Flag - boolean variable that stays true after being set true (thread-safe) [1000915]

sclass Flag is Runnable {
  private volatile boolean up;

  /** returns true if flag was down before (i.e. flag was actually raised right now) */
  public bool raise() {
    if (up) false;
    synchronized {
      if (up) false;
      up = true;
      notifyAll();
      true;
    }
  }

  run { raise(); }
  
  public void waitUntilUp() ctex {
    if (up) ret;
    synchronized {
      while (!up) wait();
    }
  }

  public bool waitUntilUp(double timeout) {
    if (timeout == infinity()) {
      waitUntilUp();
      ret isUp();
    } else
      ret waitUntilUp(toMS(timeout));
  }
  
  public bool waitUntilUp(long timeout) ctex {
    if (up) ret true;
    synchronized {
      if (!up)
        wait(timeout);
    }
    ret isUp();
  }

  public bool isUp aka get() { ret up; }

  toString { ret isUp() ? "up" : "down"; }
}

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Snippet ID:	#1000915
Snippet name:	Flag - boolean variable that stays true after being set true (thread-safe)
Eternal ID of this version:	#1000915/16
Text MD5:	787466a4713d99bbdfad30f05787c445
Author:	stefan
Category:
Type:	JavaX fragment (include)
Public (visible to everyone):	Yes
Archived (hidden from active list):	No
Created/modified:	2022-06-20 21:37:04
Source code size:	872 bytes / 44 lines
Pitched / IR pitched:	No / No
Views / Downloads:	891 / 9342
Version history:	15 change(s)
Referenced in:	[show references]

< > BotCompany Repo | #1000915 // Flag - boolean variable that stays true after being set true (thread-safe)

JavaX fragment (include) [tags: use-pretranspiled]

Author comment

1	sclass Flag is Runnable {
2	private volatile boolean up;
3
4	/** returns true if flag was down before (i.e. flag was actually raised right now) */
5	public bool raise() {
6	if (up) false;
7	synchronized {
8	if (up) false;
9	up = true;
10	notifyAll();
11	true;
12	}
13	}
14
15	run { raise(); }
16
17	public void waitUntilUp() ctex {
18	if (up) ret;
19	synchronized {
20	while (!up) wait();
21	}
22	}
23
24	public bool waitUntilUp(double timeout) {
25	if (timeout == infinity()) {
26	waitUntilUp();
27	ret isUp();
28	} else
29	ret waitUntilUp(toMS(timeout));
30	}
31
32	public bool waitUntilUp(long timeout) ctex {
33	if (up) ret true;
34	synchronized {
35	if (!up)
36	wait(timeout);
37	}
38	ret isUp();
39	}
40
41	public bool isUp aka get() { ret up; }
42
43	toString { ret isUp() ? "up" : "down"; }
44	}