/**
* 建立failure表
*/
private void constructFailureStates()
{
Queue <State> queue = new LinkedBlockingDeque <State>();
// 第一步，将深度为1的节点的failure设为根节点
for (State depthOneState : this.rootState.getStates())
{
depthOneState.setFailure(this.rootState);
queue.add(depthOneState);
}
this.failureStatesConstructed = true;
// 第二步，为深度 > 1 的节点建立failure表，这是一个bfs
while (!queue.isEmpty())
{
State currentState = queue.remove();
for (Character transition : currentState.getTransitions())
{
State targetState = currentState.nextState(transition);
queue.add(targetState);
State traceFailureState = currentState.failure();
while (traceFailureState.nextState(transition) == null)
{
traceFailureState = traceFailureState.failure();
}
State newFailureState = traceFailureState.nextState(transition);
targetState.setFailure(newFailureState);
targetState.addEmit(newFailureState.emit());
}
}
}
