最近在学习java的并发包编程，写了一段代码，模仿原来测试ArrayList非安全代码来测试java.util.Stack是否是线程安全的。代码如下：
[code="java"]
package concurrent.lock.alg;
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
public class StackTest {
private static final int ELEMENT_NUM = 51180;
public static void main(String[] ben){
ExecutorService exec = Executors.newCachedThreadPool();
final Stack stackStr = new Stack();
for(int i=0;i<ELEMENT_NUM;++i){
exec.submit(new StackInsTask(stackStr));
}
exec.shutdown();
try{
exec.awaitTermination(500, TimeUnit.SECONDS);
}catch(InterruptedException e){
e.printStackTrace();
}
List<String> testList = new ArrayList<String>();
while(!stackStr.empty()){
String dd = String.valueOf(stackStr.pop());
//System.out.println(dd);
testList.add(String.valueOf(dd));
}
//System.out.println(testList.size());
for(int i=1;i<=ELEMENT_NUM;++i){
if(!testList.contains(String.valueOf(i))){
System.out.println("didn't find"+i);
}
}
}
}
class StackInsTask implements Runnable {
public static AtomicInteger count = new AtomicInteger();
Stack stack;
public StackInsTask(Stack s) {
stack = s;
}
public void run() {
stack.push(count.incrementAndGet());
}
}
[/code]
51180个线程同时启动，如果stack非安全，那么stack.push(count.incrementAndGet())插入的可能是同一个值。那么在：
[code="java"]
for(int i=1;i<=ELEMENT_NUM;++i){
if(!testList.contains(String.valueOf(i))){
System.out.println("didn't find"+i);
}
}
[/code]
[b]就会输出找不到的值，可是测试了几把发现好像是安全的,由于jdk也没说明stack是否是线程安全的，暂时没看源码，所以好奇来问下。顺便问下，eclipse看jdk源码需要下载些什么，这里偷个懒嘿嘿~[/b]
---------------------------------分割线，以下代码是证明ArrayList非安全的代码--------------------------------------
[code="java"]
package com.concurrent.Amino.List;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
public class CommonListTest {
private static final int ELEMENT_NUM = 28000;
public static void main(String[] argvs) {
ExecutorService exec = Executors.newCachedThreadPool();
// final List listStr = new LockFreeList();
final List listStr = new ArrayList();
for (int i = 0; i < ELEMENT_NUM; ++i) {
exec.submit(new ListInsTask(listStr));
}
exec.shutdown();
try {
exec.awaitTermination(500, TimeUnit.SECONDS);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Size of list is" + listStr.size());
for (int i = 1; i <= ELEMENT_NUM; ++i) {
if (!listStr.contains(i)) {
System.out.println("didn't find " + i);
}
}
System.out.println(ListInsTask.count.longValue());
}
}
class ListInsTask implements Runnable {
public static AtomicInteger count = new AtomicInteger();
List list;
public ListInsTask(List l) {
list = l;
}
public void run() {
if (list.add(count.incrementAndGet())) {
//System.out.println("List Size = " + list.size());
} else {
System.out.println("did not insert" + count.get());
}
}
}
[/code]
