Source Code

/**
 * Defines an interface for encapsulating the behavior associated with a
 * particular state of the Context.
 * 
 * @role __State
 */
public interface State {
        void handle(String sample);}

/**
 * Defines an interface of interest to clients. Maintains an instance of a
 * ConcreteState subclass that defines the current state.
 */
public class Context {
        private State state;        public void setState(State newState) {
                this.state = newState;        }

        public void someOperation() {
                state.handle("aaa");        }

}

/**
 * Implements a behavior associated with a state of the Context.
 */
public class ConcreteState implements State {
        public void handle(String sample) {
                /* put your code for this particular state here */
        }

}

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