rulesets.java.ali-concurrent.xml Maven / Gradle / Ivy

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<?xml version="1.0"?>
<ruleset name="AlibabaJavaConcurrent"
         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 http://pmd.sourceforge.net/ruleset_2_0_0.xsd">

    <rule name="ThreadPoolCreationRule"
          language="java"
          since="1.6"
          message="java.concurrent.ThreadPoolCreationRule.rule.msg"
          class="com.alibaba.p3c.pmd.lang.java.rule.concurrent.ThreadPoolCreationRule">
        <description>java.concurrent.ThreadPoolCreationRule.rule.desc</description>
        <priority>1</priority>
        <example>
            <![CDATA[
Positive example 1：
    //org.apache.commons.lang3.concurrent.BasicThreadFactory
    ScheduledExecutorService executorService = new ScheduledThreadPoolExecutor(1,
        new BasicThreadFactory.Builder().namingPattern("example-schedule-pool-%d").daemon(true).build());
       ]]>
        </example>
        <example>
            <![CDATA[
Positive example 2：
    ThreadFactory namedThreadFactory = new ThreadFactoryBuilder()
        .setNameFormat("demo-pool-%d").build();

    //Common Thread Pool
    ExecutorService pool = new ThreadPoolExecutor(5, 200,
        0L, TimeUnit.MILLISECONDS,
        new LinkedBlockingQueue<Runnable>(1024), namedThreadFactory, new ThreadPoolExecutor.AbortPolicy());

    pool.execute(()-> System.out.println(Thread.currentThread().getName()));
    pool.shutdown();//gracefully shutdown
       ]]>
        </example>
        <example>
            <![CDATA[
Positive example 3：
    <bean id="userThreadPool"
        class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
        <property name="corePoolSize" value="10" />
        <property name="maxPoolSize" value="100" />
        <property name="queueCapacity" value="2000" />

    <property name="threadFactory" value= threadFactory />
        <property name="rejectedExecutionHandler">
            <ref local="rejectedExecutionHandler" />
        </property>
    </bean>
    //in code
    userThreadPool.execute(thread);
       ]]>
        </example>
    </rule>
    <rule name="AvoidUseTimerRule"
          language="java"
          since="1.6"
          message="java.concurrent.AvoidUseTimerRule.rule.msg"
          class="com.alibaba.p3c.pmd.lang.java.rule.concurrent.AvoidUseTimerRule">
        <priority>1</priority>
        <example>
            <![CDATA[
    //org.apache.commons.lang3.concurrent.BasicThreadFactory
    ScheduledExecutorService executorService = new ScheduledThreadPoolExecutor(1,
        new BasicThreadFactory.Builder().namingPattern("example-schedule-pool-%d").daemon(true).build());
    executorService.scheduleAtFixedRate(new Runnable() {
        @Override
        public void run() {
            //do something
        }
    },initialDelay,period, TimeUnit.HOURS);
       ]]>
        </example>
    </rule>
    <rule name="AvoidManuallyCreateThreadRule"
          language="java"
          since="1.6"
          message="java.concurrent.AvoidManuallyCreateThreadRule.rule.msg"
          dfa="true"
          class="com.alibaba.p3c.pmd.lang.java.rule.concurrent.AvoidManuallyCreateThreadRule">
        <description>java.concurrent.AvoidManuallyCreateThreadRule.rule.desc</description>
        <priority>2</priority>
        <example>
            <![CDATA[
    ThreadFactory namedThreadFactory = new ThreadFactoryBuilder()
        .setNameFormat("demo-pool-%d").build();
    ExecutorService singleThreadPool = new ThreadPoolExecutor(1, 1,
        0L, TimeUnit.MILLISECONDS,
        new LinkedBlockingQueue<Runnable>(1024), namedThreadFactory, new ThreadPoolExecutor.AbortPolicy());

    singleThreadPool.execute(()-> System.out.println(Thread.currentThread().getName()));
    singleThreadPool.shutdown();
    ]]>
        </example>
    </rule>
    <rule name="ThreadShouldSetNameRule"
          language="java"
          since="1.6"
          message="java.concurrent.ThreadShouldSetNameRule.rule.msg"
          dfa="true"
          class="com.alibaba.p3c.pmd.lang.java.rule.concurrent.ThreadShouldSetNameRule">
        <priority>2</priority>
        <example>
            <![CDATA[
    ThreadFactory namedThreadFactory = new ThreadFactoryBuilder()
        .setNameFormat("demo-pool-%d").build();
    ExecutorService singleThreadPool = new ThreadPoolExecutor(1, 1,
        0L, TimeUnit.MILLISECONDS,
        new LinkedBlockingQueue<Runnable>(1024), namedThreadFactory, new ThreadPoolExecutor.AbortPolicy());

    singleThreadPool.execute(()-> System.out.println(Thread.currentThread().getName()));
    singleThreadPool.shutdown();
    ]]>
        </example>
        <example>
            <![CDATA[
    public class TimerTaskThread extends Thread {
        public TimerTaskThread(){
        super.setName("TimerTaskThread"); …
    }
       ]]>
        </example>
    </rule>
    <rule name="AvoidCallStaticSimpleDateFormatRule"
          language="java"
          since="1.6"
          message="java.concurrent.AvoidCallStaticSimpleDateFormatRule.rule.msg"
          dfa="true"
          class="com.alibaba.p3c.pmd.lang.java.rule.concurrent.AvoidCallStaticSimpleDateFormatRule">
        <description>java.concurrent.AvoidCallStaticSimpleDateFormatRule.rule.desc</description>

        <example>
            <![CDATA[
Positive example 1：
    private static final String FORMAT = "yyyy-MM-dd HH:mm:ss";
    public String getFormat(Date date){
        SimpleDateFormat dateFormat = new SimpleDateFormat(FORMAT);
        return sdf.format(date);
    }
        ]]>
        </example>
        <example>
            <![CDATA[
Positive example 2：
    private static final SimpleDateFormat SIMPLE_DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    public void getFormat(){
        synchronized (sdf){
        sdf.format(new Date());
        ….;
    }
        ]]>
        </example>
        <example>
            <![CDATA[
Positive example 3：
    private static final ThreadLocal<DateFormat> DATE_FORMATTER = new ThreadLocal<DateFormat>() {
        @Override
        protected DateFormat initialValue() {
            return new SimpleDateFormat("yyyy-MM-dd");
        }
    };
        ]]>
        </example>
        <priority>2</priority>
    </rule>

    <rule name="ThreadLocalShouldRemoveRule"
          language="java"
          since="1.6"
          message="java.concurrent.ThreadLocalShouldRemoveRule.rule.msg"
          dfa="true"
          class="com.alibaba.p3c.pmd.lang.java.rule.concurrent.ThreadLocalShouldRemoveRule">
        <priority>2</priority>
        <example>
            <![CDATA[
    /**
     * @author caikang
     * @date 2017/04/07
     */
    public class UserHolder {
        private static final ThreadLocal<User> userThreadLocal = new ThreadLocal<User>();

        public static void set(User user){
            userThreadLocal.set(user);
        }

        public static User get(){
            return userThreadLocal.get();
        }

        public static void remove(){
            userThreadLocal.remove();
        }
    }

    /**
     * @author caikang
     * @date 2017/04/07
     */
    public class UserInterceptor extends HandlerInterceptorAdapter {
        @Override
        public boolean preHandle(HttpServletRequest request,
            HttpServletResponse response, Object handler) throws Exception {
            UserHolder.set(new User());
            return true;
        }

        @Override
        public void afterCompletion(HttpServletRequest request,
            HttpServletResponse response, Object handler, Exception ex) throws Exception {
            UserHolder.remove();
        }
    }
        ]]>
        </example>
    </rule>
    <rule name="AvoidConcurrentCompetitionRandomRule"
          language="java"
          since="1.6"
          message="java.concurrent.AvoidConcurrentCompetitionRandomRule.rule.msg"
          dfa="true"
          class="com.alibaba.p3c.pmd.lang.java.rule.concurrent.AvoidConcurrentCompetitionRandomRule">
        <priority>3</priority>
        <example>
            <![CDATA[
Positive example 1：
    /**
     * @author caikang
     * @date 2017/04/07
     */
    public class RandomInThread extends Thread {
        private Random random = new Random();

        @Override
        public void run() {
            long t = random.nextLong();
        }
    }
        ]]>
        </example>
        <example>
            <![CDATA[
Positive example 2：
    /**
     * @author caikang
     * @date 2017/04/07
     */
    public class RandomInThread extends Thread {
        private Random random = ThreadLocalRandom.current();

        @Override
        public void run() {
            long t = random.nextLong();
        }
    }
        ]]>
        </example>
    </rule>
    <rule name="CountDownShouldInFinallyRule"
          language="java"
          since="1.6"
          message="java.concurrent.CountDownShouldInFinallyRule.rule.msg"
          dfa="true"
          class="com.alibaba.p3c.pmd.lang.java.rule.concurrent.CountDownShouldInFinallyRule">
        <description>java.concurrent.CountDownShouldInFinallyRule.rule.desc</description>
        <priority>3</priority>
        <example>
            <![CDATA[
    /**
     * @author caikang
     * @date 2017/04/07
     */
    public class CountDownExample {
        public void operate(CountDownLatch countDownLatch){
            try{
                System.out.println("business logic");
            }catch (RuntimeException e){
                // do something
            }finally {
                countDownLatch.countDown();
            }
        }
    }
        ]]>
        </example>
    </rule>
</ruleset>