com.hazelcast.internal.util.ResultSet Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020, 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.util;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.function.Predicate;
/**
*
* A result set of {@link Map.Entry} objects that can be iterated according to {@link IterationType}
*
*/
public class ResultSet extends AbstractSet {
private final List entries;
private final IterationType iterationType;
public ResultSet(List entries, IterationType iterationType) {
this.entries = (List) entries;
this.iterationType = iterationType;
}
public ResultSet() {
this(null, null);
}
@Override
public Iterator iterator() {
if (entries == null) {
return Collections.EMPTY_LIST.iterator();
}
return new ResultIterator();
}
@Override
public int size() {
if (entries == null) {
return 0;
}
return entries.size();
}
private class ResultIterator implements Iterator {
private final Iterator iterator = entries.iterator();
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public Object next() {
Map.Entry entry = iterator.next();
switch (iterationType) {
case KEY:
return entry.getKey();
case VALUE:
return entry.getValue();
case ENTRY:
return entry;
default:
throw new IllegalStateException("Unrecognized iterationType:" + iterationType);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
@Override
public boolean addAll(Collection c) {
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object o) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(Collection c) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeIf(Predicate filter) {
throw new UnsupportedOperationException();
}
public boolean retainAll(Collection coll) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
}