feat: assignment and bandit caching

build.gradle

@@ -11,7 +11,7 @@ java {
 }
 
 group = 'cloud.eppo'
-version = '3.1.1-SNAPSHOT'
+version = '3.2.0-SNAPSHOT'
 ext.isReleaseVersion = !version.endsWith("SNAPSHOT")
 
 import org.apache.tools.ant.filters.ReplaceTokens
@@ -31,16 +31,17 @@ repositories {
 
 dependencies {
   // Re-export classes and interfaces that will be used upstream
-  api 'cloud.eppo:sdk-common-jvm:3.3.1'
+  api 'cloud.eppo:sdk-common-jvm:3.5.0'
 
   implementation 'com.github.zafarkhaja:java-semver:0.10.2'
   implementation 'com.fasterxml.jackson.core:jackson-databind:2.17.1'
   implementation 'org.ehcache:ehcache:3.10.8'
   implementation 'org.slf4j:slf4j-api:2.0.13'
   // Logback classic 1.3.x is compatible with java 8
   implementation 'ch.qos.logback:logback-classic:1.3.14'
+  implementation 'org.jetbrains:annotations:13.0'
 
-  testImplementation 'cloud.eppo:sdk-common-jvm:3.2.0-SNAPSHOT:tests'
+  testImplementation 'cloud.eppo:sdk-common-jvm:3.5.0:tests'
   testImplementation platform('org.junit:junit-bom:5.10.2')
   testImplementation 'org.junit.jupiter:junit-jupiter'
   testImplementation 'com.github.tomakehurst:wiremock-jre8:2.35.2'

src/main/java/com/eppo/sdk/EppoClient.java

@@ -1,11 +1,16 @@
 package com.eppo.sdk;
 
 import cloud.eppo.BaseEppoClient;
+import cloud.eppo.api.IAssignmentCache;
+import cloud.eppo.cache.ExpiringInMemoryAssignmentCache;
+import cloud.eppo.cache.LRUInMemoryAssignmentCache;
 import cloud.eppo.logging.AssignmentLogger;
 import cloud.eppo.logging.BanditLogger;
 import com.eppo.sdk.helpers.AppDetails;
 import com.eppo.sdk.helpers.FetchConfigurationsTask;
 import java.util.Timer;
+import java.util.concurrent.TimeUnit;
+import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -39,9 +44,11 @@ private EppoClient(
       String host,
       String sdkName,
       String sdkVersion,
-      AssignmentLogger assignmentLogger,
-      BanditLogger banditLogger,
-      boolean isGracefulModel) {
+      @Nullable AssignmentLogger assignmentLogger,
+      @Nullable BanditLogger banditLogger,
+      boolean isGracefulMode,
+      @Nullable IAssignmentCache assignmentCache,
+      @Nullable IAssignmentCache banditAssignmentCache) {
     super(
         apiKey,
         host,
@@ -50,10 +57,12 @@ private EppoClient(
         assignmentLogger,
         banditLogger,
         null,
-        isGracefulModel,
+        isGracefulMode,
         false,
         true,
-        null);
+        null,
+        assignmentCache,
+        banditAssignmentCache);
   }
 
   /** Stops the client from polling Eppo for updated flag and bandit configurations */
@@ -73,6 +82,12 @@ public static class Builder {
     private long pollingIntervalMs = DEFAULT_POLLING_INTERVAL_MS;
     private String host = DEFAULT_HOST;
 
+    // Assignment and bandit caching on by default. To disable, call
+    // `builder.assignmentCache(null).banditAssignmentCache(null);`
+    private IAssignmentCache assignmentCache = new LRUInMemoryAssignmentCache(100);
+    private IAssignmentCache banditAssignmentCache =
+        new ExpiringInMemoryAssignmentCache(10, TimeUnit.MINUTES);
+
     /** Sets the API Key--created within the eppo application--to use. This is required. */
     public Builder apiKey(String apiKey) {
       this.apiKey = apiKey;
@@ -135,6 +150,16 @@ public Builder host(String host) {
       return this;
     }
 
+    public Builder assignmentCache(IAssignmentCache assignmentCache) {
+      this.assignmentCache = assignmentCache;
+      return this;
+    }
+
+    public Builder banditAssignmentCache(IAssignmentCache banditAssignmentCache) {
+      this.banditAssignmentCache = banditAssignmentCache;
+      return this;
+    }
+
     public EppoClient buildAndInit() {
       AppDetails appDetails = AppDetails.getInstance();
       String sdkName = appDetails.getName();
@@ -153,7 +178,15 @@ public EppoClient buildAndInit() {
 
       instance =
           new EppoClient(
-              apiKey, sdkName, sdkVersion, host, assignmentLogger, banditLogger, isGracefulMode);
+              apiKey,
+              sdkName,
+              sdkVersion,
+              host,
+              assignmentLogger,
+              banditLogger,
+              isGracefulMode,
+              assignmentCache,
+              banditAssignmentCache);
 
       // Stop any active polling
       stopPolling();