flink-examples/flink-java-examples/src/main/java/org/apache/flink/examples/java/relational/EmptyFieldsCountAccumulator.java - flink - Git at Google

 /*
  * 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 org.apache.flink.examples.java.relational;

 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;

 import org.apache.commons.lang.StringUtils;
 import org.apache.flink.api.common.JobExecutionResult;
 import org.apache.flink.api.common.accumulators.Accumulator;
 import org.apache.flink.api.java.DataSet;
 import org.apache.flink.api.java.ExecutionEnvironment;
 import org.apache.flink.api.common.functions.RichFilterFunction;
 import org.apache.flink.api.java.tuple.Tuple;
 import org.apache.flink.api.java.tuple.Tuple3;
 import org.apache.flink.configuration.Configuration;

 /**
  * This program filters lines from a CSV file with empty fields. In doing so, it counts the number of empty fields per
  * column within a CSV file using a custom accumulator for vectors. In this context, empty fields are those, that at
  * most contain whitespace characters like space and tab.
  * <p>
  * The input file is a plain text CSV file with the semicolon as field separator and double quotes as field delimiters
  * and three columns. See {@link #getDataSet(ExecutionEnvironment)} for configuration.
  * <p>
  * Usage: <code>FilterAndCountIncompleteLines [&lt;input file path&gt; [&lt;result path&gt;]]</code> <br>
  * <p>
  * This example shows how to use:
  * <ul>
  * <li>custom accumulators
  * <li>tuple data types
  * <li>inline-defined functions
  * </ul>
  */
 @SuppressWarnings("serial")
 public class EmptyFieldsCountAccumulator {

 	// *************************************************************************
 	// PROGRAM
 	// *************************************************************************

 	private static final String EMPTY_FIELD_ACCUMULATOR = "empty-fields";

 	public static void main(final String[] args) throws Exception {

 		if (!parseParameters(args)) {
 			return;
 		}

 		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

 		// get the data set
 		final DataSet<Tuple> file = getDataSet(env);

 		// filter lines with empty fields
 		final DataSet<Tuple> filteredLines = file.filter(new EmptyFieldFilter());

 		// Here, we could do further processing with the filtered lines...
 		JobExecutionResult result;
 		// output the filtered lines
 		if (outputPath == null) {
 			filteredLines.print();
 			result = env.getLastJobExecutionResult();
 		} else {
 			filteredLines.writeAsCsv(outputPath);
 			// execute program
 			result = env.execute("Accumulator example");
 		}

 		// get the accumulator result via its registration key
 		final List<Integer> emptyFields = result.getAccumulatorResult(EMPTY_FIELD_ACCUMULATOR);
 		System.out.format("Number of detected empty fields per column: %s\n", emptyFields);
 	}

 	// *************************************************************************
 	// UTIL METHODS
 	// *************************************************************************

 	private static String filePath;
 	private static String outputPath;

 	private static boolean parseParameters(final String[] programArguments) {

 		if (programArguments.length >= 3) {
 			System.err.println("Usage: FilterAndCountIncompleteLines [<input file path> [<result path>]]");
 			return false;
 		}

 		if (programArguments.length >= 1) {
 			filePath = programArguments[0];
 			if (programArguments.length == 2) {
 				outputPath = programArguments[1];
 			}
 		}

 		return true;
 	}

 	@SuppressWarnings("unchecked")
 	private static DataSet<Tuple> getDataSet(final ExecutionEnvironment env) {

 		DataSet<? extends Tuple> source;
 		if (filePath == null) {
 			source = env.fromCollection(getExampleInputTuples());

 		} else {
 			source = env
 					.readCsvFile(filePath)
 					.fieldDelimiter(";")
 					.types(String.class, String.class, String.class);

 		}

 		return (DataSet<Tuple>) source;
 	}

 	private static Collection<Tuple3<String, String, String>> getExampleInputTuples() {
 		Collection<Tuple3<String, String, String>> inputTuples = new ArrayList<Tuple3<String, String, String>>();
 		inputTuples.add(new Tuple3<String, String, String>("John", "Doe", "Foo Str."));
 		inputTuples.add(new Tuple3<String, String, String>("Joe", "Johnson", ""));
 		inputTuples.add(new Tuple3<String, String, String>(null, "Kate Morn", "Bar Blvd."));
 		inputTuples.add(new Tuple3<String, String, String>("Tim", "Rinny", ""));
 		inputTuples.add(new Tuple3<String, String, String>("Alicia", "Jackson", "  "));
 		return inputTuples;
 	}

 	/**
 	 * This function filters all incoming tuples that have one or more empty fields.
 	 * In doing so, it also counts the number of empty fields per attribute with an accumulator (registered under
 	 * {@link EmptyFieldsCountAccumulator#EMPTY_FIELD_ACCUMULATOR}).
 	 */
 	public static final class EmptyFieldFilter extends RichFilterFunction<Tuple> {

 		// create a new accumulator in each filter function instance
 		// accumulators can be merged later on
 		private final VectorAccumulator emptyFieldCounter = new VectorAccumulator();

 		@Override
 		public void open(final Configuration parameters) throws Exception {
 			super.open(parameters);

 			// register the accumulator instance
 			getRuntimeContext().addAccumulator(EMPTY_FIELD_ACCUMULATOR,
 					this.emptyFieldCounter);
 		}

 		@Override
 		public boolean filter(final Tuple t) {
 			boolean containsEmptyFields = false;

 			// iterate over the tuple fields looking for empty ones
 			for (int pos = 0; pos < t.getArity(); pos++) {

 				final String field = t.getField(pos);
 				if (field == null || field.trim().isEmpty()) {
 					containsEmptyFields = true;

 					// if an empty field is encountered, update the
 					// accumulator
 					this.emptyFieldCounter.add(pos);
 				}
 			}

 			return !containsEmptyFields;
 		}
 	}

 	/**
 	 * This accumulator lets you increase vector components distributedly. The {@link #add(Integer)} method lets you
 	 * increase the <i>n</i>-th vector component by 1, whereat <i>n</i> is the methods parameter. The size of the vector
 	 * is automatically managed.
 	 */
 	public static class VectorAccumulator implements Accumulator<Integer, ArrayList<Integer>> {

 		/** Stores the accumulated vector components. */
 		private final ArrayList<Integer> resultVector;

 		public VectorAccumulator(){
 			this(new ArrayList<Integer>());
 		}

 		public VectorAccumulator(ArrayList<Integer> resultVector){
 			this.resultVector = resultVector;
 		}

 		/**
 		 * Increases the result vector component at the specified position by 1.
 		 */
 		@Override
 		public void add(Integer position) {
 			updateResultVector(position, 1);
 		}

 		/**
 		 * Increases the result vector component at the specified position by the specified delta.
 		 */
 		private void updateResultVector(int position, int delta) {
 			// inflate the vector to contain the given position
 			while (this.resultVector.size() <= position) {
 				this.resultVector.add(0);
 			}

 			// increment the component value
 			final int component = this.resultVector.get(position);
 			this.resultVector.set(position, component + delta);
 		}

 		@Override
 		public ArrayList<Integer> getLocalValue() {
 			return this.resultVector;
 		}

 		@Override
 		public void resetLocal() {
 			// clear the result vector if the accumulator instance shall be reused
 			this.resultVector.clear();
 		}

 		@Override
 		public void merge(final Accumulator<Integer, ArrayList<Integer>> other) {
 			// merge two vector accumulators by adding their up their vector components
 			final List<Integer> otherVector = other.getLocalValue();
 			for (int index = 0; index < otherVector.size(); index++) {
 				updateResultVector(index, otherVector.get(index));
 			}
 		}

 		@Override
 		public Accumulator<Integer, ArrayList<Integer>> clone() {
 			return new VectorAccumulator(new ArrayList<Integer>(resultVector));
 		}

 		@Override
 		public String toString() {
 			return StringUtils.join(resultVector, ',');
 		}
 	}
 }
	/*
	* 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 org.apache.flink.examples.java.relational;

	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.List;

	import org.apache.commons.lang.StringUtils;
	import org.apache.flink.api.common.JobExecutionResult;
	import org.apache.flink.api.common.accumulators.Accumulator;
	import org.apache.flink.api.java.DataSet;
	import org.apache.flink.api.java.ExecutionEnvironment;
	import org.apache.flink.api.common.functions.RichFilterFunction;
	import org.apache.flink.api.java.tuple.Tuple;
	import org.apache.flink.api.java.tuple.Tuple3;
	import org.apache.flink.configuration.Configuration;

	/**
	* This program filters lines from a CSV file with empty fields. In doing so, it counts the number of empty fields per
	* column within a CSV file using a custom accumulator for vectors. In this context, empty fields are those, that at
	* most contain whitespace characters like space and tab.
	* <p>
	* The input file is a plain text CSV file with the semicolon as field separator and double quotes as field delimiters
	* and three columns. See {@link #getDataSet(ExecutionEnvironment)} for configuration.
	* <p>
	* Usage: <code>FilterAndCountIncompleteLines [<input file path> [<result path>]]</code> <br>
	* <p>
	* This example shows how to use:
	* <ul>
	* <li>custom accumulators
	* <li>tuple data types
	* <li>inline-defined functions
	* </ul>
	*/
	@SuppressWarnings("serial")
	public class EmptyFieldsCountAccumulator {

	// *************************************************************************
	// PROGRAM
	// *************************************************************************

	private static final String EMPTY_FIELD_ACCUMULATOR = "empty-fields";

	public static void main(final String[] args) throws Exception {

	if (!parseParameters(args)) {
	return;
	}

	final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

	// get the data set
	final DataSet<Tuple> file = getDataSet(env);

	// filter lines with empty fields
	final DataSet<Tuple> filteredLines = file.filter(new EmptyFieldFilter());

	// Here, we could do further processing with the filtered lines...
	JobExecutionResult result;
	// output the filtered lines
	if (outputPath == null) {
	filteredLines.print();
	result = env.getLastJobExecutionResult();
	} else {
	filteredLines.writeAsCsv(outputPath);
	// execute program
	result = env.execute("Accumulator example");
	}

	// get the accumulator result via its registration key
	final List<Integer> emptyFields = result.getAccumulatorResult(EMPTY_FIELD_ACCUMULATOR);
	System.out.format("Number of detected empty fields per column: %s\n", emptyFields);
	}

	// *************************************************************************
	// UTIL METHODS
	// *************************************************************************

	private static String filePath;
	private static String outputPath;

	private static boolean parseParameters(final String[] programArguments) {

	if (programArguments.length >= 3) {
	System.err.println("Usage: FilterAndCountIncompleteLines [<input file path> [<result path>]]");
	return false;
	}

	if (programArguments.length >= 1) {
	filePath = programArguments[0];
	if (programArguments.length == 2) {
	outputPath = programArguments[1];
	}
	}

	return true;
	}

	@SuppressWarnings("unchecked")
	private static DataSet<Tuple> getDataSet(final ExecutionEnvironment env) {

	DataSet<? extends Tuple> source;
	if (filePath == null) {
	source = env.fromCollection(getExampleInputTuples());

	} else {
	source = env
	.readCsvFile(filePath)
	.fieldDelimiter(";")
	.types(String.class, String.class, String.class);

	}

	return (DataSet<Tuple>) source;
	}

	private static Collection<Tuple3<String, String, String>> getExampleInputTuples() {
	Collection<Tuple3<String, String, String>> inputTuples = new ArrayList<Tuple3<String, String, String>>();
	inputTuples.add(new Tuple3<String, String, String>("John", "Doe", "Foo Str."));
	inputTuples.add(new Tuple3<String, String, String>("Joe", "Johnson", ""));
	inputTuples.add(new Tuple3<String, String, String>(null, "Kate Morn", "Bar Blvd."));
	inputTuples.add(new Tuple3<String, String, String>("Tim", "Rinny", ""));
	inputTuples.add(new Tuple3<String, String, String>("Alicia", "Jackson", " "));
	return inputTuples;
	}

	/**
	* This function filters all incoming tuples that have one or more empty fields.
	* In doing so, it also counts the number of empty fields per attribute with an accumulator (registered under
	* {@link EmptyFieldsCountAccumulator#EMPTY_FIELD_ACCUMULATOR}).
	*/
	public static final class EmptyFieldFilter extends RichFilterFunction<Tuple> {

	// create a new accumulator in each filter function instance
	// accumulators can be merged later on
	private final VectorAccumulator emptyFieldCounter = new VectorAccumulator();

	@Override
	public void open(final Configuration parameters) throws Exception {
	super.open(parameters);

	// register the accumulator instance
	getRuntimeContext().addAccumulator(EMPTY_FIELD_ACCUMULATOR,
	this.emptyFieldCounter);
	}

	@Override
	public boolean filter(final Tuple t) {
	boolean containsEmptyFields = false;

	// iterate over the tuple fields looking for empty ones
	for (int pos = 0; pos < t.getArity(); pos++) {

	final String field = t.getField(pos);
	if (field == null \|\| field.trim().isEmpty()) {
	containsEmptyFields = true;

	// if an empty field is encountered, update the
	// accumulator
	this.emptyFieldCounter.add(pos);
	}
	}

	return !containsEmptyFields;
	}
	}

	/**
	* This accumulator lets you increase vector components distributedly. The {@link #add(Integer)} method lets you
	* increase the <i>n</i>-th vector component by 1, whereat <i>n</i> is the methods parameter. The size of the vector
	* is automatically managed.
	*/
	public static class VectorAccumulator implements Accumulator<Integer, ArrayList<Integer>> {

	/** Stores the accumulated vector components. */
	private final ArrayList<Integer> resultVector;

	public VectorAccumulator(){
	this(new ArrayList<Integer>());
	}

	public VectorAccumulator(ArrayList<Integer> resultVector){
	this.resultVector = resultVector;
	}

	/**
	* Increases the result vector component at the specified position by 1.
	*/
	@Override
	public void add(Integer position) {
	updateResultVector(position, 1);
	}

	/**
	* Increases the result vector component at the specified position by the specified delta.
	*/
	private void updateResultVector(int position, int delta) {
	// inflate the vector to contain the given position
	while (this.resultVector.size() <= position) {
	this.resultVector.add(0);
	}

	// increment the component value
	final int component = this.resultVector.get(position);
	this.resultVector.set(position, component + delta);
	}

	@Override
	public ArrayList<Integer> getLocalValue() {
	return this.resultVector;
	}

	@Override
	public void resetLocal() {
	// clear the result vector if the accumulator instance shall be reused
	this.resultVector.clear();
	}

	@Override
	public void merge(final Accumulator<Integer, ArrayList<Integer>> other) {
	// merge two vector accumulators by adding their up their vector components
	final List<Integer> otherVector = other.getLocalValue();
	for (int index = 0; index < otherVector.size(); index++) {
	updateResultVector(index, otherVector.get(index));
	}
	}

	@Override
	public Accumulator<Integer, ArrayList<Integer>> clone() {
	return new VectorAccumulator(new ArrayList<Integer>(resultVector));
	}

	@Override
	public String toString() {
	return StringUtils.join(resultVector, ',');
	}
	}
	}