org.simantics.databoard.accessor.binary
Class BinaryRecord

java.lang.Object
  extended by org.simantics.databoard.accessor.binary.BinaryObject
      extended by org.simantics.databoard.accessor.binary.BinaryRecord
All Implemented Interfaces:
Accessor, CloseableAccessor, FileAccessor, FileRecordAccessor, ParametrisedAccessor, RecordAccessor

public class BinaryRecord
extends BinaryObject
implements RecordAccessor, FileRecordAccessor

Accessor to a Binary Record. Get and set field operations scan the file. File operations are most efficient if field-specific subaccessors are acquired and used instead of setFieldValue(int, Binding, Object) and getFieldValue(int, Binding).

Note, To increase the random access performance of the record, create sub-accessors of its fields.

Author:
Toni Kalajainen

Nested Class Summary
 
Nested classes/interfaces inherited from interface org.simantics.databoard.accessor.Accessor
Accessor.Listener
 
Constructor Summary
BinaryRecord(BinaryObject parent, Blob blob, RecordType type, AccessorParams params)
           
 
Method Summary
 void addListener(Accessor.Listener listener, InterestSet interestSet, ChildReference path)
          Place a listener to an accessor node.
 int count()
          Get the number of fields in the record
<T extends Accessor>
T
getComponent(ChildReference reference)
          Open an accessor to a child.
<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 fieldBinding, java.lang.Object value)
          Set field value.
 void setFieldValueNoflush(int index, Binding cb, java.lang.Object cv)
           
 void setValueNoflush(Binding binding, java.lang.Object newValue)
          Write a new value and don't flush the buffer
 RecordType type()
          Get structural represtentation of the accessor presented in databoard's type system.
 
Methods inherited from class org.simantics.databoard.accessor.binary.BinaryObject
apply, close, createAccessor, file, flush, getBinary, getEmitter, getParams, getReadLock, getSource, getValue, getValue, getWriteLock, setValue, toString
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.simantics.databoard.accessor.file.FileAccessor
close, file, flush
 
Methods inherited from interface org.simantics.databoard.accessor.Accessor
apply, getValue, getValue, setValue
 

Constructor Detail

BinaryRecord

public BinaryRecord(BinaryObject parent,
                    Blob blob,
                    RecordType type,
                    AccessorParams params)
             throws AccessorConstructionException
Throws:
AccessorConstructionException
Method Detail

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 BinaryObject
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 fieldBinding,
                          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

setFieldValueNoflush

public void setFieldValueNoflush(int index,
                                 Binding cb,
                                 java.lang.Object cv)
                          throws AccessorException
Specified by:
setFieldValueNoflush in interface FileRecordAccessor
Throws:
AccessorException

addListener

public void addListener(Accessor.Listener listener,
                        InterestSet interestSet,
                        ChildReference 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 BinaryObject
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 BinaryObject
Throws:
AccessorException

getComponent

public <T extends Accessor> T getComponent(ChildReference reference)
                                throws AccessorConstructionException
Description copied from interface: Accessor
Open an accessor to a child. If one already exists, the existing is returned, otherwise a new is created. Child accessors are often remembered with weak reference.

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

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

setValueNoflush

public void setValueNoflush(Binding binding,
                            java.lang.Object newValue)
                     throws AccessorException
Description copied from class: BinaryObject
Write a new value and don't flush the buffer

Specified by:
setValueNoflush in interface FileAccessor
Specified by:
setValueNoflush in class BinaryObject
Throws:
AccessorException