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Apache Geode provides a database-like consistency model, reliable transaction processing and a shared-nothing architecture to maintain very low latency performance with high concurrency processing
/*
* Licensed to the Apache Software Foundation (ASF) under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional information regarding
* copyright ownership. The ASF licenses this file to You 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 org.apache.geode.internal.cache.versions;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.TreeSet;
import org.apache.geode.internal.InternalDataSerializer;
import org.apache.geode.internal.cache.versions.RVVException.ReceivedVersionsIterator;
/**
* This subclass of RVVException is the original class that uses TreeSets to hold received versions.
* It is now only used if the exception represents a large gap.
*
*
*
*/
public class RVVExceptionT extends RVVException {
TreeSet received;
RVVExceptionT(long previousVersion, long nextVersion) {
super(previousVersion, nextVersion);
}
@Override
public void add(long receivedVersion) {
if (receivedVersion == this.previousVersion + 1) {
this.previousVersion = receivedVersion;
if (this.received != null) {
consumeReceivedVersions();
}
} else if (receivedVersion == this.nextVersion - 1) {
this.nextVersion = receivedVersion;
if (this.received != null) {
consumeReceivedVersions();
}
} else if (this.previousVersion < receivedVersion && receivedVersion < this.nextVersion) {
addReceived(receivedVersion);
}
}
@Override
protected void addReceived(long rv) {
if (this.received == null) {
this.received = new TreeSet();
}
this.received.add(rv);
}
/**
* checks to see if any of the received versions can be merged into the start/end version numbers
*/
private void consumeReceivedVersions() {
// Iterate in forward order
for (Iterator it = this.received.iterator(); it.hasNext();) {
long v = it.next();
if (v <= this.previousVersion + 1) {
// if the received version is less than the previous + 1, remove it.
it.remove();
if (v == this.previousVersion + 1) {
// if the received version is equal to previous +1, also update the previous
this.previousVersion = v;
}
} else {
// Once we reach received entries greater than the previous, stop.
break;
}
}
// Iterate in reverse order
for (Iterator it = this.received.descendingIterator(); it.hasNext();) {
long v = it.next();
if (v >= this.nextVersion - 1) {
// if the received version is greater than the next - 1, remove it.
it.remove();
if (v == this.nextVersion - 1) {
// if the received version is equal the next - 1, also update next.
this.nextVersion = v;
}
} else {
break;
}
}
}
@Override
public RVVException clone() {
RVVExceptionT clone = new RVVExceptionT(previousVersion, nextVersion);
if (this.received != null) {
clone.received = new TreeSet(this.received);
}
return clone;
}
public void writeReceived(DataOutput out) throws IOException {
int size = this.received == null ? 0 : this.received.size();
InternalDataSerializer.writeUnsignedVL(size, out);
// Write each version in the exception as a delta from the previous version
// this will likely be smaller than the absolute value, so it will
// be more likely to fit into a byte or a short.
long last = this.previousVersion;
if (this.received != null) {
for (Long version : this.received) {
long delta = version.longValue() - last;
InternalDataSerializer.writeUnsignedVL(delta, out);
last = version.longValue();
}
}
long delta = this.nextVersion - last;
InternalDataSerializer.writeUnsignedVL(delta, out);
}
@Override
public String toString() {
if (this.received != null) {
return "e(n=" + this.nextVersion + " p=" + +this.previousVersion
+ (this.received.size() == 0 ? "" : "; rs=" + this.received) + ")";
}
return "et(n=" + this.nextVersion + " p=" + this.previousVersion + "; rs=[])";
}
// @Override
// public int hashCode() {
// final int prime = 31;
// int result = 1;
// result = prime * result + (int) (nextVersion ^ (nextVersion >>> 32));
// result = prime * result
// + (int) (previousVersion ^ (previousVersion >>> 32));
// result = prime * result + ((this.received == null) ? 0 : this.received.hashCode());
// return result;
// }
/**
* For test purposes only. This isn't quite accurate, because I think two RVVs that have
* effectively same exceptions may represent the exceptions differently. This method is testing
* for an exact match of exception format.
*/
@Override
public boolean sameAs(RVVException ex) {
if (!super.sameAs(ex)) {
return false;
}
RVVExceptionT other = (RVVExceptionT) ex;
if (this.received == null) {
if (other.received != null && !other.received.isEmpty()) {
return false;
}
} else if (other.received == null || !this.received.equals(other.received)) {
return false;
}
return true;
}
protected boolean sameAs(RVVExceptionB ex) {
if (!super.sameAs(ex)) {
return false;
}
for (ReceivedVersionsIterator it = receivedVersionsIterator(); it.hasNext();) {
if (!ex.contains(it.next())) {
return false;
}
}
for (ReceivedVersionsIterator it = ex.receivedVersionsIterator(); it.hasNext();) {
if (!contains(it.next())) {
return false;
}
}
return true;
}
/** has the given version been recorded as having been received? */
public boolean contains(long version) {
if (version <= this.previousVersion) {
return false;
}
return (this.received != null && (this.received.contains(version)));
}
/** return false if any revisions have been recorded in the range of this exception */
public boolean isEmpty() {
return (this.received == null || this.received.isEmpty());
}
public ReceivedVersionsIterator receivedVersionsIterator() {
ReceivedVersionsIteratorT result = new ReceivedVersionsIteratorT();
result.initForForwardIteration();
return result;
}
public long getHighestReceivedVersion() {
if (received == null || received.isEmpty()) {
return previousVersion;
} else {
return received.last();
}
}
@Override
public boolean shouldChangeForm() {
// If the received set size * 512 as big as the gap in versions, switch
// to using bitset instead because that will use less memory.
// A bit set using 1 bit for each *possible* entry
// A treeset uses approximately 64 bytes for each *actual* entry
return this.received != null
&& this.received.size() * 512 > this.nextVersion - this.previousVersion;
}
@Override
public RVVException changeForm() {
// Convert the exception to a bitset exception
RVVExceptionB ex = new RVVExceptionB(previousVersion, nextVersion);
for (ReceivedVersionsIterator it = this.receivedVersionsIterator(); it.hasNext();) {
long next = it.next();
ex.add(next);
}
return ex;
}
/** it's a shame that BitSet has no iterator */
protected class ReceivedVersionsIteratorT extends ReceivedVersionsIterator {
boolean noIterator;
Iterator treeSetIterator;
void initForForwardIteration() {
if (received == null) {
this.noIterator = true;
} else {
this.treeSetIterator = received.iterator();
}
}
boolean hasNext() {
return !noIterator && this.treeSetIterator.hasNext();
}
long next() {
if (!noIterator) {
return this.treeSetIterator.next().longValue();
}
throw new NoSuchElementException("no more elements");
}
void remove() {
if (!noIterator) {
this.treeSetIterator.remove();
}
}
}
}