kafka FilteredCacheIterator 源码

kafka FilteredCacheIterator 代码

文件路径：/streams/src/main/java/org/apache/kafka/streams/state/internals/FilteredCacheIterator.java

/*
 * 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<Bytes, LRUCacheEntry> {
    private final PeekingKeyValueIterator<Bytes, LRUCacheEntry> cacheIterator;
    private final HasNextCondition hasNextCondition;
    private final PeekingKeyValueIterator<Bytes, LRUCacheEntry> wrappedIterator;

    FilteredCacheIterator(final PeekingKeyValueIterator<Bytes, LRUCacheEntry> cacheIterator,
                          final HasNextCondition hasNextCondition,
                          final CacheFunction cacheFunction) {
        this.cacheIterator = cacheIterator;
        this.hasNextCondition = hasNextCondition;
        this.wrappedIterator = new PeekingKeyValueIterator<Bytes, LRUCacheEntry>() {
            @Override
            public KeyValue<Bytes, LRUCacheEntry> 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<Bytes, LRUCacheEntry> next() {
                return cachedPair(cacheIterator.next());
            }

            private KeyValue<Bytes, LRUCacheEntry> cachedPair(final KeyValue<Bytes, LRUCacheEntry> 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<Bytes, LRUCacheEntry> next() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        return cacheIterator.next();

    }

    @Override
    public KeyValue<Bytes, LRUCacheEntry> peekNext() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        return cacheIterator.peekNext();
    }
}

相关信息

kafka 源码目录

相关文章

kafka AbstractDualSchemaRocksDBSegmentedBytesStore 源码

kafka AbstractMergedSortedCacheStoreIterator 源码

kafka AbstractRocksDBSegmentedBytesStore 源码

kafka AbstractRocksDBTimeOrderedSegmentedBytesStore 源码

kafka AbstractSegments 源码

kafka AbstractStoreBuilder 源码

kafka BatchWritingStore 源码

kafka BlockBasedTableConfigWithAccessibleCache 源码

kafka BufferKey 源码

kafka BufferValue 源码