feat: assignment and bandit caching

build.gradle

@@ -11,7 +11,7 @@ java {
 }
 
 group = 'cloud.eppo'
-version = '3.0.2-SNAPSHOT'
+version = '3.1.0'
 ext.isReleaseVersion = !version.endsWith("SNAPSHOT")
 
 import org.apache.tools.ant.filters.ReplaceTokens
@@ -31,7 +31,7 @@ repositories {
 
 dependencies {
   // Re-export classes and interfaces that will be used upstream
-  api 'cloud.eppo:sdk-common-jvm:3.0.2'
+  api 'cloud.eppo:sdk-common-jvm:3.5.0-SNAPSHOT'
 
   implementation 'com.github.zafarkhaja:java-semver:0.10.2'
   implementation 'com.fasterxml.jackson.core:jackson-databind:2.17.1'
@@ -40,7 +40,7 @@ dependencies {
   // Logback classic 1.3.x is compatible with java 8
   implementation 'ch.qos.logback:logback-classic:1.3.14'
 
-  testImplementation 'cloud.eppo:sdk-common-jvm:3.0.0-SNAPSHOT:tests'
+  testImplementation 'cloud.eppo:sdk-common-jvm:3.2.0-SNAPSHOT: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 +1,15 @@
 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.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -41,9 +45,23 @@ private EppoClient(
       String sdkVersion,
       AssignmentLogger assignmentLogger,
       BanditLogger banditLogger,
-      boolean isGracefulModel) {
+      boolean isGracefulModel,
+      IAssignmentCache assignmentCache,
+      IAssignmentCache banditAssignmentCache) {
     super(
-        apiKey, host, sdkName, sdkVersion, assignmentLogger, banditLogger, isGracefulModel, false);
+        apiKey,
+        host,
+        sdkName,
+        sdkVersion,
+        assignmentLogger,
+        banditLogger,
+        null,
+        isGracefulModel,
+        false,
+        true,
+        null,
+        assignmentCache,
+        banditAssignmentCache);
   }
 
   /** Stops the client from polling Eppo for updated flag and bandit configurations */
@@ -63,6 +81,12 @@ 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;
@@ -125,6 +149,16 @@ 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();
@@ -143,7 +177,15 @@ 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();

src/test/java/com/eppo/sdk/EppoClientTest.java

@@ -276,7 +276,7 @@ private void uninitClient() {
   private void initBuggyClient() {
     try {
       EppoClient eppoClient = initClient(DUMMY_FLAG_API_KEY);
-      Field configurationStoreField = BaseEppoClient.class.getDeclaredField("requestor");
+      Field configurationStoreField = BaseEppoClient.class.getDeclaredField("configurationStore");
       configurationStoreField.setAccessible(true);
       configurationStoreField.set(eppoClient, null);
     } catch (NoSuchFieldException | IllegalAccessException e) {