com.vaadin.data
Interface Buffered

All Superinterfaces:

java.io.Serializable

All Known Subinterfaces:

BufferedValidatable, Field<T>

All Known Implementing Classes:

AbstractField, AbstractSelect, AbstractTextField, CheckBox, ComboBox, CustomField, DateField, Form, InlineDateField, ListSelect, NativeSelect, OptionGroup, PasswordField, PopupDateField, ProgressBar, ProgressIndicator, RichTextArea, Select, Slider, Table, TextArea, TextField, Tree, TreeTable, TwinColSelect

public interface Buffered
extends java.io.Serializable

Defines the interface to commit and discard changes to an object, supporting buffering.

In buffered mode the initial value is read from the data source and then buffered. Any subsequential writes or reads will be done on the buffered value. Calling commit() will write the buffered value to the data source while calling discard() while discard the buffered value and re-read the value from the data source.

In non-buffered mode the value is always read directly from the data source. Any write is done directly to the data source with no buffering in between. Reads are also done directly from the data source. Calling commit() or discard() in this mode is efficiently a no-op.

Since:

3.0

Author:

Vaadin Ltd.

Nested Class Summary

static class

Buffered.SourceException An exception that signals that one or more exceptions occurred while a buffered object tried to access its data source or if there is a problem in processing a data source.

Method Summary

void	commit() Updates all changes since the previous commit to the data source.
void	discard() Discards all changes since last commit.
boolean	isBuffered() Checks the buffered mode
boolean	isModified() Tests if the value stored in the object has been modified since it was last updated from the data source.
void	setBuffered(boolean buffered) Sets the buffered mode to the specified status.

Method Detail

commit

void commit()
            throws Buffered.SourceException,
                   Validator.InvalidValueException

Updates all changes since the previous commit to the data source. The value stored in the object will always be updated into the data source when commit is called.

Throws:

Buffered.SourceException - if the operation fails because of an exception is thrown by the data source. The cause is included in the exception.

Validator.InvalidValueException - if the operation fails because validation is enabled and the values do not validate

discard

void discard()
             throws Buffered.SourceException

Discards all changes since last commit. The object updates its value from the data source.

Throws:

Buffered.SourceException - if the operation fails because of an exception is thrown by the data source. The cause is included in the exception.

setBuffered

void setBuffered(boolean buffered)

Sets the buffered mode to the specified status.

When in buffered mode, an internal buffer will be used to store changes until commit() is called. Calling discard() will revert the internal buffer to the value of the data source.

When in non-buffered mode both read and write operations will be done directly on the data source. In this mode the commit() and discard() methods serve no purpose.

Parameters:

buffered - true if buffered mode should be turned on, false otherwise

Since:

7.0

isBuffered

boolean isBuffered()

Checks the buffered mode

Returns:

true if buffered mode is on, false otherwise

Since:

7.0

isModified

boolean isModified()

Tests if the value stored in the object has been modified since it was last updated from the data source.

Returns:

true if the value in the object has been modified since the last data source update, false if not.