yunfengzhou-hub commented on code in PR #153: URL: https://github.com/apache/flink-ml/pull/153#discussion_r963180773
########## flink-ml-lib/src/main/java/org/apache/flink/ml/feature/ngram/NGram.java: ########## @@ -0,0 +1,99 @@ +/* + * 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.feature.ngram; + +import org.apache.flink.ml.api.Transformer; +import org.apache.flink.ml.param.Param; +import org.apache.flink.ml.util.ParamUtils; +import org.apache.flink.ml.util.ReadWriteUtils; +import org.apache.flink.table.api.Expressions; +import org.apache.flink.table.api.Table; +import org.apache.flink.table.api.bridge.java.StreamTableEnvironment; +import org.apache.flink.table.expressions.Expression; +import org.apache.flink.table.functions.ScalarFunction; +import org.apache.flink.util.Preconditions; + +import java.io.IOException; +import java.util.HashMap; +import java.util.Map; + +import static org.apache.flink.table.api.Expressions.$; + +/** + * A Transformer that converts the input string array into an array of n-grams, where each n-gram is + * represented by a space-separated string of words. If the length of the input array is less than + * `n`, no n-grams are returned. + */ +public class NGram implements Transformer<NGram>, NGramParams<NGram> { + private final Map<Param<?>, Object> paramMap = new HashMap<>(); + + public NGram() { + ParamUtils.initializeMapWithDefaultValues(paramMap, this); + } + + @Override + public Table[] transform(Table... inputs) { + Preconditions.checkArgument(inputs.length == 1); + Expression nGramUdf = + Expressions.call(NGramUdf.class, $(getInputCol()), getN()).as(getOutputCol()); + Table output = inputs[0].addColumns(nGramUdf); + return new Table[] {output}; + } + + @Override + public void save(String path) throws IOException { + ReadWriteUtils.saveMetadata(this, path); + } + + @Override + public Map<Param<?>, Object> getParamMap() { + return paramMap; + } + + public static NGram load(StreamTableEnvironment tEnv, String path) throws IOException { + return ReadWriteUtils.loadStageParam(path); + } + + /** + * The main logic of ${@link NGram}, which converts the input string array to an array of Review Comment: nit: the "$" mark is unnecessary. ########## flink-ml-lib/src/main/java/org/apache/flink/ml/feature/ngram/NGram.java: ########## @@ -0,0 +1,99 @@ +/* + * 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.feature.ngram; + +import org.apache.flink.ml.api.Transformer; +import org.apache.flink.ml.param.Param; +import org.apache.flink.ml.util.ParamUtils; +import org.apache.flink.ml.util.ReadWriteUtils; +import org.apache.flink.table.api.Expressions; +import org.apache.flink.table.api.Table; +import org.apache.flink.table.api.bridge.java.StreamTableEnvironment; +import org.apache.flink.table.expressions.Expression; +import org.apache.flink.table.functions.ScalarFunction; +import org.apache.flink.util.Preconditions; + +import java.io.IOException; +import java.util.HashMap; +import java.util.Map; + +import static org.apache.flink.table.api.Expressions.$; + +/** + * A Transformer that converts the input string array into an array of n-grams, where each n-gram is + * represented by a space-separated string of words. If the length of the input array is less than + * `n`, no n-grams are returned. Review Comment: nit: Let's add a wiki link here. -- 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. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
