State Pattern with dependency injection

ClosedGateState.java

class ClosedGateState implements GateState {
    private GateState openGateState;

    public ClosedGateState() {
    }

    public void setOpenGateState(GateState openGateState) {
        this.openGateState = openGateState
    }

    public GateState enter() {
        return this;
    }

    public GateState payOK() {
        return openGateState;
    }

    public GateState payFail() {
        return this;
    }
}

Gate.java

class Gate {
    private GateState state;

    public Gate(GateState state) {
        this.state = state;
    }

    void enter() {
        this.state = this.state.enter()
    }

    void payOK() {
        this.state = this.state.payOK()
    }

    void payFail() {
        this.state = this.state.payFail()
    }
}

GateState.java

interface GateState {
    public GateState enter();
    public GateState payOK();
    public GateState payFail();
}

main.java

State closedGateState = new ClosedGateState()
State openGateState = new OpenGateState()

// inject OpenGateState instance for not creating it inside of ClosedGateState class
closedGateState.setOpenGateState(openGateState)
// inject ClosedGateState instance for not creating it inside of OpenGateState class
openGateState.setClosedGateState(closedGateState)

// starting with closed state
Gate gate = new Gate(closedGateState)

gate.payOK()
gate.enter()
//...

OpenGateState.java

class OpenGateState implements GateState {
    private GateState closedGateState;

    public OpenGateState() {
    }

    public void setClosedGateState(GateState closedGateState) {
        this.closedGateState = closedGateState
    }

    public GateState enter() {
        return closedGateState;
    }

    public GateState payOK() {
        return this;
    }

    public GateState payFail() {
        return this;
    }
}