Author: cutting
Date: Wed Feb 21 12:32:51 2007
New Revision: 510188
URL: http://svn.apache.org/viewvc?view=rev&rev=510188
Log:
HADOOP-1017. Cache constructors. Contributed by Ron Bodkin.
Added:
lucene/hadoop/trunk/src/test/org/apache/hadoop/util/
lucene/hadoop/trunk/src/test/org/apache/hadoop/util/TestReflectionUtils.java
Modified:
lucene/hadoop/trunk/CHANGES.txt
lucene/hadoop/trunk/src/java/org/apache/hadoop/util/ReflectionUtils.java
Modified: lucene/hadoop/trunk/CHANGES.txt
URL:
http://svn.apache.org/viewvc/lucene/hadoop/trunk/CHANGES.txt?view=diff&rev=510188&r1=510187&r2=510188
==============================================================================
--- lucene/hadoop/trunk/CHANGES.txt (original)
+++ lucene/hadoop/trunk/CHANGES.txt Wed Feb 21 12:32:51 2007
@@ -78,6 +78,9 @@
namenode and jobtracker with include and exclude files. (Wendy
Chien via cutting)
+24. HADOOP-1017. Cache constructors, for improved performance.
+ (Ron Bodkin via cutting)
+
Release 0.11.2 - 2007-02-16
Modified:
lucene/hadoop/trunk/src/java/org/apache/hadoop/util/ReflectionUtils.java
URL:
http://svn.apache.org/viewvc/lucene/hadoop/trunk/src/java/org/apache/hadoop/util/ReflectionUtils.java?view=diff&rev=510188&r1=510187&r2=510188
==============================================================================
--- lucene/hadoop/trunk/src/java/org/apache/hadoop/util/ReflectionUtils.java
(original)
+++ lucene/hadoop/trunk/src/java/org/apache/hadoop/util/ReflectionUtils.java
Wed Feb 21 12:32:51 2007
@@ -21,6 +21,8 @@
import java.lang.reflect.Constructor;
import java.io.*;
import java.lang.management.*;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
import org.apache.commons.logging.Log;
import org.apache.hadoop.conf.*;
@@ -33,6 +35,12 @@
public class ReflectionUtils {
private static final Class[] emptyArray = new Class[]{};
+ /**
+ * Cache of constructors for each class. Pins the classes so they
+ * can't be garbage collected until ReflectionUtils can be collected.
+ */
+ private static final Map<Class<?>, Constructor<?>> CONSTRUCTOR_CACHE =
+ new ConcurrentHashMap<Class<?>, Constructor<?>>();
/**
* Check and set 'configuration' if necessary.
@@ -61,8 +69,12 @@
public static Object newInstance(Class theClass, Configuration conf) {
Object result;
try {
- Constructor meth = theClass.getDeclaredConstructor(emptyArray);
- meth.setAccessible(true);
+ Constructor meth = CONSTRUCTOR_CACHE.get(theClass);
+ if (meth == null) {
+ meth = theClass.getDeclaredConstructor(emptyArray);
+ meth.setAccessible(true);
+ CONSTRUCTOR_CACHE.put(theClass, meth);
+ }
result = meth.newInstance();
} catch (Exception e) {
throw new RuntimeException(e);
@@ -152,4 +164,14 @@
}
}
}
+
+ // methods to support testing
+ static void clearCache() {
+ CONSTRUCTOR_CACHE.clear();
+ }
+
+ static int getCacheSize() {
+ return CONSTRUCTOR_CACHE.size();
+ }
+
}
Added:
lucene/hadoop/trunk/src/test/org/apache/hadoop/util/TestReflectionUtils.java
URL:
http://svn.apache.org/viewvc/lucene/hadoop/trunk/src/test/org/apache/hadoop/util/TestReflectionUtils.java?view=auto&rev=510188
==============================================================================
---
lucene/hadoop/trunk/src/test/org/apache/hadoop/util/TestReflectionUtils.java
(added)
+++
lucene/hadoop/trunk/src/test/org/apache/hadoop/util/TestReflectionUtils.java
Wed Feb 21 12:32:51 2007
@@ -0,0 +1,91 @@
+package org.apache.hadoop.util;
+
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.HashMap;
+
+import junit.framework.TestCase;
+
+public class TestReflectionUtils extends TestCase {
+
+ private static Class toConstruct[] = { String.class,
TestReflectionUtils.class, HashMap.class };
+ private Throwable failure = null;
+
+ public void setUp() {
+ ReflectionUtils.clearCache();
+ }
+
+ public void testCache() throws Exception {
+ assertEquals(0, cacheSize());
+ doTestCache();
+ assertEquals(toConstruct.length, cacheSize());
+ ReflectionUtils.clearCache();
+ assertEquals(0, cacheSize());
+ }
+
+
+ private void doTestCache() {
+ for (int i=0; i<toConstruct.length; i++) {
+ Class cl = toConstruct[i];
+ Object x = ReflectionUtils.newInstance(cl, null);
+ Object y = ReflectionUtils.newInstance(cl, null);
+ assertEquals(cl, x.getClass());
+ assertEquals(cl, y.getClass());
+ }
+ }
+
+ public void testThreadSafe() throws Exception {
+ Thread[] th = new Thread[32];
+ for (int i=0; i<th.length; i++) {
+ th[i] = new Thread() {
+ public void run() {
+ try {
+ doTestCache();
+ } catch (Throwable t) {
+ failure = t;
+ }
+ }
+ };
+ th[i].start();
+ }
+ for (int i=0; i<th.length; i++) {
+ th[i].join();
+ }
+ if (failure != null) {
+ failure.printStackTrace();
+ fail(failure.getMessage());
+ }
+ }
+
+ private int cacheSize() throws Exception {
+ return ReflectionUtils.getCacheSize();
+ }
+
+ public void testCantCreate() {
+ try {
+ ReflectionUtils.newInstance(NoDefaultCtor.class, null);
+ fail("invalid call should fail");
+ } catch (RuntimeException rte) {
+ assertEquals(NoSuchMethodException.class, rte.getCause().getClass());
+ }
+ }
+
+ public void testCacheDoesntLeak() throws Exception {
+ int iterations=9999; // very fast, but a bit less reliable - bigger
numbers force GC
+ for (int i=0; i<iterations; i++) {
+ URLClassLoader loader = new URLClassLoader(new URL[0],
getClass().getClassLoader());
+ Class cl =
Class.forName("org.apache.hadoop.util.TestReflectionUtils$LoadedInChild",
false, loader);
+ Object o = ReflectionUtils.newInstance(cl, null);
+ assertEquals(cl, o.getClass());
+ }
+ System.gc();
+ assertTrue(cacheSize()+" too big", cacheSize()<iterations);
+ }
+
+ private static class LoadedInChild {
+ }
+
+ public static class NoDefaultCtor {
+ public NoDefaultCtor(int x) {}
+ }
+}
