>) e.createRandom(5);
'''Classes are RecordTypes'''
class Foo {
public int x, y, z;
}
Is a binding to the following Datatype
type Foo = { x : Integer, y : Integer, z : Integer }
'''There are three types of classes supported, and therefore three ways how objects are constructed.'''
If you create binding for your class with Bindings#getBinding( clazz ), the class must adhere one of these format. You may have to add annotations such as @Recursive, @Optional, @Arguments.
''Record-like classes:''
class Foo {
public String name;
public Object value;
}
''Immutable classes:''
class Foo {
private String name;
private Object value;
public Foo(String name, Object value) {
this.name = name;
this.value = value;
}
public String getName() {
return name;
}
public Object getValue() {
return value;
}
}
''Bean-like classes:''
class Foo {
private String name;
private Object value;
public void setName(String name) {
this.name = name;
}
public void setValue(Object value) {
this.value = value;
}
public String getName() {
return name;
}
public Object getValue() {
return value;
}
}
'''Static and transient fields are omited:'''
static final long serialVersionUID = -3387516993124229943L;
transient int hashCode;
'''Enumerations are Union Types'''
enum Cars { Ferrari, Porche, Lamborghini, Jaguar }
is interpreted as union type
type Cars = | Ferrari | Porche | Lamborghini | Jaguar
If you cannot modify the class, you have to create binding for it by subclassing base binding classes, eg. RecordBinding.
'''Other exceptions:'''
*java.lang.Object is Variant.
*java.lang.Set is Map(T, {}).
*java.lang.TreeSet is Map(T, {}).
*java.lang.HashSet is Map(T, {}). (Note HashSet binding has very low performance.)
*java.lang.Map is Map(K, V).
*java.lang.TreeMap is Map(K, V).
*java.lang.HashMap is Map(K, V). (Note HashMap binding has very low performance.)
*java.lang.List is Array(T).
*java.lang.ArrayList is Array(T).
*java.lang.LinkedList is Array(T).
*void is {}.
*The stacktrace of Exception.class is omited.
===Annotations===
Java Classes / Fields can be annotated with the following annotations ('''[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/annotations/|org.simantics.databoard.annotations]]''').
'''UnionTypes are abstract classes or interfaces with @Union annotation.'''
@Union({A.class, B.class}) interface Union1 {
}
class A implements Union1 {
public int value;
}
class B implements Union1 {
public String name;
}
'''@Referable denotes that the class has recursion and is a referable record.'''
public @Referable class Node {
public Node[] children;
}
'''Fields that can have null value have @Optional annotation.'''
@Optional String name;
'''String valid values are set with @Pattern as regular expression. ([http://en.wikipedia.org/wiki/Regular_expression])'''
String @Pattern("(19|20)\\d\\d[- /.](0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])") date;
type Date = String( Pattern = "(19|20)\d\d[- /.](0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])" )
'''String content type is set with a @MIMEType. ([http://en.wikipedia.org/wiki/Mime_type MIME Type])'''
@MIMEType("text/xml") String document;
'''Array size restricted with @Length.'''
@Length("[0..10]") int[] array;
@Length({"[320]", "[240]"}) int[][] image;
'''Valid numeric range is set with @Range.'''
@Range("[0..100]") double alpha;
@Range("[0..]" double length;
'''Range and Length notation:'''
*Exact Value "0"
*Exclude all "()"
*Unlimited "[..]"
*Inclusive range "[0..100]"
*Exclusive range "(0..100)"
*Inclusive lower bound and exclusive upper bound "[0..100)"
'''Engineering unit type is given with @Unit.'''
@Unit("km/h") double maxVelocity;
'''The serializer generated with reflection can be overriden with @SpecializedSerializer'''
@SpecializedSerializer(MySerializer.class)
public class MyRecord {
...
}
== Mapping Scheme ==
A ''binding scheme'' associates some data types with a unique binding. The mapping of types to bindings is bijective, there is one binding for each type and vice-versa.
DefaultBindingScheme is a scheme that converts any datatype to a binding. It prefers java.lang.X primitives.
The Class mapping for each type is listed below.
{| style="background-color: #e9e9e9; border: 1px solid #aaaaaa; "
| '''Type'''
| '''Class'''
|- style="background-color: #f9f9f9; " |
| BooleanType
| Boolean.class
|- style="background-color: #f9f9f9; " |
| ByteType
| Byte.class
|- style="background-color: #f9f9f9; " |
| FloatType
| Float.class
|- style="background-color: #f9f9f9; " |
| DoubleType
| eDouble.class
|- style="background-color: #f9f9f9; " |
| IntegerType
| Integer.class
|- style="background-color: #f9f9f9; " |
| LongType
| Long.class
|- style="background-color: #f9f9f9; " |
| StringType
| String.class
|- style="background-color: #f9f9f9; " |
| UnionType
| TaggedObject.class
|- style="background-color: #f9f9f9; " |
| OptionType
| ValueContainer.class
|- style="background-color: #f9f9f9; " |
| RecordType
| Object[].class
|- style="background-color: #f9f9f9; " |
| ArrayType
| ArrayList.class
|- style="background-color: #f9f9f9; " |
| Array(Byte)
| byte[].class
|- style="background-color: #f9f9f9; " |
| MapType
| TreeMap.class
|- style="background-color: #f9f9f9; " |
| VariantType
| Variant.class
|}
MutableBindingScheme is a scheme that provides a fully implementing mutable binding for all data types.
The Class mapping for each type is listed below.
{| style="background-color: #e9e9e9; border: 1px solid #aaaaaa; "
| '''Type'''
| '''Class'''
|- style="background-color: #f9f9f9; " |
| BooleanType
| MutableBoolean.class
|- style="background-color: #f9f9f9; " |
| ByteType
| MutableByte.class
|- style="background-color: #f9f9f9; " |
| FloatType
| MutableFloat.class
|- style="background-color: #f9f9f9; " |
| DoubleType
| MutableDouble.class
|- style="background-color: #f9f9f9; " |
| IntegerType
| MutableInt.class
|- style="background-color: #f9f9f9; " |
| LongType
| MutableLong.class
|- style="background-color: #f9f9f9; " |
| StringType
| MutableString.class
|- style="background-color: #f9f9f9; " |
| UnionType
| TaggedObject.class
|- style="background-color: #f9f9f9; " |
| OptionType
| ValueContainer.class
|- style="background-color: #f9f9f9; " |
| RecordType
| Object[].class
|- style="background-color: #f9f9f9; " |
| ArrayType
| ArrayList.class
|- style="background-color: #f9f9f9; " |
| MapType
| TreeMap.class
|- style="background-color: #f9f9f9; " |
| VariantType
| Variant.class
|}
===Serialization===
[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/serialization/binary/Serializer.java|Serializer.java]] is a class that serializes Values into and from binary serialization format. It follows the Databoard [[Databoard_Specification#Binary_File_Format|Binary File Format]].
Binding binding = Bindings.DOUBLE;
Serializer serializer = Bindings.getSerializer( binding );
byte[] data = serializer.serialize( new Double( 100.0 ) );
Double value = (Double) serializer.deserialize( data );
Files can be partially accessed using BinaryAccessor, see [[#Accessors|Accessors]]. This is useful when handling larger than memory files.
===Validation===
'''Value''' can be ''well-formed'' or ''valid''.
The domain of valid values are defined with restrictions in data types, and @Length, @Range, @Pattern and @MIMEType Annotations in Classes
Validation mechanism in Binding asserts that the instance is a valid value of the respective Data Type.
try {
Binding.assertInstaceIsValid( object );
} catch( BindingException e ) {
// In-valid object
}
===Other Notes===
*Binding is a Comparator, all data values are comparable, the order is defined in [[Databoard_Specification#Comparison|Specification]].
*Binding#createDefault() creates a valid instance of the Datatype.
*Binding#createRandom(int) creates a valid instance with random values. Useful for unit tests.
*Binding#clone(Object) creates a new instance with same content.
*Binding#readFrom(Object, Binding, Binding) copies contents from another object of same type.
===Parsing & Printing===
Data values are printed and parsed of the [[Databoard_Specification|Text notation]] with the following Binding methods:
String text = binding.printValue( value, true );
Object value = binding.parseValue( text );
And also to value definitions ''name : type = value''
StringBuilder sb = new StringBuilder();
DataValueRepository repo = new DataValueRepository();
repo.put( "temp", binding, value );
binding.printValue( value, sb, repo, true );
String text = sb.toString();
Object value = binding.parseValueDefinition( text );
=Adapter=
There can be different Java Class Bindings for a single data type. For example, Double type can be have bindings DoubleJavaBinding and MutableDoubleBinding to two respective classes java.lang.Double and MutableDouble. Instance of one binding can be adapted to instance of another with an [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/adapter/Adapter.java|Adapter]].
Adapter can be created automatically or implemented self.
Adapter adapter = new Adapter() { ... };
Adapter adapter = Bindings.getAdapter( domainBinding, rangeBinding );
Example:
Adapter adapter = Bindings.getAdapter(Bindings.MUTABLE_DOUBLE, Bindings.DOUBLE);
java.lang.Double double = adapter.adapt( new MutableDouble(5.0) );
There is also convenience.
java.lang.Double double = Bindings.adapt( new MutableDouble(5.0), Bindings.MUTABLE_DOUBLE, Bindings.DOUBLE );
The argument given to Adapter#adapt(Object) may be re-used in the result unless the adapter is a cloning adapter which guarantees a clone. Note, even wih cloning adapters immutable classes, (eg java.lang.Integer) are never cloned.
Adapter cloner = Bindings.adapterCache.getAdapter(domain, range, false, true);
cloner.adapt( ... );
Rectangle2D rect2 = Bindings.clone( rect1, rectBinding, rectBinding );
===Type Conversion===
In some cases different types may be are type-conversion compatible. An instance of one type is convertible to instance of another.
'''Engineering Units of same quantity are convertible.'''
class CarSI {
String modelName;
@Unit("km/h") double maxVelocity;
@Unit("kg") double mass;
@Unit("cm") double length;
@Unit("kW") double power;
}
class CarIm {
String modelName;
@Unit("mph") float maxVelocity;
@Unit("lbs") float mass;
@Unit("ft") float length;
@Unit("hp(M)") float power;
}
Adapter si2imAdapter = Bindings.getTypeAdapter(
Bindings.getBinding(CarSI.class),
Bindings.getBinding(CarIm.class) );
CarIm americanCarInfo = si2imAdapter.adapt( europeanCarInfo );
'''Primitive Types.''' Note, primitive adapter throws an exception at runtime if values are not adaptable.
Adapter adapter = getTypeAdapter( integerBinding, doubleBinding );
Double double = adapter.adapt( new Integer( 5 ) );
'''Records are matched by field names.'''
class Foo {
int x, y, z;
}
class Bar {
int z, y, x;
}
Adapter adapter = getTypeAdapter( fooBinding, barBinding );
'''Subtype to supertype:''' Note, this conversion cannot be not symmetric, supertypes cannot be converted to subtypes.
class Node {
String id;
}
class ValueNode extends Node {
Object value;
}
Adapter adapter = getTypeAdapter( valueNodeBinding, nodeBinding );
'''Non-existing fields to Optional fields'''
class Node {
String id;
}
class NominalNode {
String id;
@Optional String name;
}
Adapter adapter = getTypeAdapter( nodeBinding, nominalNodeBinding );
'''Enumerations'''
enum Cars { Audio, BMW, Mercedes, Honda, Mazda, Toyota, Ford, Mitsubishi, Nissan, GM }
enum JapaneseCars { Honda, Mazda, Toyota, Nissan, Mitsubishi }
Binding carsBinding = Bindings.getBinding( Cars.class );
Binding japaneseCarsBinding = Bindings.getBinding( JapaneseCars.class );
Adapter adapter = Bindings.adapterCache.getAdapter(japaneseCarsBinding, carsBinding, true, false);
=Accessors=
Say, you have several gigabytes of data in a file. The whole object doesn't need to be serialized at once. You can read and write the value partially using [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/|Accessor]] interface. The actual container can be a file, memory byte[]/ByteBuffer or a Java Object. The content is structured as tree using Databoard's type system. All but referable records are supported (=no recursion in accessors).
'''[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor|org.simantics.databoard.accessor]] interfaces'''.
{| style="background-color: #e9e9e9; border: 1px solid #aaaaaa; "
| '''Class'''
| '''Description'''
|- style="background-color: #f9f9f9; " |
| [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/Accessor.java|Accessor]]
| Base class for all data Accessors
|- style="background-color: #f9f9f9; " |
| [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/RecordAccessor.java|RecordAccessor]]
| Record
|- style="background-color: #f9f9f9; " |
| [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/ArrayAccessor.java|ArrayAccessor]]
| Array - an ordered sequence of elements of one value.
|- style="background-color: #f9f9f9; " |
| [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/MapAccessor.java|MapAccessor]]
| Map - an ''ordered'' map of keys to values.
|- style="background-color: #f9f9f9; " |
| [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/UnionAccessor.java|UnionAccessor]]
| Union
|- style="background-color: #f9f9f9; " |
| [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/BooleanAccessor.java|BooleanAccessor]],[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/IntAccessor.java|IntAccessor]],[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/LongAccessor.java|LongAccessor]],[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/FloatAccessor.java|FloatAccessor]],[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/DoubleAccessor.java|DoubleAccessor]]
| Primitive and numeric Accessors
|- style="background-color: #f9f9f9; " |
| [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/StringAccessor.java|StringAccessor]]
| String
|- style="background-color: #f9f9f9; " |
| [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/OptionalAccessor.java|OptionalAccessor]]
| Optional value
|- style="background-color: #f9f9f9; " |
| [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/VariantAccessor.java|VariantAccessor]]
| Variant value
|}
[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/Accessors.java|Accessors]] and [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/Files.java|Files]] are facade classes that contains utilities for instantiating and handling Accessors.
[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/binary/|Binary Accessor]] is an access to a value in binary format (byte[] or ByteBuffer).
'''Example:''' Binary accessor
Datatype type = Datatypes.getDatatype( Rectangle2D.Double.class );
Binding binding = Bindings.getBinding( Rectangle2D.Double.class );
Serializer s = Binding.getSerializer( binding );
// Serialize rectangle
Rectangle2D rect = new Rectangle2D.Double(0,0, 10, 10);
byte[] data = s.serialize(rect);
// Open accessor to byte data and modify first field in the byte data
RecordAccessor ra = Accessors.getAccessor(data, type);
ra.setFieldValue(0, Bindings.DOUBLE, 5.0);
// Deserialize values from the byte data back to the rectangle object
s.deserialize(data, rect);
System.out.println(rect.getX());
'''Example:''' File accessor, create
RecordType type = Datatypes.getDatatype( Rectangle2D.Double.class );
// Create a new file and initialize it with rectangle type, and open file accessor
FileRecordAccessor fa = Accessors.createFile( file, type );
// Write the first field (x)
fa.setFieldValue(0, Bindings.DOUBLE, 5.0);
fa.close();
'''Example:''' File accessor, open
// Open an accessor to an existing binary file
FileVariantAccessor fa = Accessors.openAccessor(file);
RecordAccessor ra = fa.getContentAccessor();
// Read the first field (x)
Double x = (Double) ra.getFieldValue(0, Bindings.DOUBLE);
fa.close();
'''Example:''' Java Accessor
Binding binding = Bindings.getBinding(Rectangle2D.Double.class);
Rectangle2D rect = new Rectangle2D.Double(0,0, 10, 10);
// Open accessor to rectangle
RecordAccessor ra = Accessors.getAccessor(binding, rect);
// Set rectangle's first field (x) to 5.0
ra.setFieldValue(0, Bindings.DOUBLE, 5.0);
System.out.println( rect.getX() );
==Accessor Reference==
Accessors can be opened to a sub-nodes with AccessorReference or by calling getAccessor. AccessorReference is a string of instances, either accessor type specific of LabelReferences.
ChildReference ref = ChildReference.compile(
new NameReference("node"),
new ComponentReference()
);
Accessor child = accessor.getComponent( ref );
ChildReference ref = ChildReference.compile(
new LabelReference("node"),
new LabelReference("v")
);
Accessor child = accessor.getComponent( ref );
ChildReference ref = ChildReference.create("n-node/v");
Accessor child = accessor.getComponent( ref );
ChildReference ref = ChildReference.create("node/v");
Accessor child = accessor.getComponent( ref );
VariantAccessor va = recordAccessor.getFieldAccessor("node");
Accessor child = va.getValueAccessor();
==Listening mechanism==
Accessor offers a monitoring mechanism for the data model.
There is an [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/interestset/InterestSet.java|InterestSet]] that is a description of a sub-tree that is to be monitored of the data model.
[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/event/Event.java|Events]] are objects that spawned on changes to the data model. Each event object is annotated with [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/accessor/reference/|reference path]] that is in relation to the node where the listener was placed.
Accessor Listeners use [[EventThread Pattern]] pattern.
=Utilities=
*[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/Datatypes.java|Datatypes]] is a facade class that has functions for handling Datatypes.
*[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/Bindings.java|Bindings]] is a facade class that has functions for handling Bindings.
*[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/Accessors.java|Accessors]] is a facade class that has functions for handling Accessors.
*[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/Files.java|Files]] has Read, Write and accessor functions.
*[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/Units.java|Units]] is a facade class that has functions for handling Engineering Units.
*[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/Methods.java|Methods]] has Methods, Interfaces and RPC utility functions.
*[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/util/binary/RandomAccessBinary.java|RandomAccessBinary]] is a interface for byte handling operations. In addition to basic primitive reading & writing, there are methods for grow, shrink, insert and remove.
**[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/util/binary/BinaryFile.java|BinaryFile]] and [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/util/binary/BinaryMemory.java|BinaryMemory]] are corresponding file and memory implementations.
**[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/util/binary/Blob.java|Blob]] is an implementation that represents a sub-region of a RandomAccessBinary.
==Interface Types==
There are interfaces, method types and method type definitions.
Interface type describes a software interface. It is a collection of methods type definitions.
Method type is an unnamed function with the following properties : Response Type, Request Type and ErrorType; where Response Type is any Data Type, Request Type is a Record and Error Type is an Union.
Method type definition is nominal method description.
The respective Java classes are:
*[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/method/Interface.java|Interface.java]]
*[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/method/MethodTypeDefinition.java|MethodTypeDefinition.java]]
*[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/method/MethodType.java|MethodType.java]]
In java InterfaceType description can be created with one of the following methods:
* Implementing InterfaceType
* Reading an Java Interface Class using reflection
Interface it = new Interface( ... methodDefinitions );
Interface it = getInterface( MyInterface.class );
[[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/method/MethodInterface.java|MethodInterface.java]] is a binding of an
Java Instance and an Interface Type. It decouples the method invocation from the object.
MethodInterface can be created with the following methods:
* Implementation
* Reflection
MethodInterface mi = new MethodInterface() {...}
MethodInterface mi = Datatypes.bindInterface( MyInterface.class, myObject );
Utilities Datatypes.createProxy() and Datatypes.bindInterface() adapt between MethodInterface and Java Instance.
MethodInterface mi = Datatypes.bindInterface( MyInterface.class, myObject );
MyInterface myObject = Datatypes.createProxy( MyInterface.class, mi );
==Remote Procedure Call==
Utilities [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/method/Server.java|Server.java]] and [[svn:foundation/databoard/trunk/org.simantics.databoard/src/org/simantics/databoard/method/Client.java|Client.java]] put MethodInterface over TCP Socket.
Server myServer = new Server(8192, mi);
MethodInterface mi = new Client("localhost", 8192);
MethodInterface with Server and Client together forms a Remote Procedure Call (RPC) mechanism.
public interface MyInterface { String helloWorld(String msg); }
[Server]
MethodInterface mi = Methods.bindInterface( MyInterface.class, myObject );
Server myServer = new Server(8192, mi);
[Client]
MethodInterface mi = new Client("localhost", 8192);
MyInterface myObject = Methods.createProxy( MyInterface.class, mi );
[[Category: Data management & Experiment Control]]