Extend the Ex42 observer pattern with Hint objects so each observer receives the reason for the update instead of querying the subject: - Subject::notify() and Observer::update() now take a const Hint& argument. - Add LightHint and WaitHint carrying the traffic light state and WAIT button state, defined in Pelican.h. - Pole dispatches on hint type using dynamic_cast. - The Pole constructor sets its initial lights directly from the Pelican's current state, since no notification is sent at startup. Stopgap until the initial update is handled properly. Co-authored-by: Qwen 3.8 27B <qwen3.8_27b-q3_k_xl@lmstudio.local>
58 lines
1.3 KiB
C++
58 lines
1.3 KiB
C++
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#include "Pelican.h"
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#include "PelicanTimer.h"
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#include "Subject.h"
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Pelican::Pelican() : pressed(false), RED_TIME(4), YELLOW_TIME(2), GREEN_TIME(3), FLASH_TIME(5), state(GREEN_IDLE) {
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myTimer = new PelicanTimer(*this, &Pelican::timerExpired);
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}
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void Pelican::press(void) {
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if (state == GREEN_IDLE) {
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state = YELLOW_STATE;
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myTimer->timeoutRequest(YELLOW_TIME);
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pressed = true;
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} else if (state != RED_STATE) {
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pressed = true;
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}
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notify(LightHint(state));
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notify(WaitHint(pressed));
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}
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void Pelican::timerExpired(void) {
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switch (state) {
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case RED_STATE:
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state = YELLOW_FLASHING;
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myTimer->timeoutRequest(FLASH_TIME);
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break;
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case YELLOW_FLASHING:
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state = GREEN_TIMING;
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myTimer->timeoutRequest(GREEN_TIME);
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break;
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case GREEN_TIMING:
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if (pressed) {
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state = YELLOW_STATE;
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myTimer->timeoutRequest(YELLOW_TIME);
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} else {
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state = GREEN_IDLE;
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}
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break;
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case GREEN_IDLE:
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// should never happen
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break;
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case YELLOW_STATE:
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state = RED_STATE;
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pressed = false;
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myTimer->timeoutRequest(RED_TIME);
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break;
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}
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notify(LightHint(state));
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notify(WaitHint(pressed));
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}
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