Merge pull request #334 from trytocatch/master

Solve: the dynamically updated property value cannot be obtained, and the concurrency problem

jasypt-spring-boot/src/main/java/com/ulisesbocchio/jasyptspringboot/caching/CachingDelegateEncryptablePropertySource.java

@@ -3,9 +3,12 @@
 import com.ulisesbocchio.jasyptspringboot.EncryptablePropertyFilter;
 import com.ulisesbocchio.jasyptspringboot.EncryptablePropertyResolver;
 import com.ulisesbocchio.jasyptspringboot.EncryptablePropertySource;
-import java.util.HashMap;
+
 import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
 
+import lombok.AllArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.core.env.PropertySource;
 import org.springframework.util.Assert;
@@ -15,7 +18,7 @@ public class CachingDelegateEncryptablePropertySource<T> extends PropertySource<
     private final PropertySource<T> delegate;
     private final EncryptablePropertyResolver resolver;
     private final EncryptablePropertyFilter filter;
-    private final Map<String, Object> cache;
+    private final Map<String, CachedValue> cache;
 
     public CachingDelegateEncryptablePropertySource(PropertySource<T> delegate, EncryptablePropertyResolver resolver, EncryptablePropertyFilter filter) {
         super(delegate.getName(), delegate.getSource());
@@ -25,7 +28,7 @@ public CachingDelegateEncryptablePropertySource(PropertySource<T> delegate, Encr
         this.delegate = delegate;
         this.resolver = resolver;
         this.filter = filter;
-        this.cache = new HashMap<>();
+        this.cache = new ConcurrentHashMap<>();
     }
 
     @Override
@@ -35,24 +38,48 @@ public PropertySource<T> getDelegate() {
 
     @Override
     public Object getProperty(String name) {
-        // Can be called recursively, so, we cannot use computeIfAbsent.
-        if (cache.containsKey(name)) {
-            return cache.get(name);
+        //The purpose of this cache is to reduce the cost of decryption,
+        // so it's not a bad idea to read the original property every time, it's generally fast.
+        Object originValue = delegate.getProperty(name);
+        if (!(originValue instanceof String)) {
+            //Because we read the original property every time, if it isn't a String,
+            // there's no point in caching it.
+            return originValue;
+        }
+
+        CachedValue cachedValue = cache.get(name);
+        if (cachedValue != null && Objects.equals(originValue, cachedValue.originValue)) {
+            // If the original property has not changed, it is safe to return the cached result.
+            return cachedValue.resolvedValue;
         }
-        synchronized (name.intern()) {
-            if (!cache.containsKey(name)) {
-                Object resolved = getProperty(resolver, filter, delegate, name);
-                if (resolved != null) {
-                    cache.put(name, resolved);
-                }
+
+        //originValue must be String here
+        if (filter.shouldInclude(delegate, name)) {
+            String originStringValue = (String) originValue;
+            String resolved = resolver.resolvePropertyValue(originStringValue);
+            CachedValue newCachedValue = new CachedValue(originStringValue, resolved);
+            //If the mapping relationship in the cache changes during
+            // the calculation process, then ignore it directly.
+            if (cachedValue == null) {
+                cache.putIfAbsent(name, newCachedValue);
+            } else {
+                cache.replace(name, cachedValue, newCachedValue);
             }
-            return cache.get(name);
+            //return the result calculated this time
+            return resolved;
         }
+        return originValue;
     }
 
     @Override
     public void refresh() {
         log.info("Property Source {} refreshed", delegate.getName());
         cache.clear();
     }
+
+    @AllArgsConstructor
+    private static class CachedValue {
+        private final String originValue;
+        private final String resolvedValue;
+    }
 }