/*
* Copyright 2010 Keith Stevens
*
* This file is part of the S-Space package and is covered under the terms and
* conditions therein.
*
* The S-Space package is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation and distributed hereunder to you.
*
* THIS SOFTWARE IS PROVIDED "AS IS" AND NO REPRESENTATIONS OR WARRANTIES,
* EXPRESS OR IMPLIED ARE MADE. BY WAY OF EXAMPLE, BUT NOT LIMITATION, WE MAKE
* NO REPRESENTATIONS OR WARRANTIES OF MERCHANT- ABILITY OR FITNESS FOR ANY
* PARTICULAR PURPOSE OR THAT THE USE OF THE LICENSED SOFTWARE OR DOCUMENTATION
* WILL NOT INFRINGE ANY THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER
* RIGHTS.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package edu.ucla.sspace.text;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOError;
import java.io.IOException;
import java.util.Iterator;
/**
* An iterator implementation that returns {@link Document} containg a single
* dependency parsed sentence given a file in the <a
* href="http://nextens.uvt.nl/depparse-wiki/DataFormat">CoNLL Format</a>
*
* <p>
*
* This class is thread-safe.
*/
public class UkWacDependencyFileIterator implements Iterator<Document> {
/**
* The reader for accessing the file containing the documents
*/
private final BufferedReader documentsReader;
/**
* The next line in the file
*/
private String nextLine;
/**
* Creates an {@code Iterator} over the file where each document returned
* contains the sequence of dependency parsed words composing a sentence..
*
* @param documentsFile the file specifying a dependency parsed file in the
* <a href="http://nextens.uvt.nl/depparse-wiki/DataFormat">CoNLL Format</a>
*
* @throws IOException if any error occurs when reading
* {@code documentsFile}
*/
public UkWacDependencyFileIterator(String documentsFile)
throws IOException {
documentsReader = new BufferedReader(new FileReader(documentsFile));
nextLine = advance();
}
/**
* Returns {@code true} if there are more documents to return.
*/
public boolean hasNext() {
return nextLine != null;
}
private String advance() throws IOException {
StringBuilder sb = new StringBuilder();
String line = null;
// Read the <text line. Or read the end of the file and finish the
// iteration.
if (documentsReader.readLine() == null)
return null;
while ((line = documentsReader.readLine()) != null
&& !line.equals("</text>")) {
// Skip sentence delimitors. Also, sometimes the <text/> tags are
// interleaved with <s/> tags, so check against those too.
if (line.startsWith("<s>") || line.startsWith("</s>")
|| line.startsWith("<text"))
continue;
// Append the token line, while avoiding blank lines that seemingly
// creep into the corpus.
if (line.length() > 0)
sb.append(line).append("\n");
}
return sb.toString();
}
/**
* Returns the next document from the file.
*/
public synchronized Document next() {
Document next = new StringDocument(nextLine);
try {
nextLine = advance();
} catch (IOException ioe) {
throw new IOError(ioe);
}
return next;
}
/**
* Throws an {@link UnsupportedOperationException} if called.
*/
public void remove() {
throw new UnsupportedOperationException(
"removing documents is not supported");
}
}