1: package TreePackage; 2: /** 3: An interface for an expression tree. 4: 5: @author Frank M. Carrano 6: @author Timothy M. Henry 7: @version 4.0 8: */ 9: public interface ExpressionTreeInterface 10: extends BinaryTreeInterface<String> 11: { 12: /** Computes the value of the expression in this tree. 13: @return The value of the expression. */ 14: public double evaluate(); 15: } // end ExpressionTreeInterface