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/>. */ /* * SerializedObject.java * Copyright (C) 2001-2012 University of Waikato, Hamilton, New Zealand * */ package weka.core; import weka.core.scripting.Jython; import weka.core.scripting.JythonSerializableObject; import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.ObjectStreamClass; import java.io.OutputStream; import java.io.Serializable; import java.util.LinkedHashSet; import java.util.Set; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; /** * Class for storing an object in serialized form in memory. It can be used to * make deep copies of objects, and also allows compression to conserve memory. * <p> * * @author Richard Kirkby (rbk1@cs.waikato.ac.nz) * @version $Revision$ */ public class SerializedObject implements Serializable, RevisionHandler { /** for serialization */ private static final long serialVersionUID = 6635502953928860434L; /** The array storing the object. */ private byte[] m_storedObjectArray; /** Whether or not the object is compressed. */ private boolean m_isCompressed; /** Whether it is a Jython object or not */ private boolean m_isJython; /** * Creates a new serialized object (without compression). * * @param toStore the object to store * @exception Exception if the object couldn't be serialized */ public SerializedObject(Object toStore) throws Exception { this(toStore, false); } /** * Creates a new serialized object. * * @param toStore the object to store * @param compress whether or not to use compression * @exception Exception if the object couldn't be serialized */ public SerializedObject(Object toStore, boolean compress) throws Exception { ByteArrayOutputStream ostream = new ByteArrayOutputStream(); OutputStream os = ostream; ObjectOutputStream p; if (!compress) p = new ObjectOutputStream(new BufferedOutputStream(os)); else p = new ObjectOutputStream(new BufferedOutputStream(new GZIPOutputStream(os))); p.writeObject(toStore); p.flush(); p.close(); // used to be ostream.close() ! m_storedObjectArray = ostream.toByteArray(); m_isCompressed = compress; m_isJython = (toStore instanceof JythonSerializableObject); } /* * Checks to see whether this object is equal to another. * * @param compareTo the object to compare to * * @return whether or not the objects are equal */ public final boolean equals(Object compareTo) { if (compareTo == null) return false; if (!compareTo.getClass().equals(this.getClass())) return false; byte[] compareArray = ((SerializedObject) compareTo).m_storedObjectArray; if (compareArray.length != m_storedObjectArray.length) return false; for (int i = 0; i < compareArray.length; i++) { if (compareArray[i] != m_storedObjectArray[i]) return false; } return true; } /** * Returns a hashcode for this object. * * @return the hashcode */ public int hashCode() { return m_storedObjectArray.length; } /** * Returns a serialized object. Uses org.python.util.PythonObjectInputStream * for Jython objects (read <a * href="http://aspn.activestate.com/ASPN/Mail/Message/Jython-users/1001401" * >here</a> for more details). * * @return the restored object */ public Object getObject() { try { ByteArrayInputStream istream = new ByteArrayInputStream(m_storedObjectArray); ObjectInputStream p; Object toReturn = null; if (m_isJython) { if (!m_isCompressed) toReturn = Jython.deserialize(new BufferedInputStream(istream)); else toReturn = Jython.deserialize(new BufferedInputStream(new GZIPInputStream(istream))); } else { if (!m_isCompressed) p = new ObjectInputStream(new BufferedInputStream(istream)) { protected Set<WekaPackageLibIsolatingClassLoader> m_thirdPartyLoaders = new LinkedHashSet<>(); @Override protected Class<?> resolveClass(ObjectStreamClass desc) throws IOException, ClassNotFoundException { // make sure that the type descriptor for arrays gets removed from // what we're going to look up! String arrayStripped = desc.getName().replace("[L", "").replace("[", "").replace(";", ""); ClassLoader cl = WekaPackageClassLoaderManager.getWekaPackageClassLoaderManager() .getLoaderForClass(arrayStripped); if (cl instanceof WekaPackageLibIsolatingClassLoader) { // might be third-party classes involved, store the classloader m_thirdPartyLoaders.add((WekaPackageLibIsolatingClassLoader) cl); } Class<?> result = null; try { result = Class.forName(desc.getName(), true, cl); } catch (ClassNotFoundException ex) { for (WekaPackageLibIsolatingClassLoader l : m_thirdPartyLoaders) { ClassLoader checked = SerializationHelper.checkForThirdPartyClass(arrayStripped, l); if (checked != null) { result = Class.forName(desc.getName(), true, checked); } } } if (result == null) { result = super.resolveClass(desc); if (result == null) { throw new ClassNotFoundException("Unable to find class " + arrayStripped); } } return result; } }; else p = new ObjectInputStream(new BufferedInputStream(new GZIPInputStream(istream))) { protected Set<WekaPackageLibIsolatingClassLoader> m_thirdPartyLoaders = new LinkedHashSet<>(); protected WekaPackageLibIsolatingClassLoader m_firstLoader = null; @Override protected Class<?> resolveClass(ObjectStreamClass desc) throws IOException, ClassNotFoundException { // make sure that the type descriptor for arrays gets removed // from what we're going to look up! String arrayStripped = desc.getName().replace("[L", "").replace("[", "").replace(";", ""); ClassLoader cl = WekaPackageClassLoaderManager.getWekaPackageClassLoaderManager() .getLoaderForClass(arrayStripped); if (cl instanceof WekaPackageLibIsolatingClassLoader) { // might be third-party classes involved, store the // classloader m_thirdPartyLoaders.add((WekaPackageLibIsolatingClassLoader) cl); } Class<?> result = null; try { result = Class.forName(desc.getName(), true, cl); } catch (ClassNotFoundException ex) { for (WekaPackageLibIsolatingClassLoader l : m_thirdPartyLoaders) { ClassLoader checked = SerializationHelper.checkForThirdPartyClass(arrayStripped, l); if (checked != null) { result = Class.forName(desc.getName(), true, checked); } } } if (result == null) { result = super.resolveClass(desc); if (result == null) { throw new ClassNotFoundException("Unable to find class " + arrayStripped); } } return result; } }; toReturn = p.readObject(); } istream.close(); return toReturn; } catch (Exception e) { e.printStackTrace(); return null; } } /** * Returns the revision string. * * @return the revision */ public String getRevision() { return RevisionUtils.extract("$Revision$"); } }