/*
* Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.internal.cluster.impl;
import com.hazelcast.core.Member;
import com.hazelcast.core.MemberSelector;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
/**
* An immutable collection that applies all the {@link com.hazelcast.core.MemberSelector} instances to
* its internal {@link com.hazelcast.core.Member} collection. It reflects changes in the internal collection.
* Mutating methods throw {@link java.lang.UnsupportedOperationException}
* It is mainly used for querying a member list.
* @param <M> A subclass of {@link com.hazelcast.core.Member} interface
*/
public final class MemberSelectingCollection<M extends Member> implements Collection<M> {
private final Collection<M> members;
private final MemberSelector selector;
public MemberSelectingCollection(Collection<M> members, MemberSelector selector) {
this.members = members;
this.selector = selector;
}
@Override
public int size() {
int size = 0;
for (M member : members) {
if (selector.select(member)) {
size++;
}
}
return size;
}
@Override
public boolean isEmpty() {
return !iterator().hasNext();
}
@Override
public boolean contains(Object o) {
for (M member : members) {
if (selector.select(member) && o.equals(member)) {
return true;
}
}
return false;
}
@Override
public Iterator<M> iterator() {
return new MemberSelectingIterator();
}
@Override
public Object[] toArray() {
List<Object> result = new ArrayList<Object>();
for (M member : members) {
if (selector.select(member)) {
result.add(member);
}
}
return result.toArray(new Object[result.size()]);
}
@Override
public <T> T[] toArray(T[] a) {
List<Object> result = new ArrayList<Object>();
for (M member : members) {
if (selector.select(member)) {
result.add(member);
}
}
if (a.length != result.size()) {
a = (T[]) Array.newInstance(a.getClass().getComponentType(), result.size());
}
for (int i = 0; i < a.length; i++) {
a[i] = (T) result.get(i);
}
return a;
}
@Override
public boolean add(M member) {
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object o) {
throw new UnsupportedOperationException();
}
@Override
public boolean containsAll(Collection<?> c) {
for (Object o : c) {
if (!contains(o)) {
return false;
}
}
return true;
}
@Override
public boolean addAll(Collection<? extends M> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
class MemberSelectingIterator
implements Iterator<M> {
private final Iterator<M> iterator = MemberSelectingCollection.this.members.iterator();
private M member;
@Override
public boolean hasNext() {
while (this.member == null && iterator.hasNext()) {
M nextMember = iterator.next();
if (selector.select(nextMember)) {
this.member = nextMember;
}
}
return member != null;
}
@Override
public M next() {
M nextMember;
if (member != null || hasNext()) {
nextMember = member;
member = null;
} else {
throw new NoSuchElementException();
}
return nextMember;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
}