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package com.smartdevicelink.api;
import android.support.annotation.IntDef;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
public class StreamingStateMachine {
@IntDef({NONE, READY, STARTED, STOPPED, ERROR})
@Retention(RetentionPolicy.SOURCE)
public @interface StreamingState {}
public static final int NONE = 0x00, READY = 0x30, STARTED = 0x60, STOPPED = 0x90, ERROR = 0xC0;
private @StreamingState int state = NONE;
private final Object STATE_LOCK = new Object();
public StreamingStateMachine(){}
public void transitionToState(int state) {
if(state != NONE && state != READY && state != STARTED
&& state != STOPPED && state != ERROR) {
return;
}
synchronized (STATE_LOCK) {
if(isValidTransition(this.state, state)){
this.state = state;
}
}
}
public @StreamingState int getState() {
synchronized (STATE_LOCK) {
return state;
}
}
private boolean isValidTransition(int prev_state, int next_state){
if(prev_state == next_state){
return false;
}
switch (prev_state){
case NONE:
if((next_state == READY) || (next_state == ERROR)){
return true;
}
break;
case READY:
if((next_state == STARTED) || (next_state == ERROR)){
return true;
}
break;
case STARTED:
if((next_state == STOPPED) || (next_state == ERROR)){
return true;
}
break;
case STOPPED:
if((next_state == STARTED) || (next_state == NONE)){
return true;
}
break;
case ERROR:
if(next_state == NONE){
return true;
}
break;
default:
break;
}
return false;
}
}
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