Java tutorial
/* * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* * KOML.java * Copyright (C) 2004-2012 University of Waikato, Hamilton, New Zealand */ package weka.core.xml; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import weka.core.RevisionHandler; import weka.core.RevisionUtils; /** * This class is a helper class for XML serialization using <a * href="http://koala.ilog.fr/XML/serialization/" target="_blank">KOML</a> . * KOML does not need to be present, since the class-calls are done generically * via Reflection. * * @author FracPete (fracpete at waikato dot ac dot nz) * @version $Revision 1.0$ */ public class KOML implements RevisionHandler { /** * indicates whether <a href="http://koala.ilog.fr/XML/serialization/" * target="_blank">KOML</a> (Koala Object Markup Language) is present */ protected static boolean m_Present = false; /** the extension for KOML files (including '.') */ public final static String FILE_EXTENSION = ".koml"; /** check for KOML statically (needs only to be done once) */ static { checkForKOML(); } /** * checks whether the KOML is present in the class path */ private static void checkForKOML() { try { Class.forName("fr.dyade.koala.xml.koml.KOMLSerializer"); m_Present = true; } catch (Exception e) { m_Present = false; } } /** * returns whether KOML is present or not, i.e. whether the classes are in the * classpath or not * * @return whether KOML is available */ public static boolean isPresent() { return m_Present; } /** * reads the XML-serialized object from the given file * * @param filename the file to deserialize the object from * @return the deserialized object * @throws Exception if something goes wrong while reading from the file */ public static Object read(String filename) throws Exception { return read(new FileInputStream(filename)); } /** * reads the XML-serialized object from the given file * * @param file the file to deserialize the object from * @return the deserialized object * @throws Exception if something goes wrong while reading from the file */ public static Object read(File file) throws Exception { return read(new FileInputStream(file)); } /** * reads the XML-serialized object from a stream * * @param stream the stream to deserialize the object from * @return the deserialized object * @throws Exception if something goes wrong while reading from the stream */ public static Object read(InputStream stream) throws Exception { Class<?> komlClass; Class<?>[] komlClassArgs; Object[] komlArgs; java.lang.reflect.Constructor<?> constructor; Object koml; java.lang.reflect.Method methodRead; java.lang.reflect.Method methodClose; Class<?>[] readArgsClasses; Class<?>[] closeArgsClasses; Object[] readArgs; Object[] closeArgs; Object result; result = null; // get Deserializer komlClass = Class.forName("fr.dyade.koala.xml.koml.KOMLDeserializer"); komlClassArgs = new Class[2]; komlClassArgs[0] = java.io.InputStream.class; komlClassArgs[1] = Boolean.TYPE; komlArgs = new Object[2]; komlArgs[0] = stream; komlArgs[1] = new Boolean(false); constructor = komlClass.getConstructor(komlClassArgs); koml = constructor.newInstance(komlArgs); readArgsClasses = new Class[0]; methodRead = komlClass.getMethod("readObject", readArgsClasses); readArgs = new Object[0]; closeArgsClasses = new Class[0]; methodClose = komlClass.getMethod("close", closeArgsClasses); closeArgs = new Object[0]; // execute it try { result = methodRead.invoke(koml, readArgs); } catch (Exception e) { result = null; } finally { methodClose.invoke(koml, closeArgs); } return result; } /** * writes the XML-serialized object to the given file * * @param filename the file to serialize the object to * @param o the object to write to the file * @return whether writing was successful or not * @throws Exception if something goes wrong while writing to the file */ public static boolean write(String filename, Object o) throws Exception { return write(new FileOutputStream(filename), o); } /** * write the XML-serialized object to the given file * * @param file the file to serialize the object to * @param o the object to write to the file * @return whether writing was successful or not * @throws Exception if something goes wrong while writing to the file */ public static boolean write(File file, Object o) throws Exception { return write(new FileOutputStream(file), o); } /** * writes the XML-serialized object to a stream * * @param stream the stream to serialize the object to * @param o the object to write to the stream * @return whether writing was successful or not * @throws Exception if something goes wrong while writing to the stream */ public static boolean write(OutputStream stream, Object o) throws Exception { Class<?> komlClass; Class<?>[] komlClassArgs; Object[] komlArgs; java.lang.reflect.Constructor<?> constructor; Object koml; java.lang.reflect.Method methodAdd; java.lang.reflect.Method methodClose; Class<?>[] addArgsClasses; Class<?>[] closeArgsClasses; Object[] addArgs; Object[] closeArgs; boolean result; result = false; // get Deserializer komlClass = Class.forName("fr.dyade.koala.xml.koml.KOMLSerializer"); komlClassArgs = new Class[2]; komlClassArgs[0] = java.io.OutputStream.class; komlClassArgs[1] = Boolean.TYPE; komlArgs = new Object[2]; komlArgs[0] = stream; komlArgs[1] = new Boolean(false); constructor = komlClass.getConstructor(komlClassArgs); koml = constructor.newInstance(komlArgs); addArgsClasses = new Class[1]; addArgsClasses[0] = Object.class; methodAdd = komlClass.getMethod("addObject", addArgsClasses); addArgs = new Object[1]; addArgs[0] = o; closeArgsClasses = new Class[0]; methodClose = komlClass.getMethod("close", closeArgsClasses); closeArgs = new Object[0]; // execute it try { methodAdd.invoke(koml, addArgs); result = true; } catch (Exception e) { result = false; } finally { methodClose.invoke(koml, closeArgs); } return result; } /** * Returns the revision string. * * @return the revision */ @Override public String getRevision() { return RevisionUtils.extract("$Revision$"); } }