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/*
 * 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.tools.text;

import static hivemall.utils.hadoop.WritableUtils.val;

import java.util.Arrays;

import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.hive.ql.udf.UDFType;
import org.apache.hadoop.io.BooleanWritable;

@Description(name = "is_stopword",
        value = "_FUNC_(string word) - Returns whether English stopword or not")
@UDFType(deterministic = true, stateful = false)
public final class StopwordUDF extends UDF {

    private static final String[] stopwords;
    static {
        stopwords = new String[] {"i", "me", "my", "myself", "we", "our", "ours", "ourselves",
                "you", "your", "yours", "yourself", "yourselves", "he", "him", "his", "himself",
                "she", "her", "hers", "herself", "it", "its", "itself", "they", "them", "their",
                "theirs", "themselves", "what", "which", "who", "whom", "this", "that", "these",
                "those", "am", "is", "are", "was", "were", "be", "been", "being", "have", "has",
                "had", "having", "do", "does", "did", "doing", "a", "an", "the", "and", "but", "if",
                "or", "because", "as", "until", "while", "of", "at", "by", "for", "with", "about",
                "against", "between", "into", "through", "during", "before", "after", "above",
                "below", "to", "from", "up", "down", "in", "out", "on", "off", "over", "under",
                "again", "further", "then", "once", "here", "there", "when", "where", "why", "how",
                "all", "any", "both", "each", "few", "more", "most", "other", "some", "such", "no",
                "nor", "not", "only", "own", "same", "so", "than", "too", "very", "s", "t", "can",
                "will", "just", "don", "should", "now"};
        Arrays.sort(stopwords);
    }

    public BooleanWritable evaluate(String word) {
        return val(Arrays.binarySearch(stopwords, word) >= 0);
    }

}