org.dkpro.tc.ml.svmhmm.util.CommentsIterator.java Source code

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Here is the source code for org.dkpro.tc.ml.svmhmm.util.CommentsIterator.java

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/*
 * Copyright 2016
 * Ubiquitous Knowledge Processing (UKP) Lab
 * Technische Universitt Darmstadt
 *
 * Licensed 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.dkpro.tc.ml.svmhmm.util;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.lang.StringUtils;

public class CommentsIterator implements Iterator<List<String>> {
    private BufferedReader br = null;
    private String line = null;

    public CommentsIterator(File f) throws IOException {
        br = new BufferedReader(new InputStreamReader(new FileInputStream(f)));

    }

    @Override
    public boolean hasNext() {
        try {
            line = br.readLine();
        } catch (IOException e) {
            throw new UnsupportedOperationException(new IOException(e));
        }

        boolean result = line != null;
        if (!result) {
            try {
                br.close();
            } catch (IOException e) {
                throw new UnsupportedOperationException(new IOException(e));
            }
        }

        return result;
    }

    @Override
    public List<String> next() {

        String comment = null;
        try {
            comment = extractComment(line);
        } catch (Exception e1) {
            throw new UnsupportedOperationException(e1);
        }

        List<String> list = new ArrayList<>();

        String[] tokens = comment.split("\\s+");
        // filter empty tokens
        for (String token : tokens) {
            String trim = token.trim();
            if (!trim.isEmpty()) {
                // decode from URL representation
                String s = null;
                try {
                    s = URLDecoder.decode(trim, "utf-8");
                } catch (UnsupportedEncodingException e) {
                    throw new UnsupportedOperationException(e);
                }
                list.add(s);
            }
        }
        return list;
    }

    private String extractComment(String rawLine) throws Exception {
        // Ideally there is only one # unless the gold label is #
        // then we have something like [# qid:317 3:1 # # 317 %23]

        // Normal case
        int firstCandidate = rawLine.lastIndexOf("#");
        int countMatches = StringUtils.countMatches(rawLine, "#");
        if (countMatches == 1) {
            return rawLine.substring(firstCandidate + 1);
        }

        // Occurrence of two # as in [O qid:5 2:7 # #IFTHEN O 5]
        int secondCandidate = rawLine.lastIndexOf("#", firstCandidate);
        if (countMatches == 2) {
            return rawLine.substring(secondCandidate);
        }

        // Is there an # before the one we just found and the first
        // character in the line is #, too 
        if (countMatches == 3 && rawLine.charAt(0) == '#') {
            return rawLine.substring(secondCandidate);
        }

        throw new Exception("Encountered an unexpected case when extracting the comments");

    }
}