=Datatype=
In Databoard all values have a type representation, [../javadoc/org/simantics/databoard/type/Datatype.html|Datatype]. 
It is the base abstract class for all concrete type classes (See table below). 
There is a facade class utility ([../javadoc/org/simantics/databoard/Datatypes.html|Datatypes]) that provides functions to most of the Datatype library's features.

'''[../javadoc/org/simantics/databoard/type|org.simantics.databoard.type]'''.
{| style="background-color: #f9f9f9; border: 1px solid #aaaaaa; "
|- style="background-color: #e9e9e9; " |
| '''Class''' || '''Description'''
|- 
| [../javadoc/org/simantics/databoard/type/Datatype.html|Datatype] || Base class for all data types
|- 
| [../javadoc/org/simantics/databoard/type/RecordType.html|RecordType] || Record 
|- 
| [../javadoc/org/simantics/databoard/type/ArrayType.html|ArrayType] || Array - an ordered sequence of elements of one type.
|- 
| [../javadoc/org/simantics/databoard/type/MapType.html|MapType] || Map - an ordered map of keys to values. 
|- 
| [../javadoc/org/simantics/databoard/type/UnionType.html|UnionType] || Union
|- 
| [../javadoc/org/simantics/databoard/type/BooleanType.html|BooleanType],[../javadoc/org/simantics/databoard/type/IntType.html|IntType],[../javadoc/org/simantics/databoard/type/LongType.html|LongType],[../javadoc/org/simantics/databoard/type/FloatType.html|FloatType],[../javadoc/org/simantics/databoard/type/DoubleType.html|DoubleType]
| Primitive and numeric types
|- 
| [../javadoc/org/simantics/databoard/type/StringType.html|StringType] || String 
|- 
| [../javadoc/org/simantics/databoard/type/OptionalType.html|OptionalType] || Optional value
|- 
| [../javadoc/org/simantics/databoard/type/VariantType.html|VariantType] || Variant value
|}


Datatype can be acquired or created using one of the following methods:
* Construct new
* Constant 
* [[binding#Reflection|Reflection]]-Read from a Class
* Read from string of [[Databoard_Specification|the text notation]].
<pre class="code">
    Datatype type = new DoubleType();
    Datatype type = Datatypes.DOUBLE;
    Datatype type = Datatypes.getDatatype( Double.class );
    
    Datatypes.addDefinition("type Node = { id : String; children : Node[] }");
    Datatype type = Datatypes.getDatatype("Node");
</pre>

==Parsing==
Datatypes are parsed using <code>Datatypes.DatatypeRepository</code>. 
<pre class="code">
    Datatypes.addDefinition("type Node = { id : String; children : Node[] }");
    Datatype type = Datatypes.getDatatype("Node");
</pre>

Types are printed to types and definitions with 
<pre class="code">
    String type = type.toString();
    
    DatatypeRepository repo = new DatatypeRepository();
    repo.add("temp1", type);
    String typeDef = repo.toString();
</pre>

==Structure Example==
A node is a recursive type. With databoard typesystem it could be stated as
<pre class="code">
  type Node = {
         id : String;
         displayNames : LocalizedTexts;
         children : Node[];
         value : Optional(Variant);
       }
</pre>

[[Image:NodeType.png|Type presented as tree]]


A couple of instances with Databoard value notation:
<pre class="code">
  root : Node = {
           id = “PI_01”
           displayNames = map{ “en” = “Instrument “ }
           children = 
            [ 
              {id=”Child”, 
               displayNames = map{ “en” = “Child”} },
               value = 5 : Integer
              }
            ]
           value = “<root>” : String
         }
</pre>

[[Image:NodeInstance.png|Node values preseted as tree]]