts())); } } else if (length != 0) { String[] splitHosts = getSplitHosts(blkLocations, 0, length, clusterMap); splits.add(new FileSplit(path, 0, length, splitHosts)); } else { //Create empty hosts array for zero length files splits.add(new FileSplit(path, 0, length, new String[0])); } } LOG.debug("Total # of splits: " + splits.size()); return splits.toArray(new FileSplit[splits.size()]); } protected long computeSplitSize(long goalSize, long minSize, long blockSize) { return Math.max(minSize, Math.min(goalSize, blockSize)); } protected int getBlockIndex(BlockLocation[] blkLocations, long offset) { for (int i = 0; i < blkLocations.length; i++) { // is the offset inside this block? if ((blkLocations[i].getOffset() <= offset) && (offset < blkLocations[i].getOffset() + blkLocations[i].getLength())) { return i; } } BlockLocation last = blkLocations[blkLocations.length - 1]; long fileLength = last.getOffset() + last.getLength() - 1; throw new IllegalArgumentException("Offset " + offset + " is outside of file (0.." + fileLength + ")"); } /** * Sets the given comma separated paths as the list of inputs * for the map-reduce job. * * @param conf Configuration of the job * @param commaSeparatedPaths Comma separated paths to be set as * the list of inputs for the map-reduce job. */ public static void setInputPaths(JobConf conf, String commaSeparatedPaths) { setInputPaths(conf, StringUtils.stringToPath(getPathStrings(commaSeparatedPaths))); } /** * Add the given comma separated paths to the list of inputs for * the map-reduce job. * * @param conf The configuration of the job * @param commaSeparatedPaths Comma separated paths to be added to * the list of inputs for the map-reduce job. */ public static void addInputPaths(JobConf conf, String commaSeparatedPaths) { for (String str : getPathStrings(commaSeparatedPaths)) { addInputPath(conf, new Path(str)); } } /** * Set the array of {@link Path}s as the list of inputs * for the map-reduce job. * * @param conf Configuration of the job. * @param inputPaths the {@link Path}s of the input directories/files * for the map-reduce job. */ public static void setInputPaths(JobConf conf, Path... inputPaths) { Path path = new Path(conf.getWorkingDirectory(), inputPaths[0]); StringBuffer str = new StringBuffer(StringUtils.escapeString(path.toString())); for (int i = 1; i < inputPaths.length; i++) { str.append(StringUtils.COMMA_STR); path = new Path(conf.getWorkingDirectory(), inputPaths[i]); str.append(StringUtils.escapeString(path.toString())); } conf.set("mapred.input.dir", str.toString()); } /** * Add a {@link Path} to the list of inputs for the map-reduce job. * * @param conf The configuration of the job * @param path {@link Path} to be added to the list of inputs for * the map-reduce job. */ public static void addInputPath(JobConf conf, Path path) { path = new Path(conf.getWorkingDirectory(), path); String dirStr = StringUtils.escapeString(path.toString()); String dirs = conf.get("mapred.input.dir"); conf.set("mapred.input.dir", dirs == null ? dirStr : dirs + StringUtils.COMMA_STR + dirStr); } // This method escapes commas in the glob pattern of the given paths. private static String[] getPathStrings(String commaSeparatedPaths) { int length = commaSeparatedPaths.length(); int curlyOpen = 0; int pathStart = 0; boolean globPattern = false; List<String> pathStrings = new ArrayList<String>(); for (int i = 0; i < length; i++) { char ch = commaSeparatedPaths.charAt(i); switch (ch) { case '{': { curlyOpen++; if (!globPattern) { globPattern = true; } break; } case '}': { curlyOpen--; if (curlyOpen == 0 && globPattern) { globPattern = false; } break; } case ',': { if (!globPattern) { pathStrings.add(commaSeparatedPaths.substring(pathStart, i)); pathStart = i + 1; } break; } } } pathStrings.add(commaSeparatedPaths.substring(pathStart, length)); return pathStrings.toArray(new String[0]); } /** * Get the list of input {@link Path}s for the map-reduce job. * * @param conf The configuration of the job * @return the list of input {@link Path}s for the map-reduce job. */ public static Path[] getInputPaths(JobConf conf) { String dirs = conf.get("mapred.input.dir", ""); String[] list = StringUtils.split(dirs); Path[] result = new Path[list.length]; for (int i = 0; i < list.length; i++) { result[i] = new Path(StringUtils.unEscapeString(list[i])); } return result; } private void sortInDescendingOrder(List<NodeInfo> mylist) { Collections.sort(mylist, new Comparator<NodeInfo>() { public int compare(NodeInfo obj1, NodeInfo obj2) { if (obj1 == null || obj2 == null) return -1; if (obj1.getValue() == obj2.getValue()) { return 0; } else { return ((obj1.getValue() < obj2.getValue()) ? 1 : -1); } } }); } /** * This function identifies and returns the hosts that contribute * most for a given split. For calculating the contribution, rack * locality is treated on par with host locality, so hosts from racks * that contribute the most are preferred over hosts on racks that * contribute less * @param blkLocations The list of block locations * @param offset * @param splitSize * @return array of hosts that contribute most to this split * @throws IOException */ protected String[] getSplitHosts(BlockLocation[] blkLocations, long offset, long splitSize, NetworkTopology clusterMap) throws IOException { int startIndex = getBlockIndex(blkLocations, offset); long bytesInThisBlock = blkLocations[startIndex].getOffset() + blkLocations[startIndex].getLength() - offset; //If this is the only block, just return if (bytesInThisBlock >= splitSize) { return blkLocations[startIndex].getHosts(); } long bytesInFirstBlock = bytesInThisBlock; int index = startIndex + 1; splitSize -= bytesInThisBlock; while (splitSize > 0) { bytesInThisBlock = Math.min(splitSize, blkLocations[index++].getLength()); splitSize -= bytesInThisBlock; } long bytesInLastBlock = bytesInThisBlock; int endIndex = index - 1; Map<Node, NodeInfo> hostsMap = new IdentityHashMap<Node, NodeInfo>(); Map<Node, NodeInfo> racksMap = new IdentityHashMap<Node, NodeInfo>(); String[] allTopos = new String[0]; // Build the hierarchy and aggregate the contribution of // bytes at each level. See TestGetSplitHosts.java for (index = startIndex; index <= endIndex; index++) { // Establish the bytes in this block if (index == startIndex) { bytesInThisBlock = bytesInFirstBlock; } else if (index == endIndex) { bytesInThisBlock = bytesInLastBlock; } else { bytesInThisBlock = blkLocations[index].getLength(); } allTopos = blkLocations[index].getTopologyPaths(); // If no topology information is available, just // prefix a fakeRack if (allTopos.length == 0) { allTopos = fakeRacks(blkLocations, index); } // NOTE: This code currently works only for one level of // hierarchy (rack/host). However, it is relatively easy // to extend this to support aggregation at different // levels for (String topo : allTopos) { Node node, parentNode; NodeInfo nodeInfo, parentNodeInfo; node = clusterMap.getNode(topo); if (node == null) { node = new NodeBase(topo); clusterMap.add(node); } nodeInfo = hostsMap.get(node); if (nodeInfo == null) { nodeInfo = new NodeInfo(node); hostsMap.put(node, nodeInfo); parentNode = node.getParent(); parentNodeInfo = racksMap.get(parentNode); if (parentNodeInfo == null) { parentNodeInfo = new NodeInfo(parentNode); racksMap.put(parentNode, parentNodeInfo); } parentNodeInfo.addLeaf(nodeInfo); } else { nodeInfo = hostsMap.get(node); parentNode = node.getParent(); parentNodeInfo = racksMap.get(parentNode); } nodeInfo.addValue(index, bytesInThisBlock); parentNodeInfo.addValue(index, bytesInThisBlock); } // for all topos } // for all indices return identifyHosts(allTopos.length, racksMap); } private String[] identifyHosts(int replicationFactor, Map<Node, NodeInfo> racksMap) { String[] retVal = new String[replicationFactor]; List<NodeInfo> rackList = new LinkedList<NodeInfo>(); rackList.addAll(racksMap.values()); // Sort the racks based on their contribution to this split sortInDescendingOrder(rackList); boolean done = false; int index = 0; // Get the host list for all our aggregated items, sort // them and return the top entries for (NodeInfo ni : rackList) { Set<NodeInfo> hostSet = ni.getLeaves(); List<NodeInfo> hostList = new LinkedList<NodeInfo>(); hostList.addAll(hostSet); // Sort the hosts in this rack based on their contribution sortInDescendingOrder(hostList); for (NodeInfo host : hostList) { // Strip out the port number from the host name retVal[index++] = host.node.getName().split(":")[0]; if (index == replicationFactor) { done = true; break; } } if (done == true) { break; } } return retVal; } private String[] fakeRacks(BlockLocation[] blkLocations, int index) throws IOException { String[] allHosts = blkLocations[index].getHosts(); String[] allTopos = new String[allHosts.length]; for (int i = 0; i < allHosts.length; i++) { allTopos[i] = NetworkTopology.DEFAULT_RACK + "/" + allHosts[i]; } return allTopos; } private static class NodeInfo { final Node node; final Set<Integer> blockIds; final Set<NodeInfo> leaves; private long value; NodeInfo(Node node) { this.node = node; blockIds = new HashSet<Integer>(); leaves = new HashSet<NodeInfo>(); } long getValue() { return value; } void addValue(int blockIndex, long value) { if (blockIds.add(blockIndex) == true) { this.value += value; } } Set<NodeInfo> getLeaves() { return leaves; } void addLeaf(NodeInfo nodeInfo) { leaves.add(nodeInfo); } } }