import java.util.Comparator;

import java.util.List;

import java.util.ArrayList;

/**

* This Comparator will invoke other Comparators as necesary in an attempt

* to sort on multiple fields from the same object.

*

* The first Comparator in the List is always invoked. The other Comparators

* are only invoked as required when the previous Comparator test returns

* an "equal" result.

*/

public class GroupComparator implements Comparator

{

private List<Comparator> comparators = new ArrayList<Comparator>();

/*

* A GroupComparator will always have at least two Comparators

*/

GroupComparator(Comparator first, Comparator second)

{

comparators.add( first );

comparators.add( second );

}

/*

* Add another Comparator to the sort mix.

*/

public void addComparator(Comparator comparator)

{

comparators.add( comparator );

}

/*

* Implement the Comparator interface

*/

@SuppressWarnings("unchecked")

public int compare(Object object1, Object object2)

{

// As long as the compare() result is equal (ie. 0),

// invoke the next Comparator

for (Comparator comparator : comparators)

{

int returnValue = comparator.compare(object1, object2);

if (returnValue != 0)

return returnValue;

}

return 0;

}

}