Oolite JavaScript Reference: System

Prototype: Object
Subtypes: none

The System class represents the current system. There is always one System object, available through the global property system.

Attempts to change system properties are ignored in interstellar space (i.e., the place you end up in after a witchspace malfunction).

Properties

allShips

allShips : Array (read-only)

A list of the ships in the system.

See Also: entitiesWithScanClass(), filteredEntities(), shipsWithPrimaryRole(), shipsWithRole()

description

description : String (read/write)

The description of the current system, as seen on the planet info screen.

economy

economy : Number (integer, read/write)

The type of economy in the current system, ranging from 0 (Rich Industrial) to 7 (Poor Agricultural).

See Also: economyDescription

economyDescription

economyDescription : String (read-only)

A description of the economy type, for example, “Mostly Industrial”.

See Also: economy

government

government : Number (read/write, integer)

The type of government in the current system, ranging from 0 (Anarchy) to 7 (Corporate State).

See Also: governmentDescription

governmentDescription

governmentDescription : String (read-only)

A description of the government type, for example, “Democracy”.

See Also: government

ID

ID : Number (integer, read-only)

A number identifying the system. 0 to 255, or -1 for interstellar space.

info

info : SystemInfo (read/write)

Allows access to system properties, using the same keys as planetinfo.plist.

Example:

System.info.description = "This is a dull planet.";

inhabitantsDescription

inhabitantsDescription : String (read/write)

The description of the inhabitants of the current system, such as “Slimy Blue Frogs”.

isInterstellarSpace

isInterstellarSpace : Boolean (read-only)

true if the current system is in interstellar space, false otherwise.

mainPlanet

mainPlanet : Planet (read-only)

The system’s main planet, or null if there is none.

mainStation

mainStation : Station (read-only)

The system’s main station, or null if there is none.

name

This property was first documented in connection with Oolite 1.74, although it existed earlier.

name : String (read/write)

The name of the system.

planets

planets : Array (read-only)

A list of the planets in the system.

population

population : Number (integer, read/write)

The population of the current system.

productivity

productivity : Number (integer, read/write)

The productivity of the current system.

pseudoRandom100

pseudoRandom100 : Number (integer, read-only)

A random number between 0 and 99 that is always the same for a given system. Important: this method has the undesirable side effect of resetting the system random number generator. It should only be used for backwards-compatibility. For new development, use pseudoRandomNumber.

pseudoRandom256

pseudoRandom256 : Number (integer, read-only)

A random number between 0 and 255 that is always the same for a given system. Important: this method has the undesirable side effect of resetting the system random number generator. It should only be used for backwards-compatibility. For new development, use pseudoRandomNumber.

pseudoRandomNumber

pseudoRandomNumber : Number (read-only)

A random number between 0 and 1 that is always the same for a given system.

Note: It’s important to keep in mind that this property is the same for every OXP, so if two OXPs use it in the same way they will tend to cause things to happen at the same time. for instance, if several OXPs add stations to 25 % of systems using if (system.pseudoRandomNumber <= 0.25), their stations will all appear in the same system. The recommended solution is to use a scrambling function, as demonstrated in this forum post. That function is mathematically sound and tested; it is suggested that you use it without modification (picking your own “salt” value).

sun

sun : Sun (read-only)

The system’s sun, or null if there is none.

techLevel

techLevel : Number (integer, read/write)

The technology level of the current system, ranging from 0 to 15.

Methods

addGroup

This method was added in Oolite test release 1.74.

function addGroup(role : String, count : Number [, position: vectorExpression] [, radius: Number]) : ShipGroup

Like addShips(), but puts the ships in a group and returns the group.

See Also: addGroupToRoute(), addShips()

addGroupToRoute

This method was added in Oolite test release 1.74.

function addGroupToRoute(role : String, count : Number [, fraction: Number] [, route: String]) : ShipGroup

Like addShipsToRoute(), but puts the ships in a group and returns the group.

See Also: addGroup(), addShipsToRoute()

addMoon

function addMoon(planetInfoKey : String) : Planet

Adds a moon to the system, using the specified entry in planetinfo.plist. A moon is the same as a planet, except that it has no atmosphere.

See Also: addPlanet()

addPlanet

function addPlanet(planetInfoKey : String) : Planet

Adds a planet to the system, using the specified entry in planetinfo.plist.

See Also: addMoon()

addShips

This method was added in Oolite test release 1.74.

function addShips(role : String, count : Number [, position: vectorExpression] [, radius: Number]) : Array

Adds ships to the system and returns the added ships in an array. Position is in absolute coordinates. When no position is given, the witchpoint is assumed. When no radius is given, the maximum scanner range is used. Ships added in range of the witchpoint automatically create a witchpoint entry cloud.

See Also: addGroup(), addShipsToRoute()

addShipsToRoute

This method was added in Oolite test release 1.74.

function addShipsToRoute(role : String, count : Number [, fraction: Number] [, route: String]) : Array

Adds ships to the system on certain common routes and returns the added ships as an array. The routes are the two character codes wp, pw, ws, sw, sp, and ps, where w stands for the witchpoint, p for the planet and s for the sun.

When no route is defined, the route witchpoint → main station is assumed.

The position is a fraction of the route and must be between 0 and 1. Unlike the legacy commands the fraction takes planetary radii in account, so it does not start counting in the centre of sun/planet but from its surface. When no fraction is defined, a random fraction is chosen. Ships are added within scanner range of this position. Ships added in range of the witchpoint automatically create a witchpoint entry cloud.

Example:

var ships = system.addShipsToRoute("myShips", 2, 0.7, "sw")

adds 2 ships near each-other on the route from sun to witchpoint and puts the added ship in the array ships.

See Also: addGroup(), addShips()

countShipsWithPrimaryRole

function countShipsWithPrimaryRole(role : String) : Number (integer)

Returns the number of ships with the specified primary role in the system.

countShipsWithRole

function countShipsWithRole(role : String) : Number (integer)

Returns the number of ships with the specified role in the system. Counts not only the primary role the ship is added with but all roles a ship can have.

entitiesWithScanClass

function entitiesWithScanClass(scanClass : String [, relativeTo : Entity [, range : Number]]) : Array

A list of the entities in the system whose scan class is scanClass. If relativeTo is specified, the list will be sorted in order of proximity to relativeTo (i.e., the first element of the list is closest). If range is also specified, entities further than range metres from relativeTo will be excluded. If no matching entities are found, an empty array is returned.

See Also: shipsWithPrimaryRole(), shipsWithRole(), filteredEntities().

filteredEntities

function filteredEntities(this : Object, predicate : Function [, relativeTo : Entity [, range : Number]]) : Array

A list of the entities for which predicate returns true. If relativeTo is specified, the list will be sorted in order of proximity to relativeTo (i.e., the first element of the list is closest). If range is also specified, entities further than range metres from relativeTo will be excluded. If no matching entities are found, an empty array is returned.

Example:

this.findIdlePoliceInScannerRange = function()
{
    function isIdlePolice(entity)
    {
        return entity.isShip && entity.isPolice && !entity.target
    }
  
    return system.filteredEntities(this, isIdlePolice, player, 25600);
}

See Also: shipsWithPrimaryRole(), shipsWithRole(), entitiesWithScanClass().

legacy_addShips etc.

function legacy_addShips(role : String, count : Number)
function legacy_addSystemShips(role : String, count : Number, position : Number)
function legacy_addShipsAt(role : String, count : Number, coordscheme : String, where : vectorExpression)
function legacy_addShipsAtPrecisely(role : String, count : Number, coordscheme : String, where : Planet)
function legacy_addShipsWithinRadius(role : String, count : Number, coordScheme : String, where : Planet, radius : Number)
function legacy_spawnShip(shipDataKey : String)

Various ways of causing ships to appear. Each of these corresponds to a legacy scripting method. For more info about the coordScheme, look at Oolite coordinate systems. These methods are kept for backwards-compatibility; for new development, addShips() is preferred.

Important: legacy_spawn, previously listed here, never worked as intended and has been replaced with Ship.spawn().

sendAllShipsAway

function sendAllShipsAway()

Makes all ships hyperspace out of the system.

shipsWithPrimaryRole

function shipsWithPrimaryRole(role : String [, relativeTo : Entity [, range : Number]]) : Array

A list of the entities in the system whose primary role is role. If relativeTo is specified, the list will be sorted in order of proximity to relativeTo (i.e., the first element of the list is closest). If range is also specified, entities further than range metres from relativeTo will be excluded. If no matching entities are found, an empty array is returned.

See Also: shipsWithRole(), entitiesWithScanClass(), filteredEntities().

shipsWithRole

function shipsWithRole(role : String [, relativeTo : Entity [, range : Number]]) : Array

A list of the entities in the system whose role set contains role. If relativeTo is specified, the list will be sorted in order of proximity to relativeTo (i.e., the first element of the list is closest). If range is also specified, entities further than range metres from relativeTo will be excluded. If no matching entities are found, an empty array is returned.

See Also: shipsWithRole(), entitiesWithScanClass(), filteredEntities().

Static Methods

infoForSystem

function infoForSystem(galaxyNumber: Integer, systemID : Integer) (write-only)

Overwrites existing info of the given system. As properties it uses the planetinfo.plist keys. e.g.

System.infoForSystem(0, 55).description = "This is a dull planet."

sets the description of planet nr 55 in galaxy 0 to his is a dull planet."

Starting from Oolite 1.73, all system Info for the present galaxy is also readable. Even though any galaxy system info property is fully settable, due to engine limitations other galaxies' data is not accessible. In other words

System.infoForSystem(0, 55).description

would return "This is a dull planet." if called from galaxy 0, null from the other galaxies.

systemIDForName

function systemIDForName(systemName : String) : Integer

Returns the ID number of a system in the current galaxy based on the system name)

systemNameForID

function systemNameForID(systemID : Integer) : String

Returns the name of a system in the current galaxy based on the given ID number)