org.apache.kafka.streams.state.internals.CompositeReadOnlyKeyValueStore Maven / Gradle / Ivy
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* 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.streams.errors.InvalidStateStoreException;
import org.apache.kafka.streams.state.KeyValueIterator;
import org.apache.kafka.streams.state.QueryableStoreType;
import org.apache.kafka.streams.state.ReadOnlyKeyValueStore;
import java.util.List;
import java.util.Objects;
/**
* A wrapper over the underlying {@link ReadOnlyKeyValueStore}s found in a {@link
* org.apache.kafka.streams.processor.internals.ProcessorTopology}
*
* @param key type
* @param value type
*/
public class CompositeReadOnlyKeyValueStore implements ReadOnlyKeyValueStore {
private final StateStoreProvider storeProvider;
private final QueryableStoreType> storeType;
private final String storeName;
public CompositeReadOnlyKeyValueStore(final StateStoreProvider storeProvider,
final QueryableStoreType> storeType,
final String storeName) {
this.storeProvider = storeProvider;
this.storeType = storeType;
this.storeName = storeName;
}
@Override
public V get(final K key) {
Objects.requireNonNull(key);
final List> stores = storeProvider.stores(storeName, storeType);
for (final ReadOnlyKeyValueStore store : stores) {
try {
final V result = store.get(key);
if (result != null) {
return result;
}
} catch (final InvalidStateStoreException e) {
throw new InvalidStateStoreException("State store is not available anymore and may have been migrated to another instance; please re-discover its location from the state metadata.");
}
}
return null;
}
@Override
public KeyValueIterator range(final K from, final K to) {
Objects.requireNonNull(from);
Objects.requireNonNull(to);
final NextIteratorFunction> nextIteratorFunction = new NextIteratorFunction>() {
@Override
public KeyValueIterator apply(final ReadOnlyKeyValueStore store) {
try {
return store.range(from, to);
} catch (final InvalidStateStoreException e) {
throw new InvalidStateStoreException("State store is not available anymore and may have been migrated to another instance; please re-discover its location from the state metadata.");
}
}
};
final List> stores = storeProvider.stores(storeName, storeType);
return new DelegatingPeekingKeyValueIterator<>(
storeName,
new CompositeKeyValueIterator<>(stores.iterator(), nextIteratorFunction));
}
@Override
public KeyValueIterator reverseRange(final K from, final K to) {
Objects.requireNonNull(from);
Objects.requireNonNull(to);
final NextIteratorFunction> nextIteratorFunction = new NextIteratorFunction>() {
@Override
public KeyValueIterator apply(final ReadOnlyKeyValueStore store) {
try {
return store.reverseRange(from, to);
} catch (final InvalidStateStoreException e) {
throw new InvalidStateStoreException("State store is not available anymore and may have been migrated to another instance; please re-discover its location from the state metadata.");
}
}
};
final List> stores = storeProvider.stores(storeName, storeType);
return new DelegatingPeekingKeyValueIterator<>(
storeName,
new CompositeKeyValueIterator<>(stores.iterator(), nextIteratorFunction));
}
@Override
public KeyValueIterator all() {
final NextIteratorFunction> nextIteratorFunction = new NextIteratorFunction>() {
@Override
public KeyValueIterator apply(final ReadOnlyKeyValueStore store) {
try {
return store.all();
} catch (final InvalidStateStoreException e) {
throw new InvalidStateStoreException("State store is not available anymore and may have been migrated to another instance; please re-discover its location from the state metadata.");
}
}
};
final List> stores = storeProvider.stores(storeName, storeType);
return new DelegatingPeekingKeyValueIterator<>(
storeName,
new CompositeKeyValueIterator<>(stores.iterator(), nextIteratorFunction));
}
@Override
public KeyValueIterator reverseAll() {
final NextIteratorFunction> nextIteratorFunction = new NextIteratorFunction>() {
@Override
public KeyValueIterator apply(final ReadOnlyKeyValueStore store) {
try {
return store.reverseAll();
} catch (final InvalidStateStoreException e) {
throw new InvalidStateStoreException("State store is not available anymore and may have been migrated to another instance; please re-discover its location from the state metadata.");
}
}
};
final List> stores = storeProvider.stores(storeName, storeType);
return new DelegatingPeekingKeyValueIterator<>(
storeName,
new CompositeKeyValueIterator<>(stores.iterator(), nextIteratorFunction));
}
@Override
public long approximateNumEntries() {
final List> stores = storeProvider.stores(storeName, storeType);
long total = 0;
for (final ReadOnlyKeyValueStore store : stores) {
total += store.approximateNumEntries();
if (total < 0) {
return Long.MAX_VALUE;
}
}
return total;
}
}