Closes PR #77

Avoid fetching the cached entity twice on cache hit.

httpclient-cache/src/main/java/org/apache/http/impl/client/cache/CachingExec.java

@@ -263,10 +263,9 @@ public class CachingExec implements ClientExecChain {
         requestCompliance.makeRequestCompliant(request);
         request.addHeader("Via",via);
 
-        flushEntriesInvalidatedByRequest(context.getTargetHost(), request);
-
         if (!cacheableRequestPolicy.isServableFromCache(request)) {
             log.debug("Request is not servable from cache");
+            flushEntriesInvalidatedByRequest(context.getTargetHost(), request);
             return callBackend(route, request, context, execAware);
         }
 

httpclient-cache/src/test/java/org/apache/http/impl/client/cache/TestCachingExec.java

@@ -402,6 +402,26 @@ public class TestCachingExec extends TestCachingExecChain {
         verifyMocks();
     }
 
+    @Test
+    public void testDoesNotFlushCachesOnCacheHit() throws Exception {
+        requestPolicyAllowsCaching(true);
+        requestIsFatallyNonCompliant(null);
+
+        getCacheEntryReturns(mockCacheEntry);
+        doesNotFlushCache();
+        cacheEntrySuitable(true);
+        cacheEntryValidatable(true);
+
+        expect(mockResponseGenerator.generateResponse(isA(HttpRequestWrapper.class), isA(HttpCacheEntry.class)))
+                .andReturn(mockBackendResponse);
+
+        replayMocks();
+        final HttpResponse result = impl.execute(route, request, context);
+        verifyMocks();
+
+        Assert.assertSame(mockBackendResponse, result);
+    }
+
     private IExpectationSetters<CloseableHttpResponse> implExpectsAnyRequestAndReturn(
             final CloseableHttpResponse response) throws Exception {
         final CloseableHttpResponse resp = impl.callBackend(

httpclient-cache/src/test/java/org/apache/http/impl/client/cache/TestCachingExecChain.java

@@ -1777,4 +1777,9 @@ public abstract class TestCachingExecChain {
             .andReturn(mockCachedResponse);
     }
 
+    protected void doesNotFlushCache() throws IOException {
+        mockCache.flushInvalidatedCacheEntriesFor(isA(HttpHost.class), isA(HttpRequest.class));
+        EasyMock.expectLastCall().andThrow(new AssertionError("flushInvalidatedCacheEntriesFor should not have been called")).anyTimes();
+    }
+
 }