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 hivemall; import hivemall.utils.lang.CommandLineUtils; import java.io.PrintWriter; import java.io.StringWriter; import javax.annotation.Nonnull; import javax.annotation.Nullable; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.Options; import org.apache.hadoop.hive.ql.exec.Description; import org.apache.hadoop.hive.ql.exec.MapredContext; import org.apache.hadoop.hive.ql.exec.UDFArgumentException; import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator; import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector; import org.apache.hadoop.mapred.Counters.Counter; import org.apache.hadoop.mapred.Reporter; public abstract class UDAFEvaluatorWithOptions extends GenericUDAFEvaluator { @Nullable protected MapredContext mapredContext; @Override public final void configure(MapredContext mapredContext) { this.mapredContext = mapredContext; } @Nullable protected final Reporter getReporter() { if (mapredContext == null) { return null; } return mapredContext.getReporter(); } protected static void reportProgress(@Nullable Reporter reporter) { if (reporter != null) { synchronized (reporter) { reporter.progress(); } } } protected static void setCounterValue(@Nullable Counter counter, long value) { if (counter != null) { synchronized (counter) { counter.setValue(value); } } } protected static void incrCounter(@Nullable Counter counter, long incr) { if (counter != null) { synchronized (counter) { counter.increment(incr); } } } @Nonnull protected abstract Options getOptions(); @Nonnull protected final CommandLine parseOptions(@Nonnull String optionValue) throws UDFArgumentException { String[] args = optionValue.split("\\s+"); Options opts = getOptions(); opts.addOption("help", false, "Show function help"); CommandLine cl = CommandLineUtils.parseOptions(args, opts); if (cl.hasOption("help")) { Description funcDesc = getClass().getAnnotation(Description.class); final String cmdLineSyntax; if (funcDesc == null) { cmdLineSyntax = getClass().getSimpleName(); } else { String funcName = funcDesc.name(); cmdLineSyntax = funcName == null ? getClass().getSimpleName() : funcDesc.value().replace("_FUNC_", funcDesc.name()); } StringWriter sw = new StringWriter(); sw.write('\n'); PrintWriter pw = new PrintWriter(sw); HelpFormatter formatter = new HelpFormatter(); formatter.printHelp(pw, HelpFormatter.DEFAULT_WIDTH, cmdLineSyntax, null, opts, HelpFormatter.DEFAULT_LEFT_PAD, HelpFormatter.DEFAULT_DESC_PAD, null, true); pw.flush(); String helpMsg = sw.toString(); throw new UDFArgumentException(helpMsg); } return cl; } protected abstract CommandLine processOptions(ObjectInspector[] argOIs) throws UDFArgumentException; }