Fan

 

final class

sys::Map

sys::Obj
  sys::Map

Map is a hash map of key/value pairs.

See docCookbook::Maps for coding examples.

Slots

addSource

M add(K key, V val)

Add the specified key/value pair to the map. If the key is already mapped, then throw the ArgErr. Return this. If key does not return true for Obj.isImmutable, then throw NotImmutableErr. If key is null throw NullErr. Throw ReadonlyErr if readonly.

addAllSource

M addAll(M m)

Append the specified map to this map by adding every key/value in m in this map. If any key in m is already mapped then this method will fail (any previous keys will remain mapped potentially leaving this map in an inconsistent state). Return this. Throw ReadonlyErr if readonly. Also see setAll. This method is semanatically equivalent to:

m.each |K k, V v| { this.add(k, v) }
addListSource

M addList(V[] list, |V, Int -> K|? c := null)

Add the specified list to this map where the values are the list items and the keys are derived by calling the specified function on each item. If the function is null, then the items themselves are used as the keys. If any key already mapped then this method will fail (any previous keys will remain mapped potentially leaving this map in an inconsistent state). Return this. Throw ReadonlyErr if readonly. Also see setList.

Examples:

m := [0:"0"]
m.addList(["1","2"]) |Str s->Int| { return s.toInt }
m  =>  [0:0, 1:1, 2:2]
allSource

Bool all(|V, K -> Bool| c)

Return true if c returns true for all of the key/value pairs in the map. If the list is empty, return true. This method is idempotent.

anySource

Bool any(|V, K -> Bool| c)

Return true if c returns true for any of the key/value pairs in the map. If the map is empty, return false. This method is idempotent.

caseInsensitiveSource

Bool caseInsensitive := false

This field configures case sensitivity for maps with Str keys. When set to true, Str keys are compared without regard to case for the following methods: get, containsKey, set, add, setAll, addAll, and remove methods. Only ASCII character case is taken into account. The original case is preserved (keys aren't made all lower or upper case). This field defaults to false.

Getting this field is idempotent. If you attempt to set this method on a map which is not empty or not typed to use Str keys, then throw UnsupportedOperation. Throw ReadonlyErr if set when readonly. This mode cannot be used concurrently with ordered.

clearSource

M clear()

Remove all key/value pairs from the map. Return this. Throw ReadonlyErr if readonly.

containsKeySource

Bool containsKey(K key)

Return if the specified key is mapped. This method is idempotent.

defSource

V? def

The default value to use for get when a key isn't mapped. This field defaults to null. The value of def must be immutable or NotImmutableErr is thrown. Getting this field is idempotent. Throw ReadonlyErr if set when readonly.

dupSource

M dup()

Create a shallow duplicate copy of this Map. The keys and values themselves are not duplicated. This method is idempotent.

eachSource

Void each(|V, K| c)

Call the specified function for every key/value in the list. This method is idempotent.

eachWhileSource

Obj? eachWhile(|V, K -> Obj?| c)

Iterate every key/value pair in the map until the function returns non-null. If function returns non-null, then break the iteration and return the resulting object. Return null if the function returns null for every key/value pair. This method is idempotent.

equalsSource

override Bool equals(Obj? that)

Overrides sys::Obj.equals

Two Maps are equal if they have the same type and number of equal key/value pairs.

Examples:

a := Int:Str[1:"one", 2:"two"]
b := Int:Str[2:"two", 1:"one"]
c := Int:Str?[2:"two", 1:"one"]
a == b  =>  true
a == c  =>  false
excludeSource

M exclude(|V, K -> Bool| c)

Return a new map containing the key/value pairs for which c returns false. If c returns true for every item, then return an empty list. The inverse of this method is findAll(). This method is idempotent.

Example:

map := ["off":0, "slow":50, "fast":100]
map.exclude |Int v->Bool| { return v == 0 } => ["slow":50, "fast":100]
findSource

V? find(|V, K -> Bool| c)

Return the first value in the map for which c returns true. If c returns false for every pair, then return null. This method is idempotent.

findAllSource

M findAll(|V, K -> Bool| c)

Return a new map containing the key/value pairs for which c returns true. If c returns false for every item, then return an empty map. The inverse of this method is exclude(). This method is idempotent.

getSource

V? get(K key, V? def := this.def)

Get the value for the specified key. If key is not mapped, then return the value of the def parameter. If def is omitted it defaults to the def field. This method is idempotent. Shortcut is a[key].

hashSource

override Int hash()

Overrides sys::Obj.hash

Return platform dependent hashcode based on hash of the keys and values.

isEmptySource

Bool isEmpty()

Return if size() == 0. This method is idempotent.

isROSource

Bool isRO()

Return if this Map is readonly. A readonly Map is guaranteed to be immutable (although its values may be mutable themselves). Any attempt to modify a readonly Map will result in ReadonlyErr. Use rw() to get a read-write Map from a readonly Map. Methods documented as idempotent may be used safely with a readonly Map. This method is idempotent.

isRWSource

Bool isRW()

Return if this Map is read-write. A read-write Map is mutable and may be modified. Use ro() to get a readonly Map from a read-write Map. This method is idempotent.

joinSource

Str join(Str separator, |V, K -> Str|? c := null)

Return a string by concatenating each key/value pair using the specified separator string. If c is non-null then it is used to format each pair into a string, otherwise "$k: $v" is used. This method is idempotent.

Example:

keysSource

K[] keys()

Get a list of all the mapped keys. This method is idempotent.

makeSource

new make(Type type)

Constructor with of type (must be Map type).

mapSource

Map map(|V, K -> Obj?| c)

Create a new map with the same keys, but apply the specified closure to generate new values. The new mapped is typed based on the return type of c. This method is idempotent.

Example:

m := [2:2, 3:3, 4:4]
x := m.map |Int v->Int| { return v*2 }
x => [2:4, 3:6, 4:8]
orderedSource

Bool ordered := false

When set to true, the map maintains the order in which key/value pairs are added to the map. The implementation is based on using a linked list in addition to the normal hashmap. This field defaults to false.

Getting this field is idempotent. If you attempt to set this method on a map which is not empty, then throw UnsupportedOperation. Throw ReadonlyErr if set when readonly. This mode cannot be used concurrently with caseInsensitive.

reduceSource

Obj? reduce(Obj? init, |Obj?, V, K -> Obj?| c)

Reduce is used to iterate through every value in the map to reduce the map into a single value called the reduction. The initial value of the reduction is passed in as the init parameter, then passed back to the closure along with each item. This method is idempotent.

Example:

m := ["2":2, "3":3, "4":4]
m.reduce(100) |Obj r, Int v->Obj| { return (Int)r + v } => 109
removeSource

V? remove(K key)

Remove the key/value pair identified by the specified key from the map and return the value. If the key was not mapped then return null. Throw ReadonlyErr if readonly.

roSource

M ro()

Get a readonly, immutable Map instance with the same contents as this Map (although its values may be mutable themselves). If this Map is already readonly, then return this. Only methods documented as idempotent may be used safely with a readonly Map, all others will throw ReadonlyErr. This method is idempotent.

rwSource

M rw()

Get a read-write, mutable Map instance with the same contents as this Map. If this Map is already read-write, then return this. This method is idempotent.

setSource

M set(K key, V val)

Set the value for the specified key. If the key is already mapped, this overwrites the old value. If key is not yet mapped this adds the key/value pair to the map. Return this. If key does not return true for Obj.isImmutable, then throw NotImmutableErr. If key is null throw NullErr. Throw ReadonlyErr if readonly.

setAllSource

M setAll(M m)

Append the specified map to this map by setting every key/value in m in this map. Keys in m not yet mapped are added and keys already mapped are overwritten. Return this. Throw ReadonlyErr if readonly. Also see addAll. This method is semanatically equivalent to:

m.each |K k, V v| { this.set(k, v) }
setListSource

M setList(V[] list, |V, Int -> K|? c := null)

Add the specified list to this map where the values are the list items and the keys are derived by calling the specified function on each item. If the function is null, then the items themselves are used as the keys. If any key already mapped then it is overwritten. Return this. Throw ReadonlyErr if readonly. Also see addList.

Examples:

m := [0:"0", 2:"old"]
m.setList(["1","2"]) |Str s->Int| { return s.toInt }
m  =>  [0:0, 1:1, 2:2]
sizeSource

Int size()

Get the number of key/value pairs in the list. This method is idempotent.

toCodeSource

Str toCode()

Get this map as a Fan expression suitable for code generation. The individual keys and values must all respond to the toCode method.

toImmutableSource

M toImmutable()

Return an immutable Map which returns true for Obj.isImmtable. If this Map is already immutable, then return this. This method is effectively a "deep ro()" which guarantees that if any values are Lists or Maps, then they are made immutable by recursively calling toImmutable. All other values must return true for Obj.isImmutable, otherwise NotImmutableErr is thrown. This method must be used whenever setting a const Map field. This method is idempotent.

toStrSource

override Str toStr()

Overrides sys::Obj.toStr

Return a string representation the Map. This method is idempotent.

valuesSource

V[] values()

Get a list of all the mapped values. This method is idempotent.