cmccabe commented on a change in pull request #9901: URL: https://github.com/apache/kafka/pull/9901#discussion_r566481305
########## File path: metadata/src/main/java/org/apache/kafka/timeline/timeline/TimelineHashSet.java ########## @@ -0,0 +1,260 @@ +/* + * 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.timeline; + +import java.util.Collection; +import java.util.Iterator; +import java.util.Objects; +import java.util.Set; + +/** + * This is a hash set which can be snapshotted. + * + * See {@SnapshottableHashTable} for more details about the implementation. + * + * This class requires external synchronization. Null values are not supported. + * + * @param <T> The value type of the set. + */ +public class TimelineHashSet<T> + extends SnapshottableHashTable<TimelineHashSet.TimelineHashSetEntry<T>> + implements Set<T> { + static class TimelineHashSetEntry<T> + implements SnapshottableHashTable.ElementWithStartEpoch { + private final T value; + private long startEpoch; + + TimelineHashSetEntry(T value) { + this.value = value; + this.startEpoch = Long.MAX_VALUE; + } + + public T getValue() { + return value; + } + + @Override + public void setStartEpoch(long startEpoch) { + this.startEpoch = startEpoch; + } + + @Override + public long startEpoch() { + return startEpoch; + } + + @SuppressWarnings("unchecked") + @Override + public boolean equals(Object o) { + if (!(o instanceof TimelineHashSetEntry)) return false; + TimelineHashSetEntry<T> other = (TimelineHashSetEntry<T>) o; + return value.equals(other.value); + } + + @Override + public int hashCode() { + return value.hashCode(); + } + } + + public TimelineHashSet(SnapshotRegistry snapshotRegistry, int expectedSize) { + super(snapshotRegistry, expectedSize); + } + + @Override + public int size() { + return size(Long.MAX_VALUE); + } + + public int size(long epoch) { + return snapshottableSize(epoch); + } + + @Override + public boolean isEmpty() { + return isEmpty(Long.MAX_VALUE); + } + + public boolean isEmpty(long epoch) { + return snapshottableSize(epoch) == 0; + } + + @Override + public boolean contains(Object key) { + return contains(key, Long.MAX_VALUE); + } + + public boolean contains(Object object, long epoch) { + return snapshottableGet(new TimelineHashSetEntry<>(object), epoch) != null; + } + + final class ValueIterator implements Iterator<T> { + private final Iterator<TimelineHashSetEntry<T>> iter; + + ValueIterator(long epoch) { + this.iter = snapshottableIterator(epoch); + } + + @Override + public boolean hasNext() { + return iter.hasNext(); + } + + @Override + public T next() { + return iter.next().value; + } + + @Override + public void remove() { + iter.remove(); + } + } + + @Override + public Iterator<T> iterator() { + return iterator(Long.MAX_VALUE); + } + + public Iterator<T> iterator(long epoch) { + return new ValueIterator(epoch); + } + + @Override + public Object[] toArray() { + Object[] result = new Object[size()]; + Iterator<T> iter = iterator(); + int i = 0; + while (iter.hasNext()) { + result[i++] = iter.next(); + } + return result; + } + + @SuppressWarnings("unchecked") + @Override + public <R> R[] toArray(R[] a) { + int size = size(); + if (size <= a.length) { + Iterator<T> iter = iterator(); + int i = 0; + while (iter.hasNext()) { + a[i++] = (R) iter.next(); + } + while (i < a.length) { + a[i++] = null; + } + return a; + } else { + return (R[]) toArray(); + } + } + + @Override + public boolean add(T newValue) { + Objects.requireNonNull(newValue); + return snapshottableAddUnlessPresent(new TimelineHashSetEntry<>(newValue)); + } + + @Override + public boolean remove(Object value) { + return snapshottableRemove(new TimelineHashSetEntry<>(value)) != null; + } + + @Override + public boolean containsAll(Collection<?> collection) { + for (Object value : collection) { + if (!contains(value)) return false; + } + return true; + } + + @Override + public boolean addAll(Collection<? extends T> collection) { + boolean modified = false; + for (T value : collection) { + if (add(value)) { + modified = true; + } + } + return modified; + } + + @Override + public boolean retainAll(Collection<?> collection) { + Objects.requireNonNull(collection); + boolean modified = false; + Iterator<T> it = iterator(); + while (it.hasNext()) { + if (!collection.contains(it.next())) { + it.remove(); + modified = true; + } + } + return modified; + } + + @Override + public boolean removeAll(Collection<?> collection) { + Objects.requireNonNull(collection); + boolean modified = false; + Iterator<?> it = iterator(); + while (it.hasNext()) { + if (collection.contains(it.next())) { + it.remove(); + modified = true; + } + } + return modified; + } + + @Override + public void clear() { Review comment: clear just changes the current state, it doesn't affect snapshotted state ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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