IGNITE-24963 Post review fixes 6

Author: ascherbakoff

modules/transactions/src/main/java/org/apache/ignite/internal/tx/DeadlockPreventionPolicy.java

@@ -42,7 +42,7 @@ public interface DeadlockPreventionPolicy {
      *
      * @return Transaction id comparator.
      */
-    @Nullable default Comparator<UUID> txIdComparator() {
+    default Comparator<UUID> txIdComparator() {
         return TX_ID_PRIORITY_COMPARATOR;
     }
 
@@ -51,6 +51,7 @@ public interface DeadlockPreventionPolicy {
      * of this transaction with another one on certain key. If a policy allows deadlock prevention,
      * then this timeout is applied only to a waiting transaction. If this method returns {@code 0} this means that
      * the lock attempt is aborted instantly (timeout is zero). If lesser that {@code 0}, it means that the wait time is infinite.
+     * TODO IGNITE-28507 make configurable.
      *
      * @return Timeout, in milliseconds.
      */

modules/transactions/src/main/java/org/apache/ignite/internal/tx/TransactionIds.java

@@ -94,4 +94,28 @@ public static int hash(UUID txId, int divisor) {
     private static int spread(int h) {
         return (h ^ (h >>> 16)) & 0x7fffffff;
     }
+
+    /**
+     * Compares transaction IDs based on their associated priorities and the IDs themselves.
+     * The IDs with higher priorities are sorted first.
+     * If the priorities are equal, the IDs are sorted by their natural order, based on tx begin timestamp,
+     * which implies older transactions having more priority than younger.
+     *
+     * @param id1 id1.
+     * @param id2 id2.
+     *
+     * @return The result.
+     */
+    public static int compare(UUID id1, UUID id2) {
+        TxPriority priority1 = priority(id1);
+        TxPriority priority2 = priority(id2);
+
+        int priorityComparison = priority1.compareTo(priority2);
+
+        if (priorityComparison == 0) {
+            return id1.compareTo(id2);
+        } else {
+            return priorityComparison * -1; // Reverse order.
+        }
+    }
 }

modules/transactions/src/main/java/org/apache/ignite/internal/tx/impl/HeapLockManager.java

@@ -625,7 +625,7 @@ public CompletableFuture<Lock> acquire(UUID txId, LockMode lockMode) {
 
                             // Prevent deadlocks by allowing only younger transactions to wait.
                             for (Lock lock : ixlockOwners.values()) {
-                                if (deadlockPreventionPolicy.txIdComparator().compare(txId, lock.txId()) < 0) {
+                                if (TransactionIds.compare(txId, lock.txId()) < 0) {
                                     return notifyAndFail(txId, lock.txId(), lockMode, lock.lockMode());
                                 }
                             }

modules/transactions/src/main/java/org/apache/ignite/internal/tx/impl/ReversedWaitDieDeadlockPreventionPolicy.java

@@ -18,6 +18,7 @@
 package org.apache.ignite.internal.tx.impl;
 
 import org.apache.ignite.internal.tx.DeadlockPreventionPolicy;
+import org.apache.ignite.internal.tx.TransactionIds;
 import org.apache.ignite.internal.tx.Waiter;
 
 /**
@@ -27,7 +28,7 @@
 public class ReversedWaitDieDeadlockPreventionPolicy implements DeadlockPreventionPolicy {
     @Override
     public Waiter allowWait(Waiter waiter, Waiter owner) {
-        int res = txIdComparator().compare(waiter.txId(), owner.txId());
+        int res = TransactionIds.compare(waiter.txId(), owner.txId());
         assert res != 0;
 
         // Waiter is allowed to wait for owner if it's younger.

modules/transactions/src/main/java/org/apache/ignite/internal/tx/impl/TxIdPriorityComparator.java

@@ -20,26 +20,14 @@
 import java.util.Comparator;
 import java.util.UUID;
 import org.apache.ignite.internal.tx.TransactionIds;
-import org.apache.ignite.internal.tx.TxPriority;
 
 /**
  * Comparator for transaction IDs based on their associated priorities and the IDs themselves. The IDs with higher priorities are sorted
  * first. If the priorities are equal, the IDs are sorted by their natural order.
  */
 public class TxIdPriorityComparator implements Comparator<UUID> {
-    private static final Comparator<TxPriority> TX_PRIORITY_COMPARATOR = TxPriority::compareTo;
-
     @Override
     public int compare(UUID o1, UUID o2) {
-        TxPriority priority1 = TransactionIds.priority(o1);
-        TxPriority priority2 = TransactionIds.priority(o2);
-
-        int priorityComparison = TX_PRIORITY_COMPARATOR.compare(priority1, priority2);
-
-        if (priorityComparison == 0) {
-            return o1.compareTo(o2);
-        } else {
-            return priorityComparison * -1; // Reverse order.
-        }
+        return TransactionIds.compare(o1, o2);
     }
 }

modules/transactions/src/main/java/org/apache/ignite/internal/tx/impl/WaitDieDeadlockPreventionPolicy.java

@@ -18,6 +18,7 @@
 package org.apache.ignite.internal.tx.impl;
 
 import org.apache.ignite.internal.tx.DeadlockPreventionPolicy;
+import org.apache.ignite.internal.tx.TransactionIds;
 import org.apache.ignite.internal.tx.Waiter;
 
 /**
@@ -39,7 +40,7 @@ public long waitTimeout() {
 
     @Override
     public final Waiter allowWait(Waiter waiter, Waiter owner) {
-        int res = txIdComparator().compare(waiter.txId(), owner.txId());
+        int res = TransactionIds.compare(waiter.txId(), owner.txId());
         assert res != 0;
 
         // Waiter is allowed to wait for owner if it has higher priority.

modules/transactions/src/main/java/org/apache/ignite/internal/tx/impl/WoundWaitDeadlockPreventionPolicy.java

@@ -18,6 +18,7 @@
 package org.apache.ignite.internal.tx.impl;
 
 import org.apache.ignite.internal.tx.DeadlockPreventionPolicy;
+import org.apache.ignite.internal.tx.TransactionIds;
 import org.apache.ignite.internal.tx.Waiter;
 
 /**
@@ -33,7 +34,7 @@
 public class WoundWaitDeadlockPreventionPolicy implements DeadlockPreventionPolicy {
     @Override
     public Waiter allowWait(Waiter waiter, Waiter owner) {
-        int res = txIdComparator().compare(waiter.txId(), owner.txId());
+        int res = TransactionIds.compare(waiter.txId(), owner.txId());
         assert res != 0;
 
         // Waiter is allowed to wait for owner if it has lower priority.