java.lang.ThreadGroup.checkAccess()%uA0方法确定当前运行的线程是否有权修改该线程组。
声明
以下是java.lang.ThreadGroup.checkAccess()方法的声明
public final void checkAccess()
参数
-
NA
返回值
此方法不返回任何值。
异常
-
SecurityException%uA0-- 如果当前线程不允许访问该线程组。
例子
下面的例子显示java.lang.ThreadGroup.checkAccess()方法的使用。
package com.yiibai import java.lang.* public class ThreadGroupDemo implements Runnable { public static void main(String[] args) { ThreadGroupDemo tg = new ThreadGroupDemo() tg.func() } public void func() { try { // create a parent ThreadGroup ThreadGroup pGroup = new ThreadGroup("Parent ThreadGroup") // create a child ThreadGroup for parent ThreadGroup ThreadGroup cGroup = new ThreadGroup(pGroup, "Child ThreadGroup") // create a thread Thread t1 = new Thread(pGroup, this) System.out.println("Starting " + t1.getName() + "...") t1.start() // create another thread Thread t2 = new Thread(cGroup, this) System.out.println("Starting " + t2.getName() + "...") t2.start() // checking the access for these ThreadGroups. try { pGroup.checkAccess() System.out.println(pGroup.getName() + " has access") cGroup.checkAccess() System.out.println(cGroup.getName() + " has access") } catch (SecurityException ex) { System.out.println("No access: " + ex.toString()) } // block until the other threads finish t1.join() t2.join() } catch (InterruptedException ex) { System.out.println(ex.toString()) } } // implements run() public void run() { for(int i=0i<1000i++) { i++ } System.out.println(Thread.currentThread().getName() + " finished executing") } }
让我们来编译和运行上面的程序，这将产生以下结果：
Starting Thread-0... Starting Thread-1... Parent ThreadGroup has access Child ThreadGroup has access Thread-0 finished executing Thread-1 finished executing