Author: etnu
Date: Sat Oct 18 11:38:25 2008
New Revision: 705904
URL: http://svn.apache.org/viewvc?rev=705904&view=rev
Log:
Added negative caching to BasicGadgetSpecFactory to prevent re-parsing /
re-fetching of gadgets in a known error state. This saves a substantial amount
of CPU time over the current implementation, which re-parses on every render
even when caching is turned on.
Modified:
incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/BasicGadgetSpecFactory.java
incubator/shindig/trunk/java/gadgets/src/test/java/org/apache/shindig/gadgets/BasicGadgetSpecFactoryTest.java
Modified:
incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/BasicGadgetSpecFactory.java
URL:
http://svn.apache.org/viewvc/incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/BasicGadgetSpecFactory.java?rev=705904&r1=705903&r2=705904&view=diff
==============================================================================
---
incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/BasicGadgetSpecFactory.java
(original)
+++
incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/BasicGadgetSpecFactory.java
Sat Oct 18 11:38:25 2008
@@ -40,7 +40,8 @@
public class BasicGadgetSpecFactory implements GadgetSpecFactory {
static final String RAW_GADGETSPEC_XML_PARAM_NAME = "rawxml";
static final Uri RAW_GADGET_URI = Uri.parse("http://localhost/raw.xml";);
-
+ static final String ERROR_SPEC = "<Module><ModulePrefs
title='Error'/><Content/></Module>";
+ static final String ERROR_KEY = "parse.exception";
static final Logger logger =
Logger.getLogger(BasicGadgetSpecFactory.class.getName());
private final HttpFetcher fetcher;
@@ -48,7 +49,7 @@
private final long minTtl;
private final long maxTtl;
- @Inject
+ @Inject
public BasicGadgetSpecFactory(HttpFetcher fetcher,
CacheProvider cacheProvider,
@Named("shindig.gadget-spec.cache.capacity")
int capacity,
@@ -89,15 +90,25 @@
try {
return fetchObjectAndCache(uri, ignoreCache);
} catch (GadgetException e) {
- // Failed to re-fetch raw object. Use cached object if it exists.
- if (cached.obj == null) {
- throw e;
+ // Enforce negative caching.
+ GadgetSpec spec;
+ if (cached.obj != null) {
+ spec = cached.obj;
} else {
- logger.info("GadgetSpec fetch failed for " + uri + " - using
cached.");
+ // We create this dummy spec to avoid the cost of re-parsing when a
remote site is out.
+ spec = new GadgetSpec(uri, ERROR_SPEC);
+ spec.setAttribute(ERROR_KEY, e);
+ cached.obj = spec;
}
+ logger.info("GadgetSpec fetch failed for " + uri + " - using cached
for " + minTtl + " ms");
+ ttlCache.addElementWithTtl(uri, spec, minTtl);
}
}
+ GadgetException exception = (GadgetException)
cached.obj.getAttribute(ERROR_KEY);
+ if (exception != null) {
+ throw exception;
+ }
return cached.obj;
}
Modified:
incubator/shindig/trunk/java/gadgets/src/test/java/org/apache/shindig/gadgets/BasicGadgetSpecFactoryTest.java
URL:
http://svn.apache.org/viewvc/incubator/shindig/trunk/java/gadgets/src/test/java/org/apache/shindig/gadgets/BasicGadgetSpecFactoryTest.java?rev=705904&r1=705903&r2=705904&view=diff
==============================================================================
---
incubator/shindig/trunk/java/gadgets/src/test/java/org/apache/shindig/gadgets/BasicGadgetSpecFactoryTest.java
(original)
+++
incubator/shindig/trunk/java/gadgets/src/test/java/org/apache/shindig/gadgets/BasicGadgetSpecFactoryTest.java
Sat Oct 18 11:38:25 2008
@@ -21,6 +21,7 @@
import static org.easymock.EasyMock.expect;
import static org.easymock.classextension.EasyMock.replay;
import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
import org.apache.shindig.common.cache.CacheProvider;
import org.apache.shindig.common.cache.DefaultCacheProvider;
@@ -103,7 +104,7 @@
private final CacheProvider cacheProvider = new DefaultCacheProvider();
private final BasicGadgetSpecFactory specFactory
- = new BasicGadgetSpecFactory(fetcher, cacheProvider, 5, -1000, 1000);
+ = new BasicGadgetSpecFactory(fetcher, cacheProvider, 5, 1000, 1000);
@Test
public void specFetched() throws Exception {
@@ -220,6 +221,45 @@
}
@Test(expected = GadgetException.class)
+ public void badFetchServesCached() throws Exception {
+ HttpRequest firstRequest = new HttpRequest(SPEC_URL).setIgnoreCache(false);
+ expect(fetcher.fetch(firstRequest)).andReturn(new
HttpResponse(LOCAL_SPEC_XML)).once();
+ HttpRequest secondRequest = new HttpRequest(SPEC_URL).setIgnoreCache(true);
+
expect(fetcher.fetch(secondRequest)).andReturn(HttpResponse.error()).once();
+ replay(fetcher);
+
+ GadgetSpec original = specFactory.getGadgetSpec(SPEC_URL.toJavaUri(),
false);
+ GadgetSpec cached = specFactory.getGadgetSpec(SPEC_URL.toJavaUri(), true);
+
+ assertEquals(original.getUrl(), cached.getUrl());
+ assertEquals(original.getChecksum(), cached.getChecksum());
+ }
+
+ @Test(expected = GadgetException.class)
+ public void malformedGadgetSpecThrows() throws Exception {
+ HttpRequest request = new HttpRequest(SPEC_URL).setIgnoreCache(true);
+ expect(fetcher.fetch(request)).andReturn(new HttpResponse("malformed
junk"));
+ replay(fetcher);
+
+ specFactory.getGadgetSpec(SPEC_URL.toJavaUri(), true);
+ }
+
+ @Test(expected = GadgetException.class)
+ public void malformedGadgetSpecIsCachedAndThrows() throws Exception {
+ HttpRequest request = new HttpRequest(SPEC_URL).setIgnoreCache(false);
+ expect(fetcher.fetch(request)).andReturn(new HttpResponse("malformed
junk")).once();
+ replay(fetcher);
+
+ try {
+ specFactory.getGadgetSpec(SPEC_URL.toJavaUri(), false);
+ fail("No exception thrown on bad parse");
+ } catch (GadgetException e) {
+ // Expected.
+ }
+ specFactory.getGadgetSpec(SPEC_URL.toJavaUri(), false);
+ }
+
+ @Test(expected = GadgetException.class)
public void throwingFetcherRethrows() throws Exception {
HttpRequest request = new HttpRequest(SPEC_URL).setIgnoreCache(true);
expect(fetcher.fetch(request)).andThrow(
