LogGenerator.java

/*
 * Copyright 2011 Matthias van der Vlies
 *
 *  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 core;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;

import play.Logger;
import play.jobs.Job;
import play.libs.F.Promise;
import play.templates.JavaExtensions;

public class LogGenerator extends Job {

	private BufferedReader bufferedReader;
	private InputStreamReader inputStreamReader;
	private FileInputStream fileInputStream;
	
	public LogGenerator(final String filePath, boolean skipToEnd) throws Exception {
		fileInputStream = new FileInputStream (filePath);
		inputStreamReader = new InputStreamReader(fileInputStream, "utf-8");
		bufferedReader = new BufferedReader(inputStreamReader);
		
		if(skipToEnd) {
			final int skipping = fileInputStream.available() - (10 * 1024);
			bufferedReader.skip(skipping > 0 ? skipping : 0); // skip to end - 10 kilo bytes
		}
	}
	
	public String doJobWithResult() throws Exception {
		while (true) {
		    final String line = bufferedReader.readLine();
		    if (line == null) {
		    	// timeout
		        Thread.sleep(50);
		    }
		    else {
		    	return JavaExtensions.escapeHtml(line) + "<br/>";
		    }
		}
	}
	
	public void close() throws IOException {
		fileInputStream.close();
	}
}