Today I automated the generation of entity IDs.<\/p>\n
First we create a basic counter.<\/p>\n
\r\n var globalIDCounter = 0;\r\n function getNewID() {\r\n return ++globalIDCounter;\r\n }\r\n<\/pre>\nThen we change the entity declarations to remove the explicit assignment of IDs as we have been doing.<\/p>\n
\r\n function entity1(initialTime,incrementTime,endTime) {\r\n this.entityID = getNewID();\r\n<\/pre>\nThat was pretty mindless, so let’s also add a new type of entity, following the form of the original one. Here’s the original. It just advances its own clock and reinserts itself back into the future events queue.<\/p>\n
\r\n function entity1(initialTime,incrementTime,endTime) {\r\n this.entityID = getNewID();\r\n this.initialTime = initialTime;\r\n this.incrementTime = incrementTime;\r\n this.endTime = endTime;\r\n this.nextState = \"increment\";\r\n feq.newItem(initialTime,this);\r\n displayProgressText(\"entity \"+this.entityID+\" created at time \"+globalSimClock+\"
\");\r\n\r\n this.activate = function() {\r\n if (this.nextState == \"increment\") {\r\n displayProgressText(\"entity \"+this.entityID+\" updated at time \"+globalSimClock+\"
\");\r\n if (globalSimClock + this.incrementTime >= this.endTime) {\r\n this.nextState = \"destroy\";\r\n }\r\n advance(this.incrementTime);\r\n } else if (this.nextState == \"destroy\") {\r\n displayProgressText(\"entity \"+this.entityID+\" terminated at time \"+globalSimClock+\"
\");\r\n } else {\r\n alert(\"entity \"+this.entityID+\" went into undefined state\");\r\n displayProgressText(\"entity \"+this.entityID+\" in undefined state at time \"+globalSimClock+\"
\");\r\n }\r\n }; \/\/this.activate \r\n }; \/\/entity\r\n<\/pre>\nHere’s the new one. It also updates its clock and inserts itself back into the future events queue, but in this case it implements a more interesting (though still mindlessly simple) behavior. It increments a location property which itself gets incremented, until it reaches a final offset, whereupon it counts down through a five-step wait process. Then it stops reinserting itself back into the future events queue.<\/p>\n
In reality we would always create entities that carry out more interesting behaviors.<\/p>\n
\r\n function entity2(initialTime,initialPosition,speed,endPosition) {\r\n this.entityID = getNewID();\r\n this.initialTime = initialTime;\r\n this.currentPosition = initialPosition;\r\n this.speed = speed;\r\n this.endPosition = endPosition;\r\n this.nextState = \"go_forward\";\r\n this.waitCountdown = 5;\r\n feq.newItem(initialTime,this);\r\n displayProgressText(\"entity \"+this.entityID+\" created at time \"+globalSimClock+\"
\");\r\n this.activate = function() {\r\n if (this.nextState == \"go_forward\") {\r\n displayProgressText(\"entity \"+this.entityID+\" updated at time \"+globalSimClock+\" position: \"+this.currentPosition+\"
\");\r\n this.currentPosition += this.speed;\r\n if (this.currentPosition >= this.endPosition) {\r\n if (this.currentPosition > this.endPosition) {\r\n this.currentPosition = this.endPosition;\r\n }\r\n this.nextState = \"wait\";\r\n }\r\n advance(7.01);\r\n } else if (this.nextState == \"wait\") {\r\n this.waitCountdown--;\r\n displayProgressText(\"entity \"+this.entityID+\" waiting at time \"+globalSimClock+\" wait count: \"+this.waitCountdown+\"
\");\r\n if (this.waitCountdown <= 0.0) {\r\n this.nextState = \"destroy\";\r\n }\r\n advance(7.01);\r\n } else if (this.nextState == \"destroy\") {\r\n displayProgressText(\"entity \"+this.entityID+\" terminated at time \"+globalSimClock+\"
\");\r\n } else {\r\n alert(\"entity \"+this.entityID+\" went into undefined state\");\r\n displayProgressText(\"entity \"+this.entityID+\" in undefined state at time \"+globalSimClock+\"
\");\r\n }\r\n }; \/\/this.activate \r\n }; \/\/entity\r\n<\/pre>\nHaving to rely on passive garbage collection to officially deallocate or “destroy” objects in JavaScript is kind of annoying but it is what it is. Doing demos in this language makes it easy to post working demos.<\/p>\n
Here’s how the entities are initialized.<\/p>\n
\r\n var entityA = new entity1(11.0,10.0,100.0);\r\n var entityB = new entity1(13.0,13.0,100.0);\r\n var entityC = new entity2(12.0,-40,5,-1);\r\n<\/pre>\nHere is the output generated:
\n
\n104 minutes<\/p>\nentity 1 created at time 0
\nentity 2 created at time 0
\nentity 3 created at time 0
\nentity 1 updated at time 11
\nentity 3 updated at time 12 position: -40
\nentity 2 updated at time 13
\nentity 3 updated at time 19.009999999999998 position: -35
\nentity 1 updated at time 21
\nentity 2 updated at time 26
\nentity 3 updated at time 26.019999999999996 position: -30
\nentity 1 updated at time 31
\nentity 3 updated at time 33.029999999999994 position: -25
\nentity 2 updated at time 39
\nentity 3 updated at time 40.03999999999999 position: -20
\nentity 1 updated at time 41
\nentity 3 updated at time 47.04999999999999 position: -15
\nentity 1 updated at time 51
\nentity 2 updated at time 52
\nentity 3 updated at time 54.05999999999999 position: -10
\nentity 1 updated at time 61
\nentity 3 updated at time 61.069999999999986 position: -5
\nentity 2 updated at time 65
\nentity 3 waiting at time 68.07999999999998 wait count: 4
\nentity 1 updated at time 71
\nentity 3 waiting at time 75.08999999999999 wait count: 3
\nentity 2 updated at time 78
\nentity 1 updated at time 81
\nentity 3 waiting at time 82.1 wait count: 2
\nentity 3 waiting at time 89.11 wait count: 1
\nentity 2 updated at time 91
\nentity 1 updated at time 91
\nentity 3 waiting at time 96.12 wait count: 0
\nentity 1 terminated at time 101
\nentity 3 terminated at time 103.13000000000001
\nentity 2 terminated at time 104<\/code><\/p>\n","protected":false},"excerpt":{"rendered":"
Today I automated the generation of entity IDs. First we create a basic counter. var globalIDCounter = 0; function getNewID() { return ++globalIDCounter; } Then we change the entity declarations to remove the explicit assignment of IDs as we have … Continue reading