/** * Copyright 2013 ARRIS, 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 parquet.tools.command; import java.io.PrintWriter; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.Option; import org.apache.commons.cli.OptionBuilder; import org.apache.commons.cli.Options; import org.apache.hadoop.fs.Path; import parquet.hadoop.ParquetReader; import parquet.tools.Main; import parquet.tools.read.SimpleReadSupport; import parquet.tools.read.SimpleRecord; public class HeadCommand extends ArgsOnlyCommand { private static final long DEFAULT = 5; public static final String[] USAGE = new String[] { "<input>", "where <input> is the parquet file to print to stdout" }; public static final Options OPTIONS; static { OPTIONS = new Options(); Option help = OptionBuilder.withLongOpt("records") .withDescription("The number of records to show (default: " + DEFAULT + ")") .hasOptionalArg() .create('n'); OPTIONS.addOption(help); } public HeadCommand() { super(1, 1); } @Override public Options getOptions() { return OPTIONS; } @Override public String[] getUsageDescription() { return USAGE; } @Override public void execute(CommandLine options) throws Exception { super.execute(options); long num = DEFAULT; if (options.hasOption('n')) { num = Long.parseLong(options.getOptionValue('n')); } String[] args = options.getArgs(); String input = args[0]; ParquetReader<SimpleRecord> reader = null; try { PrintWriter writer = new PrintWriter(Main.out, true); reader = new ParquetReader<SimpleRecord>(new Path(input), new SimpleReadSupport()); for (SimpleRecord value = reader.read(); value != null && num-- > 0; value = reader.read()) { value.prettyPrint(writer); writer.println(); } } finally { if (reader != null) { try { reader.close(); } catch (Exception ex) { } } } } }