Add optimistic fast path for putIfAbsent to avoid locking

This mirrors the optimization in computeIfAbsent, which only locks
if the lookup failed and the value may need to be computed.

See apache/openwhisk#2797 for a use-case
where the users had to modify their usage to obtain their
performance goals.

README.md

@@ -53,7 +53,6 @@ Use Caffeine in a community provided integration:
  * [ScalaCache][scala-cache]: Simple caching in Scala
  * [Camel][camel]: Routing and mediation engine
  * [JHipster][jhipster]: Generate, develop, deploy
- * [Druid][druid]: Real-time analytics
 
 Powering infrastructure near you:
  * [Dropwizard][dropwizard]: Ops-friendly, high-performance, RESTful APIs
@@ -62,11 +61,12 @@ Powering infrastructure near you:
  * [HBase][hbase]: A distributed, scalable, big data store
  * [Apache Solr][solr]: Blazingly fast enterprise search
  * [Infinispan][infinispan]: Distributed in-memory data grid
+ * [OpenWhisk][open-whisk]: Serverless cloud platform
  * [Corfu][corfu]: A cluster consistency platform
  * [Grails][grails]: Groovy-based web framework
- * [Orbit][orbit]: Virtual actors on the JVM
  * [Finagle][finagle]: Extensible RPC system
  * [Neo4j][neo4j]: Graphs for Everyone
+ * [Druid][druid]: Real-time analytics
 
 ### In the News
 
@@ -130,7 +130,7 @@ Snapshots of the development version are available in
 [finagle]: https://github.com/twitter/finagle
 [druid]: https://druid.apache.org/docs/latest/configuration/index.html#cache-configuration
 [jhipster]: https://www.jhipster.tech/
-[orbit]: https://github.com/orbit/orbit
+[open-whisk]: https://openwhisk.apache.org/
 [camel]: https://github.com/apache/camel/blob/master/components/camel-caffeine/src/main/docs/caffeine-cache-component.adoc
 [corfu]: https://github.com/CorfuDB/CorfuDB
 [akka-http]: https://doc.akka.io/docs/akka-http/current/common/caching.html

caffeine/src/main/java/com/github/benmanes/caffeine/cache/BoundedLocalCache.java

@@ -2006,6 +2006,17 @@ public Map<K, V> getAllPresent(Iterable<?> keys) {
             return null;
           }
         }
+      } else if (onlyIfAbsent) {
+        // An optimistic fast path to avoid unnecessary locking
+        V currentValue = prior.getValue();
+        if ((currentValue != null) && !hasExpired(prior, now)) {
+          if (!isComputingAsync(prior)) {
+            tryExpireAfterRead(prior, key, currentValue, expiry(), now);
+            setAccessTime(prior, now);
+          }
+          afterRead(prior, now, /* recordHit */ false);
+          return currentValue;
+        }
       }
 
       V oldValue;

checksum.xml

@@ -45,6 +45,7 @@
     <trusted-key id='476634a4694e716a' group='com.googlecode.java-diff-utils' />
     <trusted-key id='72475fd306b9cab7' group='com.googlecode.javaewah' />
     <trusted-key id='80c08b1c29100955' group='com.jakewharton.fliptables' />
+    <trusted-key id='e0cb7823cfd00fbf' group='com.jakewharton.fliptables' />
     <trusted-key id='a50569c7ca7fa1f0' group='com.jcraft' />
     <trusted-key id='52931f4b72b4f54c' group='com.koloboke' />
     <trusted-key id='1063fe98bcecb758' group='com.puppycrawl.tools' />
@@ -204,6 +205,9 @@
     <dependency group='com.github.ben-manes' module='gradle-versions-plugin' version='0.27.0'>
       <sha512>EEA3D1118C6DE8F890AB6A04EA3505C149F99C034C26707C44ED736F6603C6253A03BA07D0361C4D1008E5CE944B0DD7457DC1AF2CD6B01091F6594261DB1F77</sha512>
     </dependency>
+    <dependency group='com.github.ben-manes' module='gradle-versions-plugin' version='0.28.0'>
+      <sha512>6B6E1C845DF98A6EFD07354F7DC2FABB77FFB171F20BE88BC232270AEB0243370B5265E2A310D8CBAC77F83F2B0D11AE8EB59A9ED1F030D5789357DA3899798B</sha512>
+    </dependency>
     <dependency group='com.github.brianfrankcooper.YCSB' module='core' version='0.15.0'>
       <sha512>DF5BFED7DFC327166FE0CB81BD6A9655F44CCB268E7E69204BD09955147CE9A97EBBCC28F9ACF315DBAF49E850A43CE8744F44E68D7BE816EACCAF0BEE41B203</sha512>
     </dependency>
@@ -342,6 +346,9 @@
     <dependency group='org.testng' module='testng' version='7.1.1'>
       <sha512>508B1F1594A3E377DD9AEBA9EF1EF43DA24F22BE488B4AF9EDB719D02814741B47AD69D22A7E8CAF799D847A5CE20DE8B199586958AECA17C79EFDCA8D257E</sha512>
     </dependency>
+    <dependency group='org.testng' module='testng' version='7.2.0'>
+      <sha512>AC7BBD700CB88EDB3E0FC92D7A0D659F42C97E6E0B5E21DD3EC2EC8537841CAEA50E99AC3414026BFE54D89EA72F6F635F964B429EC8A1E5BF6F44101AC58868</sha512>
+    </dependency>
     <dependency group='xerces' module='xercesImpl' version='2.9.1'>
       <sha512>37A13B129F3536A53F2A553151A53997DA6DE7CE4D7231EFEEFD26A68C92BE309666F2EE1F527D3B8C38BC6ADDC9FCCBBDD0D134759FD88667976B0CFF842435</sha512>
     </dependency>

gradle/dependencies.gradle

@@ -25,23 +25,23 @@
  */
 ext {
   versions = [
-    akka: '2.6.3',
+    akka: '2.6.4',
     cache2k: '1.3.1.Alpha',
-    checkerFramework: '3.1.0',
+    checkerFramework: '3.2.0',
     collision: '0.3.3',
-    commonsCompress: '1.19',
+    commonsCompress: '1.20',
     commonsLang3: '3.9',
     commonsMath3: '3.6.1',
     concurrentlinkedhashmap: '1.4.2',
     config: '1.4.0',
     ehcache3: '3.8.1',
     errorprone: '2.3.4',
     errorproneJavac: '9+181-r4173-1',
-    elasticSearch: '7.5.2',
+    elasticSearch: '7.6.1',
     expiringMap: '0.5.9',
     fastfilter: 'bf0b02297f',
-    fastutil: '8.3.0',
-    flipTables: '1.0.2',
+    fastutil: '8.3.1',
+    flipTables: '1.1.0',
     guava: '28.2-jre',
     jackrabbit: '1.24.0',
     jamm: '0.3.3',
@@ -68,30 +68,30 @@ ext {
     jcacheTck: '1.1.1',
     jctools: '3.0.0',
     junit: '4.13',
-    mockito: '3.2.4',
+    mockito: '3.3.3',
     paxExam: '4.13.1',
-    testng: '7.1.1',
+    testng: '7.2.0',
     truth: '0.24',
   ]
   pluginVersions = [
     apt: '0.21',
     bnd: '5.0.0',
-    checkstyle: '8.29',
+    checkstyle: '8.30',
     coveralls: '2.8.4',
     coverity: '1.0.10',
     errorprone: '1.1.1',
     jacoco: '0.8.4',
     jmh: '0.5.0',
     jmhReport: '0.9.0',
     nullaway: '1.0.1',
-    pmd: '6.21.0',
+    pmd: '6.22.0',
     semanticVersioning: '1.1.0',
     shadow: '5.2.0',
     sonarqube: '2.8.0.1969',
     spotbugs: '4.0.0-RC1',
     spotbugsPlugin: '3.0.0',
     stats: '0.2.2',
-    versions: '0.27.0',
+    versions: '0.28.0',
   ]
 
   libraries = [
@@ -166,7 +166,7 @@ ext {
         exclude group: 'junit'
         exclude group: 'guice'
       },
-      'com.google.inject:guice:4.2.2'
+      'com.google.inject:guice:4.2.3'
     ],
     truth: "com.google.truth:truth:${testVersions.truth}",
   ]

gradle/wrapper/gradle-wrapper.properties

@@ -1,4 +1,4 @@
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.1.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.3-rc-4-bin.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME