没有一个编程的IFS的挑战

This project contains code for a simple calculator. The challenge is to refactor the application such that it contains no conditional logic or loop structures.

SwingCalculatorNoIfs
.classpath
.project
CalculatorButton.class
CalculatorButton.java
CalculatorModel$NullOperator.class
CalculatorModel.class
CalculatorModel.java
CalculatorStrategy.class
CalculatorStrategy.java
EqualsButton.class
EqualsButton.java
GNU Public License
MinusButton.class
MinusButton.java
NumberButton.class
NumberButton.java
OperatorButton.class
OperatorButton.java
PlusButton.class
PlusButton.java
PostOperatorStrategy.class
PostOperatorStrategy.java
PreOperatorStrategy.class
PreOperatorStrategy.java
SwingCalculatorNoIfs.class
SwingCalculatorNoIfs.java