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Initial push. · Viewtiful/JavaPerformanceTuning@f13f3b0 · GitHub

Initial push. · Viewtiful/JavaPerformanceTuning@f13f3b0 · GitHub
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Commit f13f3b0

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Scott Oaks
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Initial push.
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‎ClassLoading/README‎

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To build:
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ant
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To run:
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java <jvmargs> -jar jars/classloading.jar jarfile nThreads useLargeStack
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jarfile -- All classes from this jar file will be loaded in the customer
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class loader
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nThreads -- Number of threads to execute simultaneously
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useLargeStack -- If true, then the lookup will be performed from a
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call stack of 40 entries
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In general, the examples leverage the modules from glassfish, but any
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large set of jar files and classes can be used.
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Notes on Examples:
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Example 12-2
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java -jar jars/classloading.jar /path_to/guava.jar N false
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where N varies from 1 to 8
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Example 12-3
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java -jar jars/classloading.jar /path_to/guava.jar N false
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where N varies from 1 to 8
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and where the CLASSPATH contains all jar files from glassfish
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(266 entries)

‎ClassLoading/build.xml‎

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<?xml version="1.0"?>
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<project name="ClassLoading" default="jar">
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<target name="init">
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<mkdir dir="classes"/>
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<mkdir dir="jars"/>
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</target>
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<target name="compile" depends="init">
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<property environment="env"/>
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<javac includeantruntime="false" srcdir="src"
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debug="true" destdir="classes">
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</javac>
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</target>
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<target name="jar" depends="compile">
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<jar jarfile="jars/classloading.jar">
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<manifest>
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<attribute name="Main-Class" value="net.sdo.ClassLoaderTest"/>
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</manifest>
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<fileset dir="classes" includes="**/*.class"/>
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</jar>
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</target>
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<target name="clean">
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<delete>
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<fileset dir="classes"/>
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<fileset dir="jars"/>
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</delete>
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</target>
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</project>

‎ClassLoading/src/net/sdo/ClassLoaderTest.java‎

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/*
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* Copyright (c) 2013,2014 Scott Oaks. All rights reserved.
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*/
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package net.sdo;
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import java.io.File;
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import java.io.IOException;
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import java.net.MalformedURLException;
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import java.net.URL;
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import java.net.URLClassLoader;
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import java.util.ArrayList;
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import java.util.Enumeration;
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import java.util.concurrent.LinkedBlockingQueue;
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import java.util.concurrent.atomic.AtomicLong;
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import java.util.zip.ZipEntry;
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import java.util.zip.ZipException;
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import java.util.zip.ZipFile;
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public class ClassLoaderTest implements Runnable {
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private static String[] classNames;
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private static AtomicLong time = new AtomicLong();
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private static URL[] urls;
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private static URLClassLoader ucl;
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private static boolean increaseStackDepth = false;
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private static void loadClasses(String[] classNames, int count, ClassLoader cl) throws ClassNotFoundException {
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for (int i = 0; i < count; i++) {
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String name = classNames[i];
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cl.loadClass(name);
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}
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}
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private static void initializeFromJar(String fileName) throws ZipException, IOException {
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ZipFile zf = new ZipFile(new File(fileName));
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Enumeration e = zf.entries();
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ArrayList<String> al = new ArrayList<String>();
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while (e.hasMoreElements()) {
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ZipEntry ze = (ZipEntry) e.nextElement();
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String s = ze.getName();
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if (s.endsWith(".class")) {
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al.add(s);
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}
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}
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String[] names = al.toArray(new String[al.size()]);
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classNames = new String[names.length];
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for (int i = 0; i < names.length; i++) {
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classNames[i] = names[i].substring(0, names[i].length() - 6).replaceAll("/", ".");
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}
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}
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public void a1() { a2(); }
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public void a2() { a3(); }
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public void a3() { a4(); }
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public void a4() { a5(); }
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public void a5() { a6(); }
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public void a6() { a7(); }
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public void a7() { a8(); }
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public void a8() { a9(); }
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public void a9() { a10(); }
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public void a10() { a11(); }
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public void a11() { a12(); }
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public void a12() { a13(); }
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public void a13() { a14(); }
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public void a14() { a15(); }
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public void a15() { a16(); }
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public void a16() { a17(); }
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public void a17() { a18(); }
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public void a18() { a19(); }
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public void a19() { a20(); }
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public void a20() { a21(); }
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public void a21() { a22(); }
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public void a22() { a23(); }
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public void a23() { a24(); }
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public void a24() { a25(); }
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public void a25() { a26(); }
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public void a26() { a27(); }
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public void a27() { a28(); }
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public void a28() { a29(); }
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public void a29() { a30(); }
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public void a30() { a31(); }
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public void a31() { a32(); }
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public void a32() { a33(); }
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public void a33() { a34(); }
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public void a34() { a35(); }
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public void a35() { a36(); }
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public void a36() { a37(); }
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public void a37() { a38(); }
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public void a38() { a39(); }
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public void a39() { a40(); }
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public void a40() {
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try {
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loadClasses(classNames, classNames.length, new URLClassLoader(urls));
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} catch (ClassNotFoundException ex) {
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System.err.println("Can't define class ");
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ex.printStackTrace();
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System.exit(-1);
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}
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}
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public void run() {
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try {
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if (increaseStackDepth) {
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a1();
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}
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else {
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loadClasses(classNames, classNames.length, new URLClassLoader(urls));
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}
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} catch (Exception e) {
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System.err.println("Can't define class ");
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e.printStackTrace();
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System.exit(-1);
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}
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}
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public static void main(String[] args) throws MalformedURLException, ClassNotFoundException, ZipException, IOException {
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initializeFromJar(args[0]);
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int nThreads = Integer.parseInt(args[1]);
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increaseStackDepth = Boolean.parseBoolean(args[2]);
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urls = new URL[]{new File(args[0]).toURL()};
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for (int i = 0; i < 10; i++) {
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ucl = new URLClassLoader(urls);
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loadClasses(classNames, classNames.length, ucl);
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}
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LinkedBlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>();
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PausingThreadPoolExecutor tpe = new PausingThreadPoolExecutor(nThreads, queue);
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tpe.prestartAllCoreThreads();
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for (int j = 0; j < 100; j++) {
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tpe.pause();
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ucl = new URLClassLoader(urls);
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for (int i = 0; i < nThreads; i++) {
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tpe.addTask(new ClassLoaderTest());
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}
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long then = System.currentTimeMillis();
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tpe.resume();
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long now = System.currentTimeMillis();
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time.getAndAdd(now - then);
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}
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tpe.shutdown();
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System.out.println("Threads: " + nThreads + ", Classes: " + classNames.length + ", Time: " + time);
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}
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}

‎ClassLoading/src/net/sdo/PausingThreadPoolExecutor.java‎

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/*
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* Copyright (c) 2013,2014 Scott Oaks. All rights reserved.
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*/
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package net.sdo;
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import java.util.concurrent.BlockingQueue;
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import java.util.concurrent.CountDownLatch;
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import java.util.concurrent.ThreadPoolExecutor;
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import java.util.concurrent.TimeUnit;
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import java.util.concurrent.locks.Condition;
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import java.util.concurrent.locks.ReentrantLock;
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public class PausingThreadPoolExecutor extends ThreadPoolExecutor {
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private boolean isPaused;
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private ReentrantLock pauseLock = new ReentrantLock();
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private Condition unpaused = pauseLock.newCondition();
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private CountDownLatch latch;
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private BlockingQueue<Runnable> queue;
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private int latchCount;
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public PausingThreadPoolExecutor(int nThreads, BlockingQueue<Runnable> queue) {
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super(nThreads, nThreads, Long.MAX_VALUE, TimeUnit.DAYS, queue);
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this.queue = queue;
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}
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@Override
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protected void beforeExecute(Thread t, Runnable r) {
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super.beforeExecute(t, r);
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pauseLock.lock();
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try {
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while (isPaused) {
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unpaused.await();
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}
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} catch (InterruptedException ie) {
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t.interrupt();
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} finally {
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pauseLock.unlock();
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}
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}
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public void addTask(Runnable r) {
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latchCount++;
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queue.add(r);
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}
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@Override
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protected void afterExecute(Runnable r, Throwable t) {
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latch.countDown();
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}
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public void pause() {
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pauseLock.lock();
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try {
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isPaused = true;
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} finally {
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pauseLock.unlock();
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}
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}
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public void resume() {
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pauseLock.lock();
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latch = new CountDownLatch(latchCount);
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latchCount = 0;
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try {
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isPaused = false;
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unpaused.signalAll();
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} finally {
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pauseLock.unlock();
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}
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try {
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latch.await();
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} catch (InterruptedException ex) {
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}
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}
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}

‎CountFilter/build.xml‎

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<?xml version="1.0"?>
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<project name="CountFilter" default="jar">
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<target name="init">
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<mkdir dir="classes"/>
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<mkdir dir="jars"/>
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</target>
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<target name="compile" depends="init">
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<property environment="env"/>
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<javac includeantruntime="false" srcdir="src"
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debug="true" destdir="classes">
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</javac>
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</target>
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<target name="jar" depends="compile">
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<jar jarfile="jars/countfilter.jar">
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<manifest>
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<attribute name="Main-Class" value="net.sdo.CountFilter"/>
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</manifest>
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<fileset dir="classes" includes="**/*.class"/>
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</jar>
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</target>
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<target name="clean">
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<delete>
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<fileset dir="classes"/>
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<fileset dir="jars"/>
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</delete>
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</target>
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</project>

‎CountFilter/src/net/sdo/CountFilter.java‎

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/*
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* Copyright (c) 2013,2014 Scott Oaks. All rights reserved.
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*/
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package net.sdo;
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import java.util.ArrayList;
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import java.util.Optional;
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import java.util.stream.Stream;
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public class CountFilter {
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private static boolean verbose;
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private static volatile int count = 0;
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private static long countFilter(ArrayList<String> al) {
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long then = System.currentTimeMillis();
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Stream<String> stream = al.stream();
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stream.filter(
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symbol -> symbol.charAt(0) != 'A' &&
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symbol.charAt(1) != 'A' &&
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symbol.charAt(2) != 'A' &&
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symbol.charAt(3) != 'A').
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forEach(symbol -> { count++; });
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long now = System.currentTimeMillis();
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return now - then;
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}
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private static long countIterator(ArrayList<String> al) {
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long then = System.currentTimeMillis();
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for (String symbol : al) {
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if (symbol.charAt(0) != 'A' &&
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symbol.charAt(1) != 'A' &&
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symbol.charAt(2) != 'A' &&
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symbol.charAt(3) != 'A')
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count++;
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}
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return System.currentTimeMillis() - then;
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}
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public static void main(String[] args) {
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verbose = Boolean.getBoolean("verbose");
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ArrayList<String> al = new ArrayList<>(500000);
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for (int first = (int) 'A'; first <= (int) 'Z'; first++) {
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for (int second = 'A'; second <= 'Z'; second++) {
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for (int third = 'A'; third <= 'Z'; third++) {
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for (int fourth = 'A'; fourth <= 'Z'; fourth++) {
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char[] c = new char[4];
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c[0] = (char) first;
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c[1] = (char) second;
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c[2] = (char) third;
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c[3] = (char) fourth;
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al.add(new String(c));
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}
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}
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}
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}
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System.out.println("Start");
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long time = 0;
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for (int i = 0; i < 1000; i++) {
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switch (args[0]) {
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case "Filter":
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time += countFilter(al);
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break;
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case "Iterator":
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time += countIterator(al);
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break;
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}
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}
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System.out.println("Operation took " + time + " ms for " + count);
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}
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}

‎Exception/README‎

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To build:
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ant
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To run:
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java <jvmargs> -jar jars/exception.jar numLoops pctExceptions
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Example 12-5:
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Run with 1000000 100
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Example 12-6:
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Run with 1000000 1

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