refactor: extract some Shadowgraph related classes to gossip module

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/gossip/shadowgraph/InsertableStatus.java → platform-sdk/consensus-gossip-impl/src/main/java/com/hedera/service/gossip/impl/shadowgraph/InsertableStatus.java

@@ -14,10 +14,10 @@
  * limitations under the License.
  */
 
-package com.swirlds.platform.gossip.shadowgraph;
+package com.hedera.service.gossip.impl.shadowgraph;
 
 /**
- * A status representing the ability of the {@link Shadowgraph} to insert an event.
+ * A status representing the ability of the {Shadowgraph} to insert an event.
  */
 public enum InsertableStatus {
     /** The event can be inserted into the shadow graph. */

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/gossip/shadowgraph/ShadowgraphInsertionException.java → platform-sdk/consensus-gossip-impl/src/main/java/com/hedera/service/gossip/impl/shadowgraph/ShadowgraphInsertionException.java

@@ -14,10 +14,10 @@
  * limitations under the License.
  */
 
-package com.swirlds.platform.gossip.shadowgraph;
+package com.hedera.service.gossip.impl.shadowgraph;
 
 /**
- * An exception thrown by {@link Shadowgraph} when an event cannot be added to the shadow graph.
+ * An exception thrown by {Shadowgraph} when an event cannot be added to the shadow graph.
  */
 public class ShadowgraphInsertionException extends RuntimeException {
 

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/gossip/shadowgraph/ShadowgraphReservation.java → platform-sdk/consensus-gossip-impl/src/main/java/com/hedera/service/gossip/impl/shadowgraph/ShadowgraphReservation.java

@@ -14,14 +14,14 @@
  * limitations under the License.
  */
 
-package com.swirlds.platform.gossip.shadowgraph;
+package com.hedera.service.gossip.impl.shadowgraph;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * Represents zero or more reservations for an ancient indicator (i.e. a generation or a birth round, depending on
- * current {@link com.swirlds.platform.event.AncientMode andient mode}). It is used to determine when it is safe to
- * expire events in a given ancient indicator. Reservations are made by gossip threads inside {@link Shadowgraph}.
+ * current {ancient mode}). It is used to determine when it is safe to
+ * expire events in a given ancient indicator. Reservations are made by gossip threads inside {Shadowgraph}.
  * Ancient indicators that have at least one reservation may not have any of its events expired.
  */
 public final class ShadowgraphReservation implements AutoCloseable {

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/gossip/shadowgraph/SyncResult.java → platform-sdk/consensus-gossip-impl/src/main/java/com/hedera/service/gossip/impl/shadowgraph/SyncResult.java

@@ -14,12 +14,12 @@
  * limitations under the License.
  */
 
-package com.swirlds.platform.gossip.shadowgraph;
+package com.hedera.service.gossip.impl.shadowgraph;
 
 import com.swirlds.common.platform.NodeId;
 
 /**
- * Information about a successful sync that just occurred
+ * Information about a successful sync that just occurred.
  */
 public class SyncResult {
     private final boolean caller;
@@ -28,14 +28,16 @@ public class SyncResult {
     private final int eventsWritten;
 
     /**
+     * Constructs a new SyncResult.
+     *
      * @param caller
-     * 		true if this node initiated the sync, false otherwise
+     *      true if this node initiated the sync, false otherwise
      * @param otherId
-     * 		the ID of the node we synced with
+     *      the ID of the node we synced with
      * @param eventsRead
-     * 		the number of events read during the sync
+     *      the number of events read during the sync
      * @param eventsWritten
-     * 		the number of events written during the sync
+     *      the number of events written during the sync
      */
     public SyncResult(final boolean caller, final NodeId otherId, final int eventsRead, final int eventsWritten) {
         this.caller = caller;
@@ -45,27 +47,35 @@ public SyncResult(final boolean caller, final NodeId otherId, final int eventsRe
     }
 
     /**
+     * Returns whether this node initiated the sync.
+     *
      * @return true if this node initiated the sync, false otherwise
      */
     public boolean isCaller() {
         return caller;
     }
 
     /**
+     * Returns the ID of the node synced with.
+     *
      * @return the ID of the node we synced with
      */
     public NodeId getOtherId() {
         return otherId;
     }
 
     /**
+     * Returns the number of events read during the sync.
+     *
      * @return the number of events read during the sync
      */
     public int getEventsRead() {
         return eventsRead;
     }
 
     /**
+     * Returns the number of events written during the sync.
+     *
      * @return the number of events written during the sync
      */
     public int getEventsWritten() {

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/gossip/shadowgraph/SyncTiming.java → platform-sdk/consensus-gossip-impl/src/main/java/com/hedera/service/gossip/impl/shadowgraph/SyncTiming.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.swirlds.platform.gossip.shadowgraph;
+package com.hedera.service.gossip.impl.shadowgraph;
 
 /**
  * A type to record the points for gossip steps. At the end of a gossip session,
@@ -23,58 +23,58 @@
  */
 public class SyncTiming {
     /**
-     * number of time points to record = {number of time intervals} + 1
+     * Number of time points to record = {number of time intervals} + 1.
      */
     private static final int NUM_TIME_POINTS = 6;
 
     /**
-     * JVM time points, in nanoseconds
+     * JVM time points, in nanoseconds.
      */
-    private final long[] t = new long[NUM_TIME_POINTS];
+    private final long[] timePoints = new long[NUM_TIME_POINTS];
 
     /**
-     * Set the 0th time point
+     * Set the 0th time point.
      */
     public void start() {
-        t[0] = now();
+        timePoints[0] = now();
     }
 
     /**
-     * Record the ith time point
+     * Record the ith time point.
      *
-     * @param i
-     * 		the ith time point to record
+     * @param index
+     *      the ith time point to record
      */
-    public void setTimePoint(final int i) {
-        t[i] = now();
+    public void setTimePoint(final int index) {
+        timePoints[index] = now();
     }
 
     /**
-     * Get the ith time point
+     * Get the ith time point.
      *
-     * @param i
-     * 		the index of the time point
+     * @param index
+     *      the index of the time point
      * @return the ith recorded time point
      */
-    public long getTimePoint(final int i) {
-        return t[i];
+    public long getTimePoint(final int index) {
+        return timePoints[index];
     }
 
     /**
-     * Get the difference between two time points
+     * Get the difference between two time points.
      *
      * @param end
-     * 		the ending point
+     *      the ending point
      * @param start
-     * 		the starting point
+     *      the starting point
      * @return the difference
      */
     public long getPointDiff(final int end, final int start) {
-        return t[end] - t[start];
+        return timePoints[end] - timePoints[start];
     }
 
     /**
-     * Get the current system time value in ns
+     * Get the current system time value in ns.
      *
      * @return current time in ns
      */

platform-sdk/consensus-gossip-impl/src/main/java/module-info.java

@@ -1,5 +1,6 @@
 module com.hedera.consensus.gossip.impl {
     exports com.hedera.service.gossip.impl;
+    exports com.hedera.service.gossip.impl.shadowgraph;
 
     requires transitive com.swirlds.common;
     requires transitive com.hedera.service.gossip;

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/gossip/shadowgraph/ReservedEventWindow.java

@@ -16,6 +16,7 @@
 
 package com.swirlds.platform.gossip.shadowgraph;
 
+import com.hedera.service.gossip.impl.shadowgraph.ShadowgraphReservation;
 import com.swirlds.platform.consensus.EventWindow;
 import edu.umd.cs.findbugs.annotations.NonNull;
 import java.util.Objects;

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/gossip/shadowgraph/Shadowgraph.java

@@ -21,6 +21,9 @@
 import static com.swirlds.logging.legacy.LogMarker.SYNC_INFO;
 
 import com.hedera.service.gossip.IntakeEventCounter;
+import com.hedera.service.gossip.impl.shadowgraph.InsertableStatus;
+import com.hedera.service.gossip.impl.shadowgraph.ShadowgraphInsertionException;
+import com.hedera.service.gossip.impl.shadowgraph.ShadowgraphReservation;
 import com.swirlds.common.AddressBook;
 import com.swirlds.common.context.PlatformContext;
 import com.swirlds.common.crypto.Hash;

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/gossip/shadowgraph/ShadowgraphSynchronizer.java

@@ -29,6 +29,8 @@
 
 import com.hedera.service.gossip.FallenBehindManager;
 import com.hedera.service.gossip.IntakeEventCounter;
+import com.hedera.service.gossip.impl.shadowgraph.SyncResult;
+import com.hedera.service.gossip.impl.shadowgraph.SyncTiming;
 import com.swirlds.base.time.Time;
 import com.swirlds.common.context.PlatformContext;
 import com.swirlds.common.platform.NodeId;

platform-sdk/swirlds-platform-core/src/main/java/com/swirlds/platform/metrics/SyncMetrics.java

@@ -22,14 +22,14 @@
 import static com.swirlds.metrics.api.Metrics.INTERNAL_CATEGORY;
 import static com.swirlds.metrics.api.Metrics.PLATFORM_CATEGORY;
 
+import com.hedera.service.gossip.impl.shadowgraph.SyncResult;
+import com.hedera.service.gossip.impl.shadowgraph.SyncTiming;
 import com.swirlds.base.units.UnitConstants;
 import com.swirlds.common.metrics.RunningAverageMetric;
 import com.swirlds.common.metrics.extensions.CountPerSecond;
 import com.swirlds.metrics.api.Metrics;
 import com.swirlds.platform.consensus.EventWindow;
 import com.swirlds.platform.gossip.shadowgraph.ShadowgraphSynchronizer;
-import com.swirlds.platform.gossip.shadowgraph.SyncResult;
-import com.swirlds.platform.gossip.shadowgraph.SyncTiming;
 import com.swirlds.platform.network.Connection;
 import com.swirlds.platform.stats.AverageAndMax;
 import com.swirlds.platform.stats.AverageAndMaxTimeStat;

platform-sdk/swirlds-unit-tests/core/swirlds-platform-test/src/test/java/com/swirlds/platform/test/sync/ShadowGraphTest.java

@@ -29,6 +29,7 @@
 import static org.mockito.Mockito.mock;
 
 import com.hedera.service.gossip.impl.NoOpIntakeEventCounter;
+import com.hedera.service.gossip.impl.shadowgraph.ShadowgraphInsertionException;
 import com.swirlds.common.AddressBook;
 import com.swirlds.common.context.PlatformContext;
 import com.swirlds.common.crypto.Hash;
@@ -39,7 +40,6 @@
 import com.swirlds.platform.gossip.shadowgraph.ReservedEventWindow;
 import com.swirlds.platform.gossip.shadowgraph.ShadowEvent;
 import com.swirlds.platform.gossip.shadowgraph.Shadowgraph;
-import com.swirlds.platform.gossip.shadowgraph.ShadowgraphInsertionException;
 import com.swirlds.platform.internal.EventImpl;
 import com.swirlds.platform.system.events.EventDescriptorWrapper;
 import com.swirlds.platform.test.event.emitter.EventEmitterFactory;

platform-sdk/swirlds-unit-tests/core/swirlds-platform-test/src/test/java/com/swirlds/platform/test/sync/ShadowgraphByBirthRoundTests.java

@@ -29,6 +29,7 @@
 import static org.mockito.Mockito.mock;
 
 import com.hedera.service.gossip.impl.NoOpIntakeEventCounter;
+import com.hedera.service.gossip.impl.shadowgraph.ShadowgraphInsertionException;
 import com.swirlds.common.AddressBook;
 import com.swirlds.common.context.PlatformContext;
 import com.swirlds.common.crypto.Hash;
@@ -42,7 +43,6 @@
 import com.swirlds.platform.gossip.shadowgraph.ReservedEventWindow;
 import com.swirlds.platform.gossip.shadowgraph.ShadowEvent;
 import com.swirlds.platform.gossip.shadowgraph.Shadowgraph;
-import com.swirlds.platform.gossip.shadowgraph.ShadowgraphInsertionException;
 import com.swirlds.platform.internal.EventImpl;
 import com.swirlds.platform.system.events.EventDescriptorWrapper;
 import com.swirlds.platform.test.event.emitter.EventEmitterFactory;

platform-sdk/swirlds-unit-tests/core/swirlds-platform-test/src/test/java/com/swirlds/platform/test/sync/SyncNode.java

@@ -22,6 +22,7 @@
 
 import com.hedera.service.gossip.IntakeEventCounter;
 import com.hedera.service.gossip.impl.NoOpIntakeEventCounter;
+import com.hedera.service.gossip.impl.shadowgraph.ShadowgraphInsertionException;
 import com.swirlds.common.AddressBook;
 import com.swirlds.common.context.PlatformContext;
 import com.swirlds.common.platform.NodeId;
@@ -37,7 +38,6 @@
 import com.swirlds.platform.event.hashing.EventHasher;
 import com.swirlds.platform.eventhandling.EventConfig_;
 import com.swirlds.platform.gossip.shadowgraph.Shadowgraph;
-import com.swirlds.platform.gossip.shadowgraph.ShadowgraphInsertionException;
 import com.swirlds.platform.gossip.shadowgraph.ShadowgraphSynchronizer;
 import com.swirlds.platform.gossip.sync.config.SyncConfig_;
 import com.swirlds.platform.internal.EventImpl;