directoryiomanager.java

Mandarax是一个规则引擎的纯Java实现。它支持多类型的事实和基于反映的规则

/*
 * Copyright (C) 1999-2005 <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</a>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package org.mandarax.zkb;

import java.util.Properties;
import java.io.*;

/**
 * IO Manager implementation based on directories.
 * @author <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</A>
 * @version 3.4 <7 March 05>
 * @since 3.4
 */

public class DirectoryIOManager extends AbstractIOManager{
	/**
	 * Write zkb data.
	 * @param target an object describing the target (e.g. a file)
	 * @param metaData the serialized meta data
	 * @param kbData the serialized knowledge base
	 * @param ops the object persistency service used
	 * @param resourceData the serialized resource data (objects)
	 */
	public void write(Object target,byte[] metaData, byte[] kbData, byte[] resourceData,ObjectPersistencyService ops) throws Exception {
		OutputStream out = null;
		File dir = null;
		if (target instanceof File) {
			dir = (File)target;
			if (!dir.isDirectory()) throw new IllegalArgumentException("target must be a directory");
		}
		else throw new IllegalArgumentException("This target type is not support: " + target);

		File f = this.getFile(dir,META);
		out = new FileOutputStream(f);
		out.write(metaData);
		out.close();
		
		f = this.getFile(dir,RESOURCES + "." + ops.getExtension());
		out = new FileOutputStream(f);
		out.write(resourceData);
		out.close();
		
		f = this.getFile(dir,KB);
		out = new FileOutputStream(f);
		out.write(kbData);
		out.close();

		out.close();
		
	}
	
	/**
	 * Read zkb data.
	 * @param source the data source (e.g., a file)
	 * @return a data object
	 */
	public Data read(Object source) throws Exception {
		Data result = new Data();
		File dir = null;
		
		if (source instanceof File) {
			dir = (File)source;
			if (!dir.isDirectory()) {
				throw new IllegalArgumentException("target must be a directory");
			}
		}
		else throw new IllegalArgumentException("This source type is not support: " + source);

		
		// meta data
		byte[] metaData = readFromFile(dir,META);
		
		// read extension for resource file from meta data
		result.metaData = new Properties();
		result.metaData.load(new ByteArrayInputStream(metaData));
		result.ops = getOPS(result.metaData);
		
		result.resourceData = readFromFile(dir,RESOURCES+"."+result.ops.getExtension());
		result.kbData = readFromFile(dir,KB);
		
		return result;
	}
	/**
	 * Get the file.
	 * @param folder a folder
	 * @param fileName a file name
	 */
	private File getFile(File folder,String fileName) {
		return new File(folder,fileName);
	}
	/**
	 * Read data from a file.
	 * @param dir the folder
	 * @param fileName the file name
	 */
	private byte[] readFromFile(File dir,String fileName) throws IOException {
		File f = getFile(dir,fileName);
		FileInputStream in = new FileInputStream(f);
		byte[] data = this.readData(in);
		in.close();
		return data;
	}

}