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package de.thedevstack.conversationsplus.enums;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
/**
*/
public enum MessageStatus {
WAITING,
TRANSMITTING,
TRANSMITTED,
FAILED,
CANCELED,
DISPLAYED,
RECEIVED;
static {
/*
* Initialization of valid next states in this block,
* because the enum values need to be known at initialization.
* If trying to initialize in Constructor, then only forward transitions are possible.,
* no way to handle jumping back.
*/
WAITING.initValidNextStates(TRANSMITTING);
TRANSMITTING.initValidNextStates(FAILED, TRANSMITTED, CANCELED);
CANCELED.initValidNextStates(WAITING);
FAILED.initValidNextStates(WAITING);
// Restrict some transitions to be only valid for outgoing messages
TRANSMITTED.initValidNextStatesForDirection(MessageDirection.OUT, RECEIVED, DISPLAYED);
RECEIVED.initValidNextStatesForDirection(MessageDirection.OUT, DISPLAYED);
}
private List<MessageStatus> validNextStates;
private HashMap<MessageDirection, List<MessageStatus>> directionRestricted = new HashMap<>();
private void initValidNextStates(MessageStatus... validNextStates) {
this.validNextStates = Arrays.asList(validNextStates);
}
private void initValidNextStatesForDirection(MessageDirection direction, MessageStatus... newStatus) {
this.directionRestricted.put(direction, Arrays.asList(newStatus));
}
public boolean isTransitionToStateAllowed(MessageStatus newStatus, MessageDirection direction) {
boolean hasNoValidNextStates = this.validNextStates.isEmpty() && (!this.directionRestricted.containsKey(direction) || this.directionRestricted.get(direction).isEmpty());
boolean isValidNextState = this.validNextStates.contains(newStatus);
boolean isValidNextStateForDirection = (this.directionRestricted.containsKey(direction) && this.directionRestricted.get(direction).contains(newStatus));
return hasNoValidNextStates // no valid next states -> every new state is allowed
|| isValidNextState // if newStatus is conditionless
|| isValidNextStateForDirection; // if the newStatus is valid for the direction
}
}
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