/*
* JBoss, Home of Professional Open Source
* Copyright 2009 Red Hat Inc. and/or its affiliates and other
* contributors as indicated by the @author tags. All rights reserved.
* See the copyright.txt in the distribution for a full listing of
* individual contributors.
*
* This 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 2.1 of
* the License, or (at your option) any later version.
*
* This software 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 software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.infinispan.marshall;
import org.infinispan.CacheException;
import org.infinispan.commands.ReplicableCommand;
import org.infinispan.factories.GlobalComponentRegistry;
import org.infinispan.io.ExposedByteArrayOutputStream;
import org.infinispan.io.UnsignedNumeric;
import org.infinispan.marshall.jboss.ExtendedRiverUnmarshaller;
import org.infinispan.remoting.transport.Address;
import org.infinispan.transaction.xa.GlobalTransaction;
import org.infinispan.util.Util;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Set;
/**
* Wrapper that wraps cached data, providing lazy deserialization using the calling thread's context class loader.
* <p/>
* The {@link org.infinispan.interceptors.MarshalledValueInterceptor} handles transparent wrapping/unwrapping of cached
* data.
* <p/>
* <b>NOTE:</b> the <t>equals()</tt> method of this class will either compare binary representations (byte arrays) or
* delegate to the wrapped instance's <tt>equals()</tt> method, depending on whether both instances being compared are
* in serialized or deserialized form. If one of the instances being compared is in one form and the other in another
* form, then one instance is either serialized or deserialized, the preference will be to compare object representations,
* unless the instance is {@link #compact(boolean, boolean)}ed and a preference is set accordingly.
* <p/>
* Note also that this will affect the way keys stored in the cache will work, if <tt>storeAsBinary</tt> is used, since
* comparisons happen on the key which will be wrapped by a {@link MarshalledValue}. Implementers of <tt>equals()</tt>
* methods of their keys need to be aware of this.
* <p />
*
* This class can be marshalled either via its externalizer or via the JVM
* serialization. The reason for supporting both methods is to enable
* third-party libraries to be able to marshall/unmarshall them using standard
* JVM serialization rules. The Infinispan marshalling layer will always
* chose the most performant one, aka the externalizer method.
*
* @author Manik Surtani (<a href="mailto:manik@jboss.org">manik@jboss.org</a>)
* @author Mircea.Markus@jboss.com
* @author Galder Zamarreño
* @author Sanne Grinovero
* @see org.infinispan.interceptors.MarshalledValueInterceptor
* @since 4.0
*/
public class MarshalledValue implements Serializable {
volatile protected Object instance;
volatile protected byte[] raw;
volatile protected int serialisedSize = 128; //size of serialized representation: initial value is a guess
volatile private int cachedHashCode = 0;
// by default equals() will test on the instance rather than the byte array if conversion is required.
private transient volatile boolean equalityPreferenceForInstance = true;
// A marshaller is needed at construction time to handle equals/hashCode impls
private transient final StreamingMarshaller marshaller;
public MarshalledValue(Object instance, boolean equalityPreferenceForInstance, StreamingMarshaller marshaller) {
if (instance == null) throw new NullPointerException("Null values cannot be wrapped as MarshalledValues!");
this.instance = instance;
this.equalityPreferenceForInstance = equalityPreferenceForInstance;
this.marshaller = marshaller;
}
private MarshalledValue(byte[] raw, int cachedHashCode, StreamingMarshaller marshaller) {
init(raw, cachedHashCode);
this.marshaller = marshaller;
}
private void init(byte[] raw, int cachedHashCode) {
// for unmarshalling
this.raw = raw;
this.serialisedSize = raw.length;
this.cachedHashCode = cachedHashCode;
}
public synchronized byte[] serialize() {
return serialize0();
}
/**
* Should only be called from a synchronized method
*/
private byte[] serialize0() {
byte[] rawValue = raw;
if (rawValue == null) {
try {
// Do NOT set instance to null over here, since it may be used elsewhere (e.g., in a cache listener).
// this will be compacted by the MarshalledValueInterceptor when the call returns.
ExposedByteArrayOutputStream baos = new ExposedByteArrayOutputStream(this.serialisedSize);
ObjectOutput out = marshaller.startObjectOutput(baos, true, this.serialisedSize);
try {
marshaller.objectToObjectStream(instance, out);
} finally {
marshaller.finishObjectOutput(out);
}
final byte[] buf = baos.getRawBuffer();
final int length = baos.size();
if (buf.length == length) {
// in this case we can avoid duplicating the buffer
rawValue = buf;
}
else {
serialisedSize = length;
rawValue = new byte[length];
System.arraycopy(buf, 0, rawValue, 0, length);
}
raw = rawValue;
} catch (Exception e) {
throw new CacheException("Unable to marshall value " + instance, e);
}
}
return rawValue;
}
public synchronized Object deserialize() {
return deserialize0();
}
/**
* Should only be called from a synchronized method
*/
private Object deserialize0() {
Object instanceValue = instance;
if (instanceValue == null) {
try {
// StreamingMarshaller underneath deals with making sure the right classloader is set.
instanceValue = marshaller.objectFromByteBuffer(raw);
instance = instanceValue;
return instanceValue;
}
catch (Exception e) {
throw new CacheException("Unable to unmarshall value", e);
}
}
return instanceValue;
}
/**
* Compacts the references held by this class to a single reference. If only one representation exists this method
* is a no-op unless the 'force' parameter is used, in which case the reference held is forcefully switched to the
* 'preferred representation'.
* <p/>
* Either way, a call to compact() will ensure that only one representation is held.
* <p/>
*
* @param preferSerializedRepresentation if true and both representations exist, the serialized representation is
* favoured. If false, the deserialized representation is preferred.
* @param force ensures the preferred representation is maintained and the other released,
* even if this means serializing or deserializing.
*/
public synchronized void compact(boolean preferSerializedRepresentation, boolean force) {
// reset the equalityPreference
equalityPreferenceForInstance = true;
Object thisInstance = this.instance;
byte[] thisRaw = this.raw;
if (force) {
if (preferSerializedRepresentation && thisRaw == null) {
// Accessing a synchronized method from an already synchronized
// method is expensive, so delegate to a private not synched method.
thisRaw = serialize0();
}
else if (!preferSerializedRepresentation && thisInstance == null){
// Accessing a synchronized method from an already synchronized
// method is expensive, so delegate to a private not synched method.
thisInstance = deserialize0();
}
}
if (thisInstance != null && thisRaw != null) {
// need to loose one representation!
if (preferSerializedRepresentation) {
//in both branches we first set one then null the other, so that there's always one available
//to read from those methods not being synchronized
raw = thisRaw;
instance = null;
} else {
instance = thisInstance;
raw = null;
}
}
}
public byte[] getRaw() {
byte[] rawValue = raw;
if (rawValue == null){
rawValue = serialize();
}
return rawValue;
}
/**
* Returns the 'cached' instance
*/
public Object get() {
Object value = instance;
if (value == null) {
value = deserialize();
}
return value;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
MarshalledValue that = (MarshalledValue) o;
final boolean preferInstanceEquality = equalityPreferenceForInstance && that.equalityPreferenceForInstance;
// if both versions are serialized or deserialized, just compare the relevant representations,
// but attempt the operations in order to respect the value of equalityPreferenceForInstance
Object thisInstance = this.instance;
Object thatInstance = that.instance;
//test the default equality first so we might skip some work:
if (preferInstanceEquality && thisInstance != null && thatInstance != null) return thisInstance.equals(thatInstance);
byte[] thisRaw = this.raw;
byte[] thatRaw = that.raw;
if (thisRaw != null && thatRaw != null) return Arrays.equals(thisRaw, thatRaw);
if (thisInstance != null && thatInstance != null) return thisInstance.equals(thatInstance);
// if conversion of one representation to the other is necessary, then see which we prefer converting.
if (preferInstanceEquality) {
if (thisInstance == null) {
thisInstance = this.deserialize();
}
if (thatInstance == null) {
thatInstance = that.deserialize();
}
return thisInstance.equals(thatInstance);
} else {
if (thisRaw == null) {
thisRaw = this.serialize();
}
if (thatRaw == null) {
thatRaw = that.serialize();
}
return Arrays.equals(thisRaw, thatRaw);
}
}
@Override
public int hashCode() {
//make a local copy to avoid multiple read/writes on the volatile field
int value = cachedHashCode;
if (value == 0) {
Object localInstance = deserialize();
value = localInstance.hashCode();
if (value == 0) // degenerate case
{
value = 0xFEED;
}
cachedHashCode = value;
}
return value;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder()
.append("MarshalledValue{")
.append("instance=").append(instance != null ? instance.toString() : "<serialized>")
.append(", serialized=").append(raw != null ? Util.printArray(raw, false) : "false")
.append(", cachedHashCode=").append(cachedHashCode)
.append("}@").append(Util.hexIdHashCode(this));
return sb.toString();
}
public MarshalledValue setEqualityPreferenceForInstance(boolean equalityPreferenceForInstance) {
this.equalityPreferenceForInstance = equalityPreferenceForInstance;
return this;
}
/**
* Tests whether the type should be excluded from MarshalledValue wrapping.
*
* @param type type to test. Should not be null.
* @return true if it should be excluded from MarshalledValue wrapping.
*/
public static boolean isTypeExcluded(Class<?> type) {
return type.equals(String.class) || type.isPrimitive() ||
type.equals(Void.class) || type.equals(Boolean.class) || type.equals(Character.class) ||
type.equals(Byte.class) || type.equals(Short.class) || type.equals(Integer.class) ||
type.equals(Long.class) || type.equals(Float.class) || type.equals(Double.class) ||
(type.isArray() && isTypeExcluded(type.getComponentType())) || type.equals(GlobalTransaction.class) || Address.class.isAssignableFrom(type) ||
ReplicableCommand.class.isAssignableFrom(type) || type.equals(MarshalledValue.class);
}
public static class Externalizer extends AbstractExternalizer<MarshalledValue> {
private final StreamingMarshaller globalMarshaller;
public Externalizer(StreamingMarshaller globalMarshaller) {
this.globalMarshaller = globalMarshaller;
}
@Override
public void writeObject(ObjectOutput output, MarshalledValue mv) throws IOException {
byte[] raw = mv.getRaw();
UnsignedNumeric.writeUnsignedInt(output, raw.length);
output.write(raw);
output.writeInt(mv.hashCode());
}
@Override
public MarshalledValue readObject(ObjectInput input) throws IOException {
int length = UnsignedNumeric.readUnsignedInt(input);
byte[] raw = new byte[length];
input.readFully(raw);
int hc = input.readInt();
// A better way of sending down context information is needed in the future
StreamingMarshaller marshaller;
if (input instanceof ExtendedRiverUnmarshaller) {
StreamingMarshaller ispnMarshaller =
((ExtendedRiverUnmarshaller) input).getInfinispanMarshaller();
if (ispnMarshaller != null)
marshaller = ispnMarshaller;
else
marshaller = globalMarshaller;
} else {
marshaller = globalMarshaller;
}
return new MarshalledValue(raw, hc, marshaller);
}
@Override
public Integer getId() {
return Ids.MARSHALLED_VALUE;
}
@Override
public Set<Class<? extends MarshalledValue>> getTypeClasses() {
return Util.<Class<? extends MarshalledValue>>asSet(MarshalledValue.class);
}
}
}