what' wrong with my simple codes on reader/writer problem ,the writer thread never run
The Problem is the writer never had changes to run?
but ,why?
Thanks.
Codes:
import java.awt.*;
import java.util.concurrent.locks.*;
public class Main
{
public static void main(String[] args)
{
init();
for(int i = 0;i< readers.length;i++)
{
readers[i].start();
}
for(int j = 0;j<writers.length;j++)
{
writers[j].start();
}
}
public static void init()
{
int nr = 5;
readers = new Reader[nr];
for(int i = 0;i < nr ;i++)
{
Reader reader = new Reader(i);
readers[i] = reader;
}
//----------------------------
int nw = 3;
writers = new Writer[3];
for(int i = 0;i< nw;i++)
{
Writer writer = new Writer(i);
writers[i] = writer;
}
};
static class Reader extends Thread
{
public Reader(int num)
{
numOfReader = num;
}
public void run()
{
while(true)
{
reading();
}
}
public void reading()
{
r.lock();
try
{
System.out.println("reader "+numOfReader+" is
reading ");
this.sleep(TIMEOFWORK);
}
catch(InterruptedException e)
{
e.printStackTrace();
}
finally
{
r.unlock();
}
}
private int numOfReader;
};
static class Writer extends Thread
{
public Writer(int num)
{
numOfWriter = num;
}
public void run()
{
while(true)
{
writing(); //???
}
}
public void writing()
{
w.lock();
try
{
numOfWriter ++;
System.out.println("writer "+numOfWriter+" is writing");
this.sleep(TIMEOFWORK);
}
catch(InterruptedException e)
{
e.printStackTrace();
}
finally
{
w.unlock();
}
}
private int numOfWriter;
};
public static final ReentrantReadWriteLock rwl = new
ReentrantReadWriteLock();
public static final Lock r = rwl.readLock();
public static final Lock w = rwl.writeLock();
public static Reader[] readers;
public static Writer[] writers;
public static final int TIMEOFWORK = 2000;
}