walterddr commented on a change in pull request #9355: [FLINK-13577][ml] Add an util class to build result row and generate … URL: https://github.com/apache/flink/pull/9355#discussion_r355205368
########## File path: flink-ml-parent/flink-ml-lib/src/main/java/org/apache/flink/ml/common/utils/OutputColsHelper.java ########## @@ -0,0 +1,200 @@ +/* + * 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.ml.common.utils; + +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.table.api.TableSchema; +import org.apache.flink.types.Row; + +import org.apache.commons.lang3.ArrayUtils; + +import java.io.Serializable; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.HashSet; + +/** + * Utils for merging input data with output data. + * + * <p>Input: + * 1) Schema of input data being predicted or transformed. + * 2) Output column names of the prediction/transformation operator. + * 3) Output column types of the prediction/transformation operator. + * 4) Reserved column names, which is a subset of input data's column names that we want to preserve. + * + * <p>Output: + * 1）The result data schema. The result data is a combination of the preserved columns and the operator's + * output columns. + * + * <p>Several rules are followed: + * 1) If reserved columns are not given, then all columns of input data is reserved. + * 2）The reserved columns are arranged ahead of the operator's output columns in the final output. + * 3) If some of the reserved column names overlap with those of operator's output columns, then the operator's + * output columns override the conflicting reserved columns. + * 4) The reserved columns in the result table preserve their orders as in the input table. + * + * <p>For example, if we have input data schema of ["id":INT, "f1":FLOAT, "f2":DOUBLE], and the operator outputs + * a column "label" with type STRING, and we want to preserve the column "id", then we get the result + * schema of ["id":INT, "label":STRING]. + * + * <p>end user should not directly interact with this helper class. instead it will be indirectly used via concrete algorithms. + */ +public class OutputColsHelper implements Serializable { + private String[] inputColNames; + private TypeInformation[] inputColTypes; + private String[] outputColNames; + private TypeInformation[] outputColTypes; + + /** + * Column indices in the input data that would be forward to the result. + */ + private int[] reservedCols; + + /** + * The positions of reserved columns in the result. + */ + private int[] reservedColsPosInResult; + + /** + * The positions of output columns in the result. + */ + private int[] outputColsPosInResult; + + public OutputColsHelper(TableSchema inputSchema, String outputColName, TypeInformation outputColType) { + this(inputSchema, outputColName, outputColType, inputSchema.getFieldNames()); + } + + public OutputColsHelper(TableSchema inputSchema, String outputColName, TypeInformation outputColType, + String[] reservedColNames) { + this(inputSchema, new String[]{outputColName}, new TypeInformation[]{outputColType}, reservedColNames); + } + + public OutputColsHelper(TableSchema inputSchema, String[] outputColNames, TypeInformation[] outputColTypes) { + this(inputSchema, outputColNames, outputColTypes, inputSchema.getFieldNames()); + } + + /** + * The constructor. + * + * @param inputSchema Schema of input data being predicted or transformed. + * @param outputColNames Output column names of the prediction/transformation operator. + * @param outputColTypes Output column types of the prediction/transformation operator. + * @param reservedColNames Reserved column names, which is a subset of input data's column names that we want to preserve. + */ + public OutputColsHelper(TableSchema inputSchema, String[] outputColNames, TypeInformation[] outputColTypes, + String[] reservedColNames) { + this.inputColNames = inputSchema.getFieldNames(); + this.inputColTypes = inputSchema.getFieldTypes(); + this.outputColNames = outputColNames; + this.outputColTypes = outputColTypes; + + HashSet<String> toReservedCols = new HashSet<>( + Arrays.asList(reservedColNames == null ? this.inputColNames : reservedColNames) + ); + //the indices of the columns which need to be reserved. + ArrayList<Integer> reservedColIndices = new ArrayList<>(toReservedCols.size()); + ArrayList<Integer> reservedColToResultIndex = new ArrayList<>(toReservedCols.size()); + outputColsPosInResult = new int[outputColNames.length]; + Arrays.fill(outputColsPosInResult, -1); + int index = 0; + for (int i = 0; i < inputColNames.length; i++) { + int key = ArrayUtils.indexOf(outputColNames, inputColNames[i]); + if (key >= 0) { + outputColsPosInResult[key] = index++; + continue; + } + //add these interested column. + if (toReservedCols.contains(inputColNames[i])) { + reservedColIndices.add(i); + reservedColToResultIndex.add(index++); + } + } + for (int i = 0; i < outputColsPosInResult.length; i++) { + if (outputColsPosInResult[i] == -1) { + outputColsPosInResult[i] = index++; + } + } + //write reversed column information in array. + this.reservedCols = new int[reservedColIndices.size()]; + this.reservedColsPosInResult = new int[reservedColIndices.size()]; + for (int i = 0; i < this.reservedCols.length; i++) { + this.reservedCols[i] = reservedColIndices.get(i); + this.reservedColsPosInResult[i] = reservedColToResultIndex.get(i); + } + } + + /** + * Get the reserved columns' names. + * + * @return the reserved colNames. + */ + public String[] getReservedColumns() { Review comment: API is not tested. I made some changes to the test in https://github.com/walterddr/flink/commit/802fa4c6530d90b6322c7be548b0953f17cbf003 ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
