org.apache.kafka.streams.state.internals.FilteredCacheIterator Maven / Gradle / Ivy
/*
* 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.kafka.streams.state.internals;
import org.apache.kafka.common.utils.Bytes;
import org.apache.kafka.streams.KeyValue;
import java.util.NoSuchElementException;
class FilteredCacheIterator implements PeekingKeyValueIterator {
private final PeekingKeyValueIterator cacheIterator;
private final HasNextCondition hasNextCondition;
private final PeekingKeyValueIterator wrappedIterator;
FilteredCacheIterator(final PeekingKeyValueIterator cacheIterator,
final HasNextCondition hasNextCondition,
final CacheFunction cacheFunction) {
this.cacheIterator = cacheIterator;
this.hasNextCondition = hasNextCondition;
this.wrappedIterator = new PeekingKeyValueIterator() {
@Override
public KeyValue peekNext() {
return cachedPair(cacheIterator.peekNext());
}
@Override
public void close() {
cacheIterator.close();
}
@Override
public Bytes peekNextKey() {
return cacheFunction.key(cacheIterator.peekNextKey());
}
@Override
public boolean hasNext() {
return cacheIterator.hasNext();
}
@Override
public KeyValue next() {
return cachedPair(cacheIterator.next());
}
private KeyValue cachedPair(final KeyValue next) {
return KeyValue.pair(cacheFunction.key(next.key), next.value);
}
};
}
@Override
public void close() {
// no-op
}
@Override
public Bytes peekNextKey() {
if (!hasNext()) {
throw new NoSuchElementException();
}
return cacheIterator.peekNextKey();
}
@Override
public boolean hasNext() {
return hasNextCondition.hasNext(wrappedIterator);
}
@Override
public KeyValue next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
return cacheIterator.next();
}
@Override
public KeyValue peekNext() {
if (!hasNext()) {
throw new NoSuchElementException();
}
return cacheIterator.peekNext();
}
}