// Copyright © 2012-2020 VLINGO LABS. All rights reserved. // // This Source Code Form is subject to the terms of the // Mozilla Public License, v. 2.0. If a copy of the MPL // was not distributed with this file, You can obtain // one at https://mozilla.org/MPL/2.0/. package io.vlingo.symbio.store.journal; import java.util.List; import io.vlingo.symbio.BaseEntry; import io.vlingo.symbio.State; /** * The entries and possible snapshot of a full or partial stream of a given named stream. * * @param <T> the concrete type of the stream of {@code Entry<T>}, which maybe be {@code String}, {@code byte[]}, or {@code Object} */ public class EntityStream<T> { /** * The most recent {@code State<T>} snapshot, if any. */ public final State<T> snapshot; /** * The {@code List<Entry<T>>} of the entries of the named stream, and possibly just a sub-stream. */ public final List<BaseEntry<T>> entries; /** * The String name of the stream, which is generally a global unique identity * of an associated entity/aggregate. */ public final String streamName; /** * The version of the stream, which indicates the 1-based sequence of the * last of all my entries listed herein. All entry streams start at version * 1 and end with the total number of all its entries, e.g. entries.size(). */ public final int streamVersion; /** * Construct a new Stream. * * @param streamName the {@code String} name of this stream, which is generally a global unique identity * of an associated entity/aggregate * @param streamVersion the {@code int} version of the stream * @param entries the {@code List<Entry<T>>} of all entries in the named stream or some sub-stream * @param snapshot the {@code State<T>} of a persisted state, or an empty {@code State<T>} if none */ public EntityStream(final String streamName, final int streamVersion, final List<BaseEntry<T>> entries, final State<T> snapshot) { this.streamName = streamName; this.streamVersion = streamVersion; this.entries = entries; this.snapshot = snapshot; } /** * Answers whether or not I hold a non-empty snapshot. * * @return boolean */ public boolean hasSnapshot() { return snapshot != null && !snapshot.isEmpty(); } /** * Answer my size, which is the number of entries. * @return int */ public int size() { return entries.size(); } @Override public String toString() { return "EntityStream[" + "streamName=" + streamName + " streamVersion=" + streamVersion + " entries=" + entries + " snapshot=" + snapshot + "]"; } }