操作系统读者写者问题算法.doc

读者优先public class MYRW public static void main(String args)CubbyHole c=new CubbyHole();Reader r1=new Reader(1,c);Reader r2=new Reader(2,c);Reader r3=new Reader(3,c);Reader r4=new Reader(4,c);Writer w1=new Writer(1,c);Writer w2=new Writer(2,c);r1.start();tryThread.sleep(1000);r2.start();Thread.sleep(1000);w1.start();Thread.sleep(1000);r3.start();Thread.sleep(1000);w2.start();Thread.sleep(1000);r4.start();Thread.sleep(1000);catch(Exception e)class CubbyHoleint readCount,writeCount;boolean sourceReading=false,sourceWriting=false;public CubbyHole()readCount=0;writeCount=0;sourceReading=false;sourceWriting=false;public synchronized int startRead()while(writeCount0&readCount=0)System.out.println(reader is waiting);try wait(); catch (InterruptedException e) / TODO Auto-generated catch blocke.printStackTrace();readCount+;if(readCount0)sourceReading=true;return readCount;public synchronized int endRead()readCount-;if(readCount=0)sourceReading=false;notifyAll();/System.out.println(one reader finished reading);return readCount;public synchronized void startWrite()writeCount+;while(sourceReading=true|sourceWriting=true)System.out.println(Writer is waiting);try wait(); catch (InterruptedException e) / TODO Auto-generated catch blocke.printStackTrace();sourceWriting=true;public synchronized void endWrite()writeCount-;sourceWriting=false;/System.out.println(one writer finished writing);notifyAll();class Reader extends ThreadCubbyHole c;int rNumber;public Reader(int r,CubbyHole c)rNumber=r;this.c=c;public void run()int x;if(true)/System.out.println(读线程+rNumber+正在休眠);try /Thread.sleep(3000);System.out.println(读线程+rNumber+申请读);x=c.startRead();/Thread.sleep(3000);System.out.println(读线程+rNumber+正在读,共有+c.readCount+个线程正在读);Thread.sleep(2500);System.out.println(x=c.endRead()+读线程+rNumber+已经完成读操作,h还有+x+个线程在读); catch (InterruptedException e) / TODO Auto-generated catch blocke.printStackTrace();class Writer extends Threadint wNumber;CubbyHole c;public Writer(int w,CubbyHole c)wNumber=w;this.c=c;public void run()int x;if(true)/System.out.println(写线程+wNumber+正在休眠);try /Thread.sleep(3000);System.out.println(写线程+wNumber+申请写);c.startWrite();/Thread.sleep(2500);System.out.println(写线程+wNumber+正在写);Thread.sleep(2500);c.endWrite();System.out.println(写线程+wNumber+已经完成写操作); catch (InterruptedException e) / TODO Auto-generated catch blocke.printStackTrace();写者优先public class MYRW public static void main(String args)CubbyHole c=new CubbyHole();Reader r1=new Reader(1,c);Reader r2=new Reader(2,c);Reader r3=new Reader(3,c);Reader r4=new Reader(4,c);Writer w1=new Writer(1,c);Writer w2=new Writer(2,c);r1.start();tryThread.sleep(1000);r2.start();Thread.sleep(1000);w1.start();Thread.sleep(1000);r3.start();Thread.sleep(1000);w2.start();Thread.sleep(1000);r4.start();Thread.sleep(1000);catch(Exception e)class CubbyHoleint readCount,writeCount;boolean sourceReading=false,sourceWriting=false;public CubbyHole()readCount=0;writeCount=0;sourceReading=false;sourceWriting=false;public synchronized int startRead()while(writeCount0)System.out.println(reader is waiting);try wait(); catch (InterruptedException e) / TODO Auto-generated catch blocke.printStackTrace();readCount+;if(readCount0)sourceReading=true;return readCount;public synchronized int endRead()readCount-;if(readCount=0)sourceReading=false;notifyAll();/System.out.println(one reader finished reading);return readCount;public synchronized void startWrite()writeCount+;while(sourceReading=true|sourceWriting=true)System.out.println(Writer is waiting);try wait(); catch (InterruptedException e) / TODO Auto-generated catch blocke.printStackTrace();sourceWriting=true;public synchronized void endWrite()writeCount-;sourceWriting=false;/System.out.println(one writer finished writing);notifyAll();class Reader extends ThreadCubbyHole c;int rNumber;public Reader(int r,CubbyHole c)rNumber=r;this.c=c;public void run()int x;if(true)/System.out.println(读线程+rNumber+正在休眠);try /Thread.sleep(3000);System.out.println(读线程+rNumber+申请读);x=c.startRead();/Thread.sleep(3000);System.out.println(读线程+rNumber+正在读,共有+c.readCount+个线程正在读);Thread.sleep(2500);System.out.println(x=c.endRead()+读线程+rNumber+已经完成读操作,h还有+x+个线程在读); catch (InterruptedException e) / TODO Auto-generated catch blocke.printStackTrace();class Writer extends Threadint wNumber;CubbyHole c;public Writer(int w,CubbyHole c)wNumber=w;this.c=c;public void run()int x;if(true)/System.out.println(写线程+wNumber+正在休眠);try /Thread.sleep(3000);System.out.println(写线程+wNumbe