Fix #34443: fix memory leak in SpecExpressionResolver

Author: LEDfan

src/main/java/eu/openanalytics/containerproxy/spec/expression/SpecExpressionResolver.java

@@ -22,7 +22,9 @@
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.node.ArrayNode;
-import com.google.common.base.Throwables;
+import com.github.benmanes.caffeine.cache.Cache;
+import com.github.benmanes.caffeine.cache.Caffeine;
+import com.github.benmanes.caffeine.cache.Scheduler;
 import org.springframework.beans.factory.config.ConfigurableBeanFactory;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ConfigurableApplicationContext;
@@ -45,8 +47,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.TimeUnit;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
@@ -58,7 +59,10 @@ public class SpecExpressionResolver {
 
     private final ApplicationContext appContext;
     private final ExpressionParser expressionParser;
-    private final Map<SpecExpressionContext, StandardEvaluationContext> evaluationCache = new ConcurrentHashMap<>(8);
+    private final Cache<SpecExpressionContext, StandardEvaluationContext> evaluationCache =  Caffeine.newBuilder()
+        .scheduler(Scheduler.systemScheduler())
+        .expireAfterAccess(1, TimeUnit.MINUTES)
+        .build();
 
     private final ParserContext beanExpressionParserContext = new ParserContext() {
         @Override
@@ -91,20 +95,19 @@ public <T> T evaluate(String expression, SpecExpressionContext context, Class<T>
 
             ConfigurableBeanFactory beanFactory = ((ConfigurableApplicationContext) appContext).getBeanFactory();
 
-            StandardEvaluationContext sec = evaluationCache.get(context);
-            if (sec == null) {
-                sec = new StandardEvaluationContext();
-                sec.setRootObject(context);
-                sec.addPropertyAccessor(new BeanExpressionContextAccessor());
-                sec.addPropertyAccessor(new BeanFactoryAccessor());
-                sec.addPropertyAccessor(new MapAccessor());
-                sec.addPropertyAccessor(new EnvironmentAccessor());
-                sec.setBeanResolver(new BeanFactoryResolver(appContext));
-                sec.setTypeLocator(new StandardTypeLocator(beanFactory.getBeanClassLoader()));
+            StandardEvaluationContext sec = evaluationCache.get(context, k -> {
+                StandardEvaluationContext result = new StandardEvaluationContext();
+                result.setRootObject(context);
+                result.addPropertyAccessor(new BeanExpressionContextAccessor());
+                result.addPropertyAccessor(new BeanFactoryAccessor());
+                result.addPropertyAccessor(new MapAccessor());
+                result.addPropertyAccessor(new EnvironmentAccessor());
+                result.setBeanResolver(new BeanFactoryResolver(appContext));
+                result.setTypeLocator(new StandardTypeLocator(beanFactory.getBeanClassLoader()));
                 ConversionService conversionService = beanFactory.getConversionService();
-                if (conversionService != null) sec.setTypeConverter(new StandardTypeConverter(conversionService));
-                evaluationCache.put(context, sec);
-            }
+                if (conversionService != null) result.setTypeConverter(new StandardTypeConverter(conversionService));
+                return result;
+            });
 
             return expr.getValue(sec, resType);
         } catch (ExpressionException ex) {