/*****************************************************************************/ /* */ /* Producer and Consumer Program */ /* Graphical Version Allowing Multiple Instances */ /* */ /* January 1999, Toshimi Minoura */ /* October 1999, Jacob Lundberg */ /* */ /*****************************************************************************/ // A producer thread places jobs in a bounded-buffer, // and these jobs are retrieved by a consumer thread. import java.awt.*; import java.util.*; class BoundedBufferG { static final int BufferSize = 3; // constant defining size of this buffer private Object data[]; // storage for data queued private int headIdx; // index to head of queued data private int tailIdx; // index to tail of queued data private int nElements; // number of elements in this buffer public BoundedBufferG() { // constructor reset(); } public synchronized void reset() { data = new Object[BufferSize]; // create array for Objects for (int i = 0; i < BufferSize; i++) { data[i] = null; // initially, no element } headIdx = 0; // position of data[0] tailIdx = BufferSize - 1; // position preceding data[0] nElements = 0; // initially, no elements } public synchronized void enqueue(String name, Object x) { while (nElements == BufferSize) { // buffer is full // System.out.println("Thread " + name + " will be blocked"); try { wait(); } // block calling Thread catch (java.lang.InterruptedException e) { }; } if (++tailIdx == BufferSize) tailIdx = 0; // end of buffer, wrap around // System.out.println("Object " + x + " enqueued in data[" + tailIdx + "]" data[tailIdx] = x; // store argument object nElements++; // one element added notify(); // activate blocked consumer } public synchronized Object dequeue(String name) { while (nElements == 0) { // buffer is empty // System.out.println("Thread " + name + " will be blocked"); try { wait(); } // block calling Thread catch (java.lang.InterruptedException e) { }; } Object temp = data[headIdx]; // object to be returned data[headIdx] = null; // no object in this slot // System.out.println("Object " + temp + " dequeued from data[" // + headIdx + "]"); if (++headIdx == BufferSize) headIdx = 0; // wrap around nElements--; // one element removed notify(); // activate blocked producer return temp; } public synchronized void dataPrint() { // print stack content System.out.print("BoundedBuffer: headIdx = " + headIdx + ", tailIdx = " + tailIdx + ", data = "); for (int i = 0; i < BufferSize; i++) { System.out.print(data[i]); // print every value in data[] if (i < BufferSize - 1) System.out.print(", "); } System.out.println(""); } public void drawRightArrow(Graphics g, int x1, int y1, int x2) { Polygon poly = new Polygon(); // arrow from (x1, y1) to (x2, y1) poly.addPoint(x1, y1 - 2); poly.addPoint(x1, y1 + 2); poly.addPoint(x2 - 6, y1 + 2); poly.addPoint(x2 - 6, y1 + 6); poly.addPoint(x2, y1); // tip of right arrow poly.addPoint(x2 - 6, y1 - 6); poly.addPoint(x2 - 6, y1 - 2); g.fillPolygon(poly); // draw arrow } static final Color BoxColor = new Color(150, 0, 0); // for box outline static final Color EmptyBox = new Color(0, 150, 0); // for empty box static final Color FilledBox = new Color(100, 255, 0); // for filled box static final Color EmptyLetter = new Color(255,255, 255); // for null box static final Color FullLetter = new Color(100, 100, 0); // for value in box static final Color RightArrowColor = new Color(0, 0, 200); static final Color ArrowLabel = new Color(0, 0, 200); // Font f = new Font("TimesRoman", Font.BOLD, 18); public synchronized void paint(Graphics g) { int x1 = 280; // left position for queue elements int y = 80; // top position of queue elements int Width = 60; // width of queue element int Height = 35; // height of queue element int PointerXLoc = x1 - Width * 2 / 3; // System.out.println("BoundedBufferG.paint() called"); g.setFont(f); // set font for letters if (headIdx == tailIdx) { int y2 = y + headIdx * Height; // y position of arrow g.setColor (FullLetter); // set letter color g.drawString("head & tail", x1 - Width * 8 / 3, y2 + Height / 2 + 5); g.setColor(RightArrowColor); // set right arrow color drawRightArrow(g, PointerXLoc, y2 + Height / 2, // draw head pointer x1 - 2); } else { int y2 = y + headIdx * Height; // y position of arrow g.setColor (FullLetter); // set letter color g.drawString("head", x1 - Width * 4 / 3 - 15, y2 + Height / 2 + 5); g.setColor(RightArrowColor); // set right arrow color drawRightArrow(g, PointerXLoc, y2 + Height / 2, // draw head pointer x1 - 2); int y3 = y + tailIdx * Height; // y position of arrow g.setColor (FullLetter) ; // set letter color g.drawString("tail", x1 - Width * 4 / 3, y3 + Height / 2 + 5); g.setColor(RightArrowColor); // set right arrow color drawRightArrow(g, PointerXLoc, y3 + Height / 2, // draw tail pointer x1 - 2); } for (int i = 0; i < data.length; i ++) { // draw queue elements if (data[i] == null) { // is queue element empty? g.setColor(EmptyBox); // yes, use empty box color g.fillRect(x1, y, Width, Height); // fill box g.setColor(EmptyLetter); // set light letter color } else { // queue element exists g.setColor(FilledBox); // set clor for box with element g.fillRect(x1, y, Width, Height); // draw box g.setColor(FullLetter); // set dark letter color } if (data[i] == null) { // no queue element? g.drawString("null", x1 + 12, y + Height / 2 + 5); // indicate null } else { g.drawString(String.valueOf(data[i]), x1 + 15, y + Height / 2 + 5); } g.setColor(BoxColor); // set box outline color g.drawRect(x1, y, Width - 1, Height); // draw box outline y += Height; // update y position of next array element } } } class ProducerG extends Thread { static final int NJobs = 20; // number of jobs produced String name; // name of this producer BoundedBufferG queue; // queue this producer is connected to StepTestCanvas canvas; String currentJob = null; // ID of current job being produced final int MinTime = 3000; // minimum time required to prepare a job final int MaxTime = 12000; // maximum time required to prepare a job final int DelayTime = 1000; // interval for updating work progress int totalTime; // time needed to process current job int workTime; // time spent so far int yloc; // y-location of a given producer instance public ProducerG(String name, BoundedBufferG queue, StepTestCanvas canvas, int y1) { this.name = name; // copy argument this.queue = queue; // copy argument this.canvas = canvas; // copy argument this.yloc = y1; // copy argument } void reset() { currentJob = null; } static final Color BoxColor = new Color(150, 0, 0); // for box outline static final Color InsideColor = new Color(200, 200, 255); // for inside box static final Color DoneColor = new Color(0, 0, 255); // for work done static final Color LetterColor = new Color(0, 0, 255); // idle synchronized void paint(Graphics g) { // System.out.println("ProducerG.paint() called"); int x1 = 50; // left position for job progress indicator int y1 = yloc; // top position of job progress indicator int MaxWidth = 80; // maximum width of job progress indicator int width; int Height = 25; // height of job progress indicator if (y1 <= 0) y1 = 100; // default for sanity and convenience g.setColor(Color.black); g.drawString("Producer", x1, y1 - 15); if (currentJob == null) { return; } width = MaxWidth * totalTime / MaxTime; int doneWidth = width * workTime / totalTime; // System.out.println("ProducerG.paint(): doneWidth = " + doneWidth); if (workTime < totalTime) { // is work in progress? g.setColor(InsideColor); // set box inside color g.fillRect(x1, y1, width , Height); // inside background g.setColor(DoneColor); // set work done color g.fillRect(x1, y1, doneWidth, Height); // work done g.setColor(BoxColor); // set box outline color g.drawRect(x1, y1, width - 1, Height - 1); // draw box outline } else { // producer being blocked g.setColor(LetterColor); g.drawString("Producer Blocked", x1, y1 + Height /2 +5); } g.setColor(Color.black); g.drawString("Job "+ currentJob, x1, y1 + Height + 22); } public void run() { // If the whole method is synchronized, when queue.enqueue() // is blocked, paint() cannot be executed. System.out.println("Producer " + name + " started"); // queue.dataPrint(); // print queue content for (int i = 1; i <= NJobs; i++) { synchronized(this) { totalTime = (int) (Math.random() * (MaxTime - MinTime) + MinTime); if (i > NJobs / 2) { // make producer slow for second-half period totalTime = totalTime * 2; } currentJob = name + '.' + i; // construct job name System.out.println("Producer " + name + " will create " + currentJob + " in " + totalTime + " msecs."); canvas.repaintMsg("Producer " + name + " will create " + currentJob + " in " + totalTime + " msecs."); for (workTime = 0; workTime < totalTime; ) { try { wait(DelayTime);} // delay execution catch (java.lang.InterruptedException e) { }; workTime += DelayTime; canvas.repaint(); } } queue.enqueue(name, currentJob); // insert element into queue synchronized(this) { currentJob = null; } // queue.dataPrint(); // print queue content canvas.repaint(); // update screen } System.out.println("Producer " + name + " completed"); } } class ConsumerG extends Thread { static final int NJobs = 20; // number of jobs consumed String name; // name of this consumer BoundedBufferG queue; // queue this consumer is connected to StepTestCanvas canvas; String currentJob = null; // job ID of current job final int MinTime = 3000; // minimum time required to consume a job final int MaxTime = 12000; // maximum time required to consume a job final int DelayTime = 1000; // interval for updating work progress int totalTime; // time required to consume current job int workTime; // time spent so far boolean active = false; // thread started int yloc; // y-location of a given consumer instance public ConsumerG(String name, BoundedBufferG queue, StepTestCanvas canvas, int y1) { this.name = name; // copy argument this.queue = queue; // copy argument this.canvas = canvas; // copy argument this.yloc = y1; // copy argument } void reset() { currentJob = null; active = false; // to supress "Consumer Idle" message } static final Color BoxColor = new Color(150, 0, 0); // for box outline static final Color InsideColor = new Color(200, 200, 255); // for inside box static final Color DoneColor = new Color(0, 0, 255); // for work done static final Color LetterColor = new Color(0, 0, 255); // idle synchronized void paint(Graphics g) { // System.out.println("ProducerG.paint() called"); int x1 = 400; // left position for job progress indicator int y1 = yloc; // top position of job progress indicator int MaxWidth = 80; // maximum width of job progress indicator int width; int Height = 25; // height of job progress indicator if (y1 <= 0) y1 = 100; // default for sanity and convenience g.setColor(Color.black); g.drawString("Consumer", x1, y1 - 15); if (!active) { // consumer not running return; } if (currentJob == null) { // consumer waiting for a job g.setColor(LetterColor); g.drawString("Consumer Idle", x1, y1 + Height /2 +5); return; } width = MaxWidth * totalTime / MaxTime; int doneWidth = width * workTime / totalTime; // System.out.println("ConsumerG.paint(): doneWidth = " + doneWidth); if (workTime < totalTime) { // is work in progress? g.setColor(InsideColor); // set box inside color g.fillRect(x1, y1, width , Height); // inside background g.setColor(DoneColor); // set work done color g.fillRect(x1, y1, doneWidth, Height); // work done } g.setColor(BoxColor); // set box outline color g.drawRect(x1, y1, width - 1, Height - 1); // draw box outline g.setColor(Color.black); g.drawString("Job "+ currentJob, x1, y1 + Height + 22); } public void run() { // If the whole method is synchronized, when queue.dequeue() // is blocked, paint() cannot be executed. System.out.println("Consumer " + name + " started"); active = true; // thread started for (int i = 1; i <= NJobs; i++) { currentJob = (String) queue.dequeue(name); // get next job System.out.println("Consumer " + name + " dequeued " + currentJob); // queue.dataPrint(); // print queue content synchronized(this) { totalTime = (int) (Math.random() * (MaxTime - MinTime) + MinTime); if (i < NJobs / 2) { // make consumer slow for first-half period totalTime = totalTime * 2; } System.out.println("Consumer " + name + " will be busy for " + totalTime + " msecs"); canvas.repaintMsg("Consumer " + name + " will process " + currentJob + " in " + totalTime + " msecs."); for (workTime = 0; workTime < totalTime; ) { try { wait(DelayTime);} // delay execution catch (java.lang.InterruptedException e) { }; workTime += DelayTime; canvas.repaint(); } currentJob = null; // no job being processed } canvas.repaint(); // update screen } System.out.println("Consumer " + name + " completed"); } } public class ProdConsG extends StepTestCanvas { BoundedBufferG queue = new BoundedBufferG(); ProducerG producer1; ProducerG producer2; ConsumerG consumer1; ConsumerG consumer2; Font f = new Font("TimesRoman", Font.BOLD, 18); public void paint(Graphics g) { // called when window need be redrawn // System.out.println("ProdConsG.paint() called"); g.setFont(f); // set font for letters queue.paint(g); // draw stack if (producer1 != null) producer1.paint(g); // show state of producer1 if (producer2 != null) producer2.paint(g); // show state of producer2 if (consumer1 != null) consumer1.paint(g); // show state of consumer1 if (consumer2 != null) consumer2.paint(g); // show state of consumer2 } public void runMain() { System.out.println("runMain() started"); if (producer1 != null) { producer1.stop(); producer1.reset(); } if (producer2 != null) { producer2.stop(); producer2.reset(); } if (consumer1 != null) { consumer1.stop(); consumer1.reset(); } if (consumer2 != null) { consumer2.stop(); consumer2.reset(); } queue.reset(); repaintStep("Press Step button to start some producers and consumers."); producer1 = new ProducerG("p1", queue, this, 50); producer1.start(); producer2 = new ProducerG("p2", queue, this, 175); producer2.start(); consumer1 = new ConsumerG("c1", queue, this, 50); consumer1.start(); consumer2 = new ConsumerG("c2", queue, this, 175); consumer2.start(); repaintMsg("Producers p1, p2 and consumers c1 started."); System.out.println("runMain() completed"); } public static void main(String[] args) { StepTestFrame f = new StepTestFrame("Producer and consumer", new ProdConsG(), 580, 400); f.show(); // display frame } }