ArrayQueue

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package QueueClassPractice;

/**
 *
 * @author acer
 */
public class ArrayQueue {
    // The number of items in the queue
    int f;
    int r;
    int size;
    Object [] cir;

    public ArrayQueue(){
        f=-1;
        r=-1;
        size=0;
        cir=new Object [10];
    }

    public int size(){
        return size;
    }
// Returns true if the queue is empty
    public boolean isEmpty(){
        if(size==0 || f==-1)
            return true;
        return false;
    }
// Adds the new item on the back of the queue, throwing the
// QueueOverflowException if the queue is at maximum capacity. It
// does not throw an exception for an "unbounded" queue, which
// dynamically adjusts capacity as needed.
    public void enqueue(Object obj) throws QueueOverflowException{
        if(size==cir.length)
            throw new QueueOverflowException();
        else if(size==0){
            f=0;
            r=0;
            cir[r]=obj;
        }
        else{
            r=(r+1)%cir.length;
            cir[r]=obj;

        }
        size++;
    }
// Removes the item in the front of the queue, throwing the
// QueueUnderflowException if the queue is empty.
    public Object dequeue() throws QueueUnderflowException{
        Object val=null;
        if(size==0)
            throw new QueueUnderflowException();
        else if(f==r){
            val=cir[f];
            cir[f]=null;
            f=0;
            r=0;
        }
        else{
            val=cir[f];
            cir[f]=null;
            f=(f+1)%cir.length;
        }
        size--;
        return val;
    }
// Peeks at the item in the front of the queue, throwing
// QueueUnderflowException if the queue is empty.
    public Object peek() throws QueueUnderflowException{
        if(size==0)
            throw new QueueUnderflowException();
        return cir[f];
    }
// Returns a textual representation of items in the queue, in the
// format "[ x y z ]", where x and z are items in the front and
// back of the queue respectively.
    public String toString(){
    String str="";
    int k=f;
    for(int i=0;i<size();i++){
        str+=cir[k]+" ";
        k=(k+1)%cir.length;
    }
    return "[ "+str+" ]";
    }
// Returns an array with items in the queue, with the item in the
// front of the queue in the first slot, and back in the last slot.
    public Object[] toArray(){
        Object [] temp=new Object[size()];
        int k=f;
        for(int i=0;i<size();i++){
            temp[i]=cir[k];
            k=(k+1)%cir.length;
        }
        return temp;
    }
// Searches for the given item in the queue, returning the
// offset from the front of the queue if item is found, or -1
// otherwise.
    public int search(Object obj){
        int k=f;
        for(int i=0;i<size();i++){
            if(obj.equals(cir[k])){
                return i;
            }
            k=(k+1)%cir.length;
        }
        return -1;
    }
}