---Copyright:	 Matra Datavision 1992
---Version: 

---History:
--  Version	Date         Purpose
--              10/12/92     Creation   


generic class HDoubleMap from PCollection ( Key as Storable ;
                                          Item as Storable ;
                                          KeyHash as Hash(Key) ;
                                          ItemHash as Hash(Item) )

---Purpose: A double map is a Collection of bindings between two objects.
-- It can be retrieved either by its Key or its Item;a hash code
-- value must be computed for both.

inherits Persistent from Standard

raises

    MultiplyDefined from Standard,
    NoMoreObject    from Standard,
    NoSuchObject    from Standard


class DoubleMapNode from PCollection inherits PManaged from PMMgt
---Purpose: Class used in the implementation of the DoubleMap class. It stores
-- Key and Item and two references to DoubleMapNode, one used to make Hashed 
-- list for Key , the other to make Hashed list for Item.

is

    Create( aKey : Key ; anItem : Item ; nextKey : DoubleMapNode ; 
    	nextItem : DoubleMapNode ) returns mutable DoubleMapNode;
    ---Purpose: Creates a DoubleMapNode.

    SetNextKey ( me : mutable ; aNode : DoubleMapNode ) is static;
    ---Level: Internal
    ---Purpose: Sets the next node of Key hashed list. 

    SetNextItem ( me : mutable ; aNode : DoubleMapNode ) is static;
    ---Level: Internal
    ---Purpose: Sets the next node of Item hashed list. 
    
    GetKey ( me ) returns any Key is static;
    ---Level: Internal
    ---Purpose: Returns the key.

    GetItem ( me ) returns any Item is static;
    ---Level: Internal
    ---Purpose: Returns the item.

    NextKey ( me ) returns any DoubleMapNode is static;
    ---Level: Internal
    ---Purpose: Returns the next node of Key hashed list.

    NextItem ( me ) returns any DoubleMapNode is static;
    ---Level: Internal
    ---Purpose: Returns the next node of Item hashed list.

fields

    myKey      : Key;
    myItem     : Item;
    myNextKey  : DoubleMapNode;
    myNextItem : DoubleMapNode;
    
end DoubleMapNode;

class ArrayDoubleMap instantiates HArray1 from PCollection (DoubleMapNode);


class DoubleMapIterator

---Purpose: This class provides services to iterate on all bindings of
-- a DoubleMap.

raises
    
    NoMoreObject from Standard,
    NoSuchObject from Standard
    
is

    Create ( aDoubleMap : HDoubleMap from PCollection) 
                               returns DoubleMapIterator;
    ---Purpose: Creates an iterator of <aDoubleMap>.

    More ( me ) returns Boolean;
    ---Level: Public
    ---Purpose: Returns True if there are others couples (Item,Key).

    Next ( me : in out )
    ---Level: Public
    ---Purpose: Sets the iterator to the next couple (Item,Key).
    raises NoMoreObject from Standard;

    KeyValue ( me ) returns Key
    ---Level: Public
    ---Purpose: Returns the Key value corresponding to the current position 
    -- of the iterator.
    raises NoSuchObject from Standard;

    ItemValue ( me ) returns Item
    ---Level: Public
    ---Purpose: Returns the Item value corresponding to the current position 
    -- of the iterator.
    raises NoSuchObject from Standard;

fields

    myBuckets      : ArrayDoubleMap;
    myCurrentIndex : Integer;
    myCurrentNode  : DoubleMapNode;
    
end DoubleMapIterator;
    
is

    Create ( NbBuckets : Integer; fhKey : KeyHash; fhItem : ItemHash )
    	returns mutable HDoubleMap;
    ---Purpose: Creates a double map of <NbBuckets> entries.
	
    NbBuckets ( me ) returns Integer;
    ---Level: Public
    ---Purpose: Returns the number of entries in the double map <me>.
    
    Extent ( me ) returns Integer;
    ---Level: Public
    ---Purpose: Returns the number of couples (<Key>,<Item>) stored in <me>.
    
    Bind ( me : mutable ; aKey : Key; anItem : Item )
    ---Level: Public
    ---Purpose: Adds the pair (<aKey>,<anItem>) to <me>.
    ---Trigger: Raises an exception if the binding already exists.
    raises MultiplyDefined from Standard;
    
    FindItem ( me ; aKey : Key ) returns any Item
    ---Level: Public
    ---Purpose: Returns the item bounded by <aKey>.
    ---Trigger: Raises an exception if the binding does not exist.
    raises NoSuchObject from Standard;
    
    FindKey ( me ; anItem : Item ) returns any Key
    ---Level: Public
    ---Purpose: Returns the key bounded by <anItem>.
    raises NoSuchObject from Standard;
    ---Trigger: Raises if the binding does not exist.
    
    UnbindKey ( me : mutable ; aKey : Key )
    ---Level: Public
    ---Purpose: Unbinds the couple keyed by <aKey>.
    raises NoSuchObject from Standard;
    ---Trigger: Raises if the binding does not exist.
    
    UnbindItem ( me : mutable ; anItem : Item )
    ---Level: Public
    ---Purpose: Unbinds the couple keyed by <anItem>.
    raises NoSuchObject from Standard;
    ---Trigger: Raises if the binding does not exist.
    
    Clear ( me : mutable );
    ---Level: Public
    ---Purpose: Clears the double map.
    
    IsBoundByKey ( me ; aKey : Key ) returns Boolean;
    ---Level: Public
    ---Purpose: Returns True if an element is bound by <aKey>.
    
    IsBoundByItem ( me ; anItem : Item ) returns Boolean;
    ---Level: Public
    ---Purpose: Returns True if an element is bound by <anItem>.

    IsEmpty ( me ) returns Boolean;
    ---Level: Public
    ---Purpose: Returns True if the DoubleMap <me> is empty.

    GetArrayKey ( me ) returns ArrayDoubleMap is static private;
    ---Level: Internal
    ---Purpose: Returns the ArrayDoubleMap for Key.

fields

    myNumber    : Integer;  -- Number of couples
    myArrayKey  : ArrayDoubleMap;   
    myArrayItem : ArrayDoubleMap;   
    myKeyHash   : KeyHash;
    myItemHash  : ItemHash;
    
friends

    class DoubleMapIterator from PCollection
    
end HDoubleMap;