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https://github.com/OpenHFT/Chronicle-Map.git
synced 2021-09-13 01:26:12 +00:00
HCOLL-155 added two of peters tests and them implemented the code accordingly - the test are net.openhft.chronicle.map.ChronicleMapTest#testOffheapAcquireUsingLocked and net.openhft.chronicle.map.ChronicleMapTest#testOnheapAcquireUsingLocked
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@@ -45,8 +45,7 @@ import static net.openhft.lang.MemoryUnit.*;
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import static net.openhft.lang.collection.DirectBitSet.NOT_FOUND;
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/**
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* <h2>A Replicating Multi Master HashMap</h2>
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* <p>Each remote hash map, mirrors its changes over to
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* <h2>A Replicating Multi Master HashMap</h2> <p>Each remote hash map, mirrors its changes over to
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* another remote hash map, neither hash map is considered the master store of data, each hash map
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* uses timestamps to reconcile changes. We refer to an instance of a remote hash-map as a node. A
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* node will be connected to any number of other nodes, for the first implementation the maximum
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@@ -58,11 +57,9 @@ import static net.openhft.lang.collection.DirectBitSet.NOT_FOUND;
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* nature of this multi master implementation, this return value will only be the old value on the
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* nodes local data store. In other words the nodes are only concurrent locally. Its worth realising
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* that another node performing exactly the same operation may return a different value. However
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* reconciliation will ensure the maps themselves become eventually consistent.
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* </p>
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* <h2>Reconciliation </h2>
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* <p>If two ( or more nodes ) were to receive a change to their maps for the
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* same key but different values, say by a user of the maps, calling the put(key, value). Then,
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* reconciliation will ensure the maps themselves become eventually consistent. </p>
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* <h2>Reconciliation </h2> <p>If two ( or more nodes ) were to receive a change to their maps for
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* the same key but different values, say by a user of the maps, calling the put(key, value). Then,
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* initially each node will update its local store and each local store will hold a different value,
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* but the aim of multi master replication is to provide eventual consistency across the nodes. So,
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* with multi master when ever a node is changed it will notify the other nodes of its change. We
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@@ -71,8 +68,7 @@ import static net.openhft.lang.collection.DirectBitSet.NOT_FOUND;
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* and value. Eventual consistency is achieved by looking at the timestamp from the remote node, if
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* for a given key, the remote nodes timestamp is newer than the local nodes timestamp, then the
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* event from the remote node will be applied to the local node, otherwise the event will be
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* ignored. </p>
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* <p>However there is an edge case that we have to concern ourselves with, If two
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* ignored. </p> <p>However there is an edge case that we have to concern ourselves with, If two
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* nodes update their map at the same time with different values, we have to deterministically
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* resolve which update wins, because of eventual consistency both nodes should end up locally
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* holding the same data. Although it is rare two remote nodes could receive an update to their maps
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@@ -81,8 +77,7 @@ import static net.openhft.lang.collection.DirectBitSet.NOT_FOUND;
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* newest timestamp should win, but in this example both timestamps are the same, and the decision
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* made to one node should be identical to the decision made to the other. We resolve this simple
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* dilemma by using a node identifier, each node will have a unique identifier, the update from the
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* node with the smallest identifier wins.
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* </p>
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* node with the smallest identifier wins. </p>
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*
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* @param <K> the entries key type
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* @param <V> the entries value type
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@@ -260,19 +255,41 @@ class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
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return (Segment) segments[segmentNum];
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}
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@Override
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V lookupUsing(K key, V value, boolean create) {
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LockedEntry<K, V> acquireUsing(K key, V value, LockType lockTypeType) {
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checkKey(key);
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ThreadLocalCopies copies = keyInteropProvider.getCopies(null);
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KI keyWriter = keyInteropProvider.get(copies, originalKeyInterop);
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KI keyInterop = keyInteropProvider.get(copies, originalKeyInterop);
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copies = metaKeyInteropProvider.getCopies(copies);
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MKI metaKeyWriter =
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metaKeyInteropProvider.get(copies, originalMetaKeyInterop, keyWriter, key);
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long hash = metaKeyWriter.hash(keyWriter, key);
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MKI metaKeyInterop =
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metaKeyInteropProvider.get(copies, originalMetaKeyInterop, keyInterop, key);
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long hash = metaKeyInterop.hash(keyInterop, key);
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int segmentNum = getSegment(hash);
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long segmentHash = segmentHash(hash);
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return segment(segmentNum).acquire(copies, metaKeyWriter, keyWriter, key, value,
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segmentHash, create, create ? timeProvider.currentTimeMillis() : 0L);
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Segment segment = segment(segmentNum);
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MutableLockedEntry<K, V, MKI, KI> lock = (lockTypeType == LockType.WRITE_LOCK)
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? segment.writeLock()
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: segment.readLock();
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V v = segment.acquireWithoutLock(copies, metaKeyInterop, keyInterop, key, value,
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segmentHash, lockTypeType == LockType.WRITE_LOCK,
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(lockTypeType == LockType.WRITE_LOCK) ? timeProvider.currentTimeMillis() : 0L);
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// we want to call put on heap objects that don't currently exist in the map
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if (v == null && !isNativeValueClass && lockTypeType == LockType.WRITE_LOCK) {
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lock.copies = copies;
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lock.metaKeyInterop = metaKeyInterop;
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lock.keyInterop = keyInterop;
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lock.segmentHash = segmentHash;
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v = value;
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}
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lock.value(v);
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lock.key(key);
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return lock;
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}
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@Override
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@@ -611,50 +628,38 @@ class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
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return result;
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}
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V acquireWithoutLock(ThreadLocalCopies copies, MKI metaKeyInterop, KI keyInterop, K key, V usingValue,
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long hash2, boolean create, long timestamp) {
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/**
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* @see VanillaChronicleMap.Segment#acquire
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*/
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V acquire(ThreadLocalCopies copies, MKI metaKeyInterop, KI keyInterop,
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K key, V usingValue, long hash2, boolean create, long timestamp) {
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if (create)
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writeLock();
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else
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readLock();
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try {
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long keySize = metaKeyInterop.size(keyInterop, key);
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MultiStoreBytes entry = acquireTmpBytes();
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long offset = searchKey(keyInterop, metaKeyInterop, key, keySize, hash2, entry,
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hashLookupLiveOnly);
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if (offset >= 0L) {
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return onKeyPresentOnAcquire(copies, key, usingValue, offset, entry);
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long keySize = metaKeyInterop.size(keyInterop, key);
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MultiStoreBytes entry = acquireTmpBytes();
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long offset = searchKey(keyInterop, metaKeyInterop, key, keySize, hash2, entry,
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hashLookupLiveOnly);
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if (offset >= 0L) {
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return onKeyPresentOnAcquire(copies, key, usingValue, offset, entry);
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} else {
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if (!create)
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return null;
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if (defaultValueProvider != null) {
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V defaultValue = defaultValueProvider.get(key);
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copies = valueWriterProvider.getCopies(copies);
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VW valueWriter = valueWriterProvider.get(copies, originalValueWriter);
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copies = metaValueWriterProvider.getCopies(copies);
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MetaBytesWriter<V, VW> metaValueWriter = metaValueWriterProvider.get(
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copies, originalMetaValueWriter, valueWriter, defaultValue);
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offset = putEntry(metaKeyInterop, keyInterop, key, keySize, hash2,
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localIdentifier, timestamp, hashLookupLiveOnly,
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metaValueWriter, valueWriter, defaultValue);
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} else {
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if (!create)
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return null;
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if (defaultValueProvider != null) {
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V defaultValue = defaultValueProvider.get(key);
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copies = valueWriterProvider.getCopies(copies);
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VW valueWriter = valueWriterProvider.get(copies, originalValueWriter);
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copies = metaValueWriterProvider.getCopies(copies);
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MetaBytesWriter<V, VW> metaValueWriter = metaValueWriterProvider.get(
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copies, originalMetaValueWriter, valueWriter, defaultValue);
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offset = putEntry(metaKeyInterop, keyInterop, key, keySize, hash2,
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localIdentifier, timestamp, hashLookupLiveOnly,
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metaValueWriter, valueWriter, defaultValue);
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} else {
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offset = putEntry(metaKeyInterop, keyInterop, key, keySize, hash2,
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localIdentifier, timestamp, hashLookupLiveOnly,
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prepareValueBytesAsWriter, null, key);
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}
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return onKeyAbsentOnAcquire(copies, key, keySize, usingValue, offset);
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offset = putEntry(metaKeyInterop, keyInterop, key, keySize, hash2,
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localIdentifier, timestamp, hashLookupLiveOnly,
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prepareValueBytesAsWriter, null, key);
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}
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} finally {
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if (create)
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writeUnlock();
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else
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readUnlock();
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return onKeyAbsentOnAcquire(copies, key, keySize, usingValue, offset);
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}
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}
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@Override
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@@ -869,8 +874,7 @@ class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
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/**
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* Used only with replication, its sometimes possible to receive an old ( or stale update )
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* from a remote map. This method is used to determine if we should ignore such updates.
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* <p>We can reject put() and removes() when comparing times stamps with remote
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* systems
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* <p>We can reject put() and removes() when comparing times stamps with remote systems
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*
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* @param entry the maps entry
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* @param timestamp the time the entry was created or updated
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@@ -1321,8 +1325,8 @@ class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
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}
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/**
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* Always throws {@code NotSerializableException} since instances of this class are not intended to be
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* serializable.
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* Always throws {@code NotSerializableException} since instances of this class are not
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* intended to be serializable.
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*/
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private void writeObject(ObjectOutputStream out) throws IOException {
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throw new NotSerializableException(getClass().getCanonicalName());
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@@ -1341,18 +1345,15 @@ class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
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}
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/**
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* <p>Once a change occurs to a map, map replication requires that these changes are picked up by
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* another thread, this class provides an iterator like interface to poll for such changes.
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* </p>
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* <p>In most cases the thread that adds data to the node is unlikely to be the same thread that
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* replicates the data over to the other nodes, so data will have to be marshaled between the
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* main thread storing data to the map, and the thread running the replication.
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* </p>
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* <p>One way to perform this marshalling, would be to pipe the data into a queue. However, This class
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* <p>Once a change occurs to a map, map replication requires that these changes are picked up
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* by another thread, this class provides an iterator like interface to poll for such changes.
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* </p> <p>In most cases the thread that adds data to the node is unlikely to be the same thread
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* that replicates the data over to the other nodes, so data will have to be marshaled between
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* the main thread storing data to the map, and the thread running the replication. </p> <p>One
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* way to perform this marshalling, would be to pipe the data into a queue. However, This class
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* takes another approach. It uses a bit set, and marks bits which correspond to the indexes of
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* the entries that have changed. It then provides an iterator like interface to poll for such
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* changes.
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* </p>
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* changes. </p>
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*
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* @author Rob Austin.
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*/
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