/*
* 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.model;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import opennlp.maxent.GIS;
import opennlp.maxent.io.SuffixSensitiveGISModelWriter;
/**
* Class for using a file of events as an event stream. The format of the file is one event perline with
* each line consisting of outcome followed by contexts (space delimited).
*/
public class FileEventStream extends AbstractEventStream {
BufferedReader reader;
String line;
/**
* Creates a new file event stream from the specified file name.
* @param fileName the name fo the file containing the events.
* @throws IOException When the specified file can not be read.
*/
public FileEventStream(String fileName, String encoding) throws IOException {
if (encoding == null) {
reader = new BufferedReader(new FileReader(fileName));
}
else {
reader = new BufferedReader(new InputStreamReader(new FileInputStream(fileName),encoding));
}
}
public FileEventStream(String fileName) throws IOException {
this(fileName,null);
}
/**
* Creates a new file event stream from the specified file.
* @param file the file containing the events.
* @throws IOException When the specified file can not be read.
*/
public FileEventStream(File file) throws IOException {
reader = new BufferedReader(new InputStreamReader(new FileInputStream(file),"UTF8"));
}
public boolean hasNext() {
try {
return (null != (line = reader.readLine()));
}
catch (IOException e) {
System.err.println(e);
return (false);
}
}
public Event next() {
StringTokenizer st = new StringTokenizer(line);
String outcome = st.nextToken();
int count = st.countTokens();
String[] context = new String[count];
for (int ci = 0; ci < count; ci++) {
context[ci] = st.nextToken();
}
return (new Event(outcome, context));
}
/**
* Generates a string representing the specified event.
* @param event The event for which a string representation is needed.
* @return A string representing the specified event.
*/
public static String toLine(Event event) {
StringBuffer sb = new StringBuffer();
sb.append(event.getOutcome());
String[] context = event.getContext();
for (int ci=0,cl=context.length;ci<cl;ci++) {
sb.append(" "+context[ci]);
}
sb.append(System.getProperty("line.separator"));
return sb.toString();
}
/**
* Trains and writes a model based on the events in the specified event file.
* the name of the model created is based on the event file name.
* @param args eventfile [iterations cuttoff]
* @throws IOException when the eventfile can not be read or the model file can not be written.
*/
public static void main(String[] args) throws IOException {
if (args.length == 0) {
System.err.println("Usage: FileEventStream eventfile [iterations cutoff]");
System.exit(1);
}
int ai=0;
String eventFile = args[ai++];
EventStream es = new FileEventStream(eventFile);
int iterations = 100;
int cutoff = 5;
if (ai < args.length) {
iterations = Integer.parseInt(args[ai++]);
cutoff = Integer.parseInt(args[ai++]);
}
AbstractModel model = GIS.trainModel(es,iterations,cutoff);
new SuffixSensitiveGISModelWriter(model, new File(eventFile+".bin.gz")).persist();
}
}