/*
* 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.commands.read;
import org.infinispan.commands.VisitableCommand;
import org.infinispan.commands.Visitor;
import org.infinispan.container.DataContainer;
import org.infinispan.container.entries.CacheEntry;
import org.infinispan.context.InvocationContext;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
/**
* Command implementation for {@link java.util.Map#keySet()} functionality.
*
* @author Galder Zamarreño
* @author Mircea.Markus@jboss.com
* @author <a href="http://gleamynode.net/">Trustin Lee</a>
* @since 4.0
*/
public class KeySetCommand extends AbstractLocalCommand implements VisitableCommand {
private final DataContainer container;
public KeySetCommand(DataContainer container) {
this.container = container;
}
@Override
public Object acceptVisitor(InvocationContext ctx, Visitor visitor) throws Throwable {
return visitor.visitKeySetCommand(ctx, this);
}
@Override
public Set<Object> perform(InvocationContext ctx) throws Throwable {
Set<Object> objects = container.keySet(null);
if (noTxModifications(ctx)) {
return new ExpiredFilteredKeySet(objects, container);
}
return new FilteredKeySet(objects, ctx.getLookedUpEntries(), container);
}
@Override
public String toString() {
return "KeySetCommand{" +
"set=" + container.size(null) + " elements" +
'}';
}
private static class FilteredKeySet extends AbstractSet<Object> {
final Set<Object> keySet;
final Map<Object, CacheEntry> lookedUpEntries;
final DataContainer container;
FilteredKeySet(Set<Object> keySet, Map<Object, CacheEntry> lookedUpEntries, DataContainer container) {
this.keySet = keySet;
this.lookedUpEntries = lookedUpEntries;
this.container = container;
}
@Override
public int size() {
int size = keySet.size();
// First, removed any expired keys
for (Object k : keySet) {
// Given the key set, a key won't be contained if it's expired
if (!container.containsKey(k, null))
size--;
}
// Update according to keys added or removed in tx
for (CacheEntry e: lookedUpEntries.values()) {
if (e.isCreated()) {
size ++;
} else if (e.isRemoved()) {
size --;
}
}
return Math.max(size, 0);
}
@Override
public boolean contains(Object o) {
CacheEntry e = lookedUpEntries.get(o);
if (e == null || e.isRemoved()) {
return false;
} else if (e.isChanged() || e.isCreated()) {
return true;
}
return keySet.contains(o);
}
@Override
public Iterator<Object> iterator() {
return new Itr();
}
@Override
public boolean add(Object e) {
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object o) {
throw new UnsupportedOperationException();
}
@Override
public boolean addAll(Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
private class Itr implements Iterator<Object> {
private final Iterator<CacheEntry> it1 = lookedUpEntries.values().iterator();
private final Iterator<Object> it2 = keySet.iterator();
private boolean atIt1 = true;
private Object next;
Itr() {
fetchNext();
}
private void fetchNext() {
if (atIt1) {
boolean found = false;
while (it1.hasNext()) {
CacheEntry e = it1.next();
if (e.isCreated()) {
next = e.getKey();
found = true;
break;
}
}
if (!found) {
atIt1 = false;
}
}
if (!atIt1) {
boolean found = false;
while (it2.hasNext()) {
Object k = it2.next();
CacheEntry e = lookedUpEntries.get(k);
if (e == null || !e.isRemoved()) {
next = k;
found = true;
break;
}
}
if (!found) {
next = null;
}
}
}
@Override
public boolean hasNext() {
if (next == null) {
fetchNext();
}
return next != null;
}
@Override
public Object next() {
if (next == null) {
fetchNext();
}
if (next == null) {
throw new NoSuchElementException();
}
Object ret = next;
next = null;
return ret;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
}
public static class ExpiredFilteredKeySet extends AbstractSet<Object> {
final Set<Object> keySet;
final DataContainer container;
public ExpiredFilteredKeySet(Set<Object> keySet, DataContainer container) {
this.keySet = keySet;
this.container = container;
}
@Override
public boolean add(Object e) {
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object o) {
throw new UnsupportedOperationException();
}
@Override
public boolean addAll(Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
@Override
public Iterator<Object> iterator() {
return new Itr();
}
@Override
public int size() {
// Size cannot be cached because even if the set is immutable,
// over time, the expired entries could grow hence reducing the size
int s = keySet.size();
for (Object k : keySet) {
// Given the key set, a key won't be contained if it's expired
if (!container.containsKey(k, null))
s--;
}
return s;
}
private class Itr implements Iterator<Object> {
private final Iterator<Object> it = keySet.iterator();
private Object next;
private Itr() {
fetchNext();
}
private void fetchNext() {
while (it.hasNext()) {
Object k = it.next();
if (container.containsKey(k, null)) {
next = k;
break;
}
}
}
@Override
public boolean hasNext() {
if (next == null)
fetchNext();
return next != null;
}
@Override
public Object next() {
if (next == null)
fetchNext();
if (next == null)
throw new NoSuchElementException();
Object ret = next;
next = null;
return ret;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
}
}