//There is a problem with this implementation, produce and consume use the same lock. So you can't consume when you're producing, and you can't produce when you're consuming.
public class Storage implements StorageInterface{
private final int MAX_NUM = 100;
private LinkedList<Object> lists = new LinkedList<Object>();
public void produce(int num){
synchronized (lists) {
while(num+lists.size()>MAX_NUM){
try {
System.out.println("Temporarily unable to produce "+num+" tasks, the current inventory is: "+lists.size());
lists.wait();
} catch (InterruptedException e) {
e.printStackTrace ();
}
}
for(int i=0;i<num;i++){
lists.add(new Object());
System.out.println("Produced "+i+" items, the current inventory is: "+lists.size());
}
lists.notifyAll();
}
}
public void consume(int num){
synchronized (lists) {
while(lists.size()<num){
try {
System.out.println("Cannot consume "+num+" tasks temporarily, the number of remaining tasks: "+lists.size());
lists.wait();
} catch (InterruptedException e) {
e.printStackTrace ();
}
}
for(int i=0;i<lists.size();i++){
lists.remove(i);
System.out.println("Consumed "+i+" items, the number of products left: "+lists.size());
}
lists.notifyAll();
}
}
}
The second implementation: an implementation that can both consume and produce. Use BlockingQueue to implement.
public class StorageWithQueen implements StorageInterface{
private final int MAX_NUM = 100;
private final BlockingQueue<Object> blockingQueue = new LinkedBlockingQueue<>(MAX_NUM);
public void produce(int num) {
if(blockingQueue.size()==MAX_NUM){
System.out.println("Temporarily unable to produce "+num+" tasks, the current inventory is: "+blockingQueue.size());
}
for(int i=0;i<num;i++){
try {
blockingQueue.put(new Object());
System.out.println("Produced "+(i+1)+" items, the current inventory is: "+blockingQueue.size());
} catch (InterruptedException e) {
e.printStackTrace ();
}
}
}
public void consume(int num){
if(blockingQueue.size()==0){
System.out.println("Cannot consume "+num+" tasks temporarily, the current number of remaining tasks:"+blockingQueue.size());
}
for(int i=0;i<blockingQueue.size();i++){
try {
blockingQueue.take();
System.out.println("Consumed "+(i+1)+" items, the number of products left: "+blockingQueue.size());
} catch (InterruptedException e) {
e.printStackTrace ();
}
}
}
}