Equilibrium index

Equi.java

/* http://rosettacode.org/wiki/Equilibrium_index
* Assume the sum of zero element is equal to zero. Write a function
* that given a sequence, returns its equilibrium index (any) or -1 
* if no equilibrium indexes exist. Assume that the sequence may be very long.
*/
public class Equi {
  private int array[];
  private int index;

  public Equi(int array[]){
    this.array = array;
  }

  public void setIndex(int index){
    this.index = index;
  }

  public boolean isEqui(){
    int prefix_sum = 0;
    int suffix_sum = 0;
    boolean result = false;

    if(index == 0){
      prefix_sum = 0;

      for(int c = index + 1; c < array.length; c++){
        suffix_sum += array[c];
      }

      if(prefix_sum == suffix_sum){
        result = true;
      } 

    } else if(index == (array.length - 1)){
      suffix_sum = 0;

      for(int c = 0; c < index; c++){
        prefix_sum += array[c];
      }

      if(prefix_sum == suffix_sum){
        result = true;
      } 
    }      
    else {
      for(int c=0;c<index;c++){
        prefix_sum += array[c];
      }

      for(int c=index+1;c<array.length;c++){
        suffix_sum += array[c];
      }

      if(prefix_sum == suffix_sum){
        result = true;
      }
    }
   
    return result;
  }
  
  public static void main(String args[]) {

  int array[] = {-7, 1, 5, 2, -4, 3, 0};
  Equi eq = new Equi(array); 

  for(int counter=0; counter<array.length; counter++){
    eq.setIndex(counter);
    if(eq.isEqui())
      System.out.println("Equilibrium index at: [" + counter + "]");
  }

  }//end main

}