org.simantics.databoard.accessor.java
Class JavaRecord

java.lang.Object
  extended by org.simantics.databoard.accessor.java.JavaObject
      extended by org.simantics.databoard.accessor.java.JavaRecord
All Implemented Interfaces:
Accessor, ParametrisedAccessor, RecordAccessor

public class JavaRecord
extends JavaObject
implements RecordAccessor

Accessor to a Java Object of Record Type.

Author:
Toni Kalajainen

Nested Class Summary
 
Nested classes/interfaces inherited from interface org.simantics.databoard.accessor.Accessor
Accessor.Listener
 
Constructor Summary
JavaRecord(Accessor parent, RecordBinding binding, java.lang.Object object, AccessorParams params)
           
 
Method Summary
 void addListener(Accessor.Listener listener, InterestSet interestSet, AccessorReference path)
          Place a listener to an accessor node.
 int count()
          Get the number of fields in the record
<T extends Accessor>
T
getAccessor(AccessorReference reference)
          Get an accessor to a sub-container.
 RecordBinding getBinding()
           
<T extends Accessor>
T
getFieldAccessor(int index)
          Get an accessor to a field.
<T extends Accessor>
T
getFieldAccessor(java.lang.String fieldName)
          Get an accessor to a field.
 java.lang.Object getFieldValue(int index, Binding fieldBinding)
          Get field value
 void removeListener(Accessor.Listener listener)
          Remove a listener.
 void setFieldValue(int index, Binding binding, java.lang.Object value)
          Set field value.
 void setValue(Binding binding, java.lang.Object newValue)
          Set a complete new value to the data container.
 RecordType type()
          Get structural represtentation of the accessor presented in databoard's type system.
 
Methods inherited from class org.simantics.databoard.accessor.java.JavaObject
apply, createAccessor, createSubAccessor, getEmitter, getObject, getParams, getReadLock, getValue, getWriteLock, notifyValueChanged, toString
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.simantics.databoard.accessor.Accessor
apply, getValue
 

Constructor Detail

JavaRecord

public JavaRecord(Accessor parent,
                  RecordBinding binding,
                  java.lang.Object object,
                  AccessorParams params)
           throws AccessorConstructionException
Throws:
AccessorConstructionException
Method Detail

getBinding

public RecordBinding getBinding()
Overrides:
getBinding in class JavaObject

type

public RecordType type()
Description copied from interface: Accessor
Get structural represtentation of the accessor presented in databoard's type system.

Specified by:
type in interface Accessor
Specified by:
type in interface RecordAccessor
Overrides:
type in class JavaObject
Returns:
type description

count

public int count()
Description copied from interface: RecordAccessor
Get the number of fields in the record

Specified by:
count in interface RecordAccessor
Returns:
field count

getFieldAccessor

public <T extends Accessor> T getFieldAccessor(java.lang.String fieldName)
                                    throws AccessorConstructionException
Description copied from interface: RecordAccessor
Get an accessor to a field. The return value becomes invalid if a new value is assigned with RecordAccessor.setFieldValue(int, Binding, Object).

Specified by:
getFieldAccessor in interface RecordAccessor
Returns:
accessor to the field
Throws:
AccessorConstructionException

getFieldAccessor

public <T extends Accessor> T getFieldAccessor(int index)
                                    throws AccessorConstructionException
Description copied from interface: RecordAccessor
Get an accessor to a field. The return value becomes invalid if a new value is assigned with RecordAccessor.setFieldValue(int, Binding, Object).

Specified by:
getFieldAccessor in interface RecordAccessor
Returns:
accessor to the field
Throws:
AccessorConstructionException

getFieldValue

public java.lang.Object getFieldValue(int index,
                                      Binding fieldBinding)
                               throws AccessorException
Description copied from interface: RecordAccessor
Get field value

Specified by:
getFieldValue in interface RecordAccessor
Returns:
the value of the field
Throws:
AccessorException

setFieldValue

public void setFieldValue(int index,
                          Binding binding,
                          java.lang.Object value)
                   throws AccessorException
Description copied from interface: RecordAccessor
Set field value. Writing the current value again may not emit an event. This is implementation specific.

Specified by:
setFieldValue in interface RecordAccessor
Parameters:
index - field index
Throws:
AccessorException

addListener

public void addListener(Accessor.Listener listener,
                        InterestSet interestSet,
                        AccessorReference path)
                 throws AccessorException
Description copied from interface: Accessor
Place a listener to an accessor node. The listener will be notified for changes in the node/node tree, depending on interest set.

When events are emited and in which thread processed is implementation specific. It is also implementation specific, whether the object can be mutated in the listener or whether it has to be done afterwards.

In many implementations there is a pluggable event handling strategy EventEmitter. The default behaviour is to emit events as they are spawned in the current thread.

There is a reference in each event instance that describes the path from the accessor where listener was placed to the node to which the event applies to.

Listener is attached to the object that holds the value at the time at the of the adding. For example, If a listener is attached to an array of element at index 3, and a new value is inserted at position 2, the listener still monitors the same container, which is now at index 4. The references of incoming the events are modified to have the new index.

Also, if a new value is assigned to the parent of an object that is listened, the listener keeps on monitoring the new value at the same reference. This doesn't apply when a new value is set to a union of different tag, to a variant with a new type, or value is removed from Optional type. In these two cases the listener is invalidated.

See ChangeSet is an implementation that collects events.

Specified by:
addListener in interface Accessor
Overrides:
addListener in class JavaObject
path - path to the accessor or null. This is used in the events the accessor produces
Throws:
AccessorException
See Also:
collects events

removeListener

public void removeListener(Accessor.Listener listener)
                    throws AccessorException
Description copied from interface: Accessor
Remove a listener. If the listener is added multiple times, the last one added is removed.

Specified by:
removeListener in interface Accessor
Overrides:
removeListener in class JavaObject
Throws:
AccessorException

getAccessor

public <T extends Accessor> T getAccessor(AccessorReference reference)
                               throws AccessorConstructionException
Description copied from interface: Accessor
Get an accessor to a sub-container. If one already exists, the same is returned, otherwise a new is created.

InvalidatedEvent is thrown from the accessor if it is unlinked from the parent hierarchy.

Specified by:
getAccessor in interface Accessor
Parameters:
reference - component reference or null to return _this_ accessor
Returns:
accessor
Throws:
AccessorConstructionException

setValue

public void setValue(Binding binding,
                     java.lang.Object newValue)
              throws AccessorException
Description copied from interface: Accessor
Set a complete new value to the data container. If the new value removes old map entries, array entries, optional value, or changes union or variant value type, it will disengage any existing sub-accessors and send InvalidatedEvent.

Writing the current value again may not emit an event. This is implementation specific.

Write is durable, once a the method returns successfully the value has been stored in the implmentation.

Specified by:
setValue in interface Accessor
Throws:
AccessorException