TD1: Explain and fix the deadlock in exo3.

[TD_SR.git] / TD1 / exo3 / BufferCirc.java

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/**\r
 * implementation du producteur consommateur avec un buffer circulaire\r
 */\r
public class BufferCirc {\r
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	private Object[] tampon;\r
	private int taille;\r
	private int prem, der, nbObj;\r
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	public BufferCirc (int t) {\r
		taille = t;\r
		tampon = new Object[taille];\r
		prem = 0;\r
		der = 0;\r
		nbObj = 0;\r
	}\r
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	public boolean isEmpty() {\r
		return nbObj == 0;\r
	}\r
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	public boolean isFull() {\r
		return nbObj == taille;\r
	}\r
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	public synchronized void depose(Object obj) {\r
		while(isFull()) {\r
			try {\r
				System.out.println("Buffer is full: " + Thread.currentThread().getName()\r
                                    + " is waiting, size: " + nbObj);\r
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				wait();\r
			}\r
			catch (InterruptedException e) {}\r
		}\r
		nbObj++;\r
		tampon[prem] = obj;\r
		prem = (prem + 1) % taille;\r
		//System.out.println(Thread.currentThread().getName() + " a depose " + (Integer)obj);\r
		notifyAll();\r
	}\r
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	public synchronized Object preleve() {\r
		while(isEmpty()) {\r
			try {\r
				System.out.println("Buffer is empty: " + Thread.currentThread().getName()\r
                                    + " is waiting, size: " + nbObj);\r
				wait();\r
			}\r
			catch (InterruptedException e) {}\r
		}\r
		Object outObj = null;\r
		nbObj--;\r
		outObj = tampon[der];\r
		der = (der + 1) % taille;\r
		//System.out.println(Thread.currentThread().getName() + " a preleve " + (Integer)outObj);\r
		notifyAll();\r
		return outObj;\r
	}\r
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} // fin class BufferCirc\r