From b308a894cf3ecfa288d638f01c143575dd12b5b6 Mon Sep 17 00:00:00 2001
From: Peter Levart <plevart@openjdk.org>
Date: Mon, 4 May 2015 10:13:19 +0200
Subject: [PATCH] 8074003:
 java.time.zone.ZoneRules.getOffset(java.time.Instant) can be optimized

Make epochSecond part of ZoneOffsetTransition so it doesn't have to be recomputed frequently

Reviewed-by: scolebourne, rriggs
---
 .../java/time/zone/ZoneOffsetTransition.java  | 21 +++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/jdk/src/java.base/share/classes/java/time/zone/ZoneOffsetTransition.java b/jdk/src/java.base/share/classes/java/time/zone/ZoneOffsetTransition.java
index 5f05338bd09..32ab6b82ddf 100644
--- a/jdk/src/java.base/share/classes/java/time/zone/ZoneOffsetTransition.java
+++ b/jdk/src/java.base/share/classes/java/time/zone/ZoneOffsetTransition.java
@@ -103,6 +103,10 @@ public final class ZoneOffsetTransition
      * Serialization version.
      */
     private static final long serialVersionUID = -6946044323557704546L;
+    /**
+     * The transition epoch-second.
+     */
+    private final long epochSecond;
     /**
      * The local transition date-time at the transition.
      */
@@ -152,6 +156,7 @@ public final class ZoneOffsetTransition
      * @param offsetAfter  the offset at and after the transition, not null
      */
     ZoneOffsetTransition(LocalDateTime transition, ZoneOffset offsetBefore, ZoneOffset offsetAfter) {
+        this.epochSecond = transition.toEpochSecond(offsetBefore);
         this.transition = transition;
         this.offsetBefore = offsetBefore;
         this.offsetAfter = offsetAfter;
@@ -165,6 +170,7 @@ public final class ZoneOffsetTransition
      * @param offsetAfter  the offset at and after the transition, not null
      */
     ZoneOffsetTransition(long epochSecond, ZoneOffset offsetBefore, ZoneOffset offsetAfter) {
+        this.epochSecond = epochSecond;
         this.transition = LocalDateTime.ofEpochSecond(epochSecond, 0, offsetBefore);
         this.offsetBefore = offsetBefore;
         this.offsetAfter = offsetAfter;
@@ -209,7 +215,7 @@ public final class ZoneOffsetTransition
      * @throws IOException if an error occurs
      */
     void writeExternal(DataOutput out) throws IOException {
-        Ser.writeEpochSec(toEpochSecond(), out);
+        Ser.writeEpochSec(epochSecond, out);
         Ser.writeOffset(offsetBefore, out);
         Ser.writeOffset(offsetAfter, out);
     }
@@ -253,7 +259,7 @@ public final class ZoneOffsetTransition
      * @return the transition epoch second
      */
     public long toEpochSecond() {
-        return transition.toEpochSecond(offsetBefore);
+        return epochSecond;
     }
 
     //-------------------------------------------------------------------------
@@ -397,7 +403,13 @@ public final class ZoneOffsetTransition
      */
     @Override
     public int compareTo(ZoneOffsetTransition transition) {
-        return this.getInstant().compareTo(transition.getInstant());
+        if (epochSecond < transition.epochSecond) {
+            return -1;
+        } else if (epochSecond > transition.epochSecond) {
+            return 1;
+        } else {
+            return this.getInstant().compareTo(transition.getInstant());
+        }
     }
 
     //-----------------------------------------------------------------------
@@ -416,7 +428,8 @@ public final class ZoneOffsetTransition
         }
         if (other instanceof ZoneOffsetTransition) {
             ZoneOffsetTransition d = (ZoneOffsetTransition) other;
-            return transition.equals(d.transition) &&
+            return epochSecond == d.epochSecond &&
+                transition.equals(d.transition) &&
                 offsetBefore.equals(d.offsetBefore) && offsetAfter.equals(d.offsetAfter);
         }
         return false;