opennlp.tools.doccat.DocumentSampleStream Maven / Gradle / Ivy
/*
* 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 opennlp.tools.doccat;
import java.io.IOException;
import opennlp.tools.tokenize.WhitespaceTokenizer;
import opennlp.tools.util.FilterObjectStream;
import opennlp.tools.util.ObjectStream;
/**
* This class reads in string encoded training samples, parses them and outputs {@link DocumentSample} objects.
*
* Format:
* Each line contains one sample document.
* The category is the first string in the line followed by a tab and whitespace separated document tokens.
* Sample line: category-string tab-char whitespace-separated-tokens line-break-char(s)
*/
public class DocumentSampleStream extends FilterObjectStream {
public DocumentSampleStream(ObjectStream samples) {
super(samples);
}
public DocumentSample read() throws IOException {
String sampleString = samples.read();
if (sampleString != null) {
// Whitespace tokenize entire string
String tokens[] = WhitespaceTokenizer.INSTANCE.tokenize(sampleString);
DocumentSample sample;
if (tokens.length > 1) {
String category = tokens[0];
String docTokens[] = new String[tokens.length - 1];
System.arraycopy(tokens, 1, docTokens, 0, tokens.length -1);
sample = new DocumentSample(category, docTokens);
}
else {
throw new IOException("Empty lines, or lines with only a category string are not allowed!");
}
return sample;
}
else {
return null;
}
}
}