net.sourceforge.esw.properties
Class DefaultPropertySource

java.lang.Object
  |
  +--net.sourceforge.esw.util.SupportObject
        |
        +--net.sourceforge.esw.graph.Node
              |
              +--net.sourceforge.esw.properties.DefaultPropertySource

All Implemented Interfaces:

java.lang.Cloneable, ICloneable, INode, IPropertySource, ISupportObject, java.io.Serializable

public class DefaultPropertySource

extends Node

implements IPropertySource

Default implementation of IPropertySource.

Properties are any persistent data source that parameterizes behavior of a running application. That data source could be XML, a relational database, or a java.util.Properties file..

For the ESW framework, properties are desinged to be aggregate. That is, multiple properites should be able to be searched against at a specific ranking. This allows many properity sources to be considered as one property source. It also allows one property source to override the properies found in another property source by holding a higher rank in the aggregate property set. See IPropertyAggregator for form information.

To load properties from their data source, call the load method.

Properties can be read-only or writable. The setWriteable and isWriteable methods determine whether an IPropertySource instance is writeable. Writeable indicates that a property cannot be saved, not that it cannot be added to this IPropertySource instance.

If the properties represented by this IPropertySource instance are writable, then the save method saves the properties to the represented property source.

To allow easy access to Properties, this IPropertySource implementor extends the INode interface.

To create an new instance of an IPropertySource and add it to the default IPropertyAggregator instance, see PropertyUtil.createXYZPropertySource().

To create a new instance of an IPropertySource independant of an IPropertyAggregator instance, see PropertyFactory.createPropertySource().

Examples:

    // To create a file based XML Property Source and add it to the default
    // IPropertyAggregator instance at the first, or highest, rank:
    PropertyUtil.createFileXMLPropertySource( "MyFilename.xml", 1 );

    // To create an URL based XML Property Source and add it to the default
    // IPropertyAggregator instance at the first, or highest, rank:
    PropertyUtil.createURLXMLPropertySource( "www.somewhere-that-does-not-exist.com", 1 );

    // To create an IPropertySource independant of the IPropertyAggregator:
    IPropertSource source = PropertyFactory.createPropertySource( getMyTransducer() );
 

See Also:

IPropertyAggregator, PropertyManager, PropertyFactory, Serialized Form

Field Summary

protected boolean	bWriteable States whether this DefaultPropertySource instance is a writeable IPropertySource instance.
protected ITransducer	transducer The ITransducer instance for this DefaultPropertySource instance.

Fields inherited from class net.sourceforge.esw.graph.Node

list, map, parents, value

Fields inherited from class net.sourceforge.esw.util.SupportObject

id, properties, propertyChildren, propertyListeners, vetoableChildren, vetoableListeners

Constructor Summary

protected	DefaultPropertySource(ITransducer aTransducer) Creates a new DefaultPropertySource instance.
protected	DefaultPropertySource(ITransducer aTransducer, boolean bWriteable) Creates a new DefaultPropertySource instance with the specified writeable setting.

Method Summary

boolean	isWriteable() Returns whether this IPropertySource instance is a writeable IPropertySource instance.
void	load() Loads properties from the properties source represented by this IPropertySource instance.
void	save() Saves all modified properties to the properties source represented by this IPropertySource instance.
void	setWriteable(boolean aWriteable) Sets whether this IPropertySource instance is a writeable IPropertySource instance.

Methods inherited from class net.sourceforge.esw.graph.Node

acceptVisitor, add, add, addParent, clear, clone, containsID, equals, get, get, getList, getParents, getValue, hashCode, hashCodeForNode, isEmpty, iterator, nodesEqual, remove, removeParent, setValue, size, toString

Methods inherited from class net.sourceforge.esw.util.SupportObject

addPropertyChangeListener, addPropertyChangeListener, addVetoableChangeListener, addVetoableChangeListener, firePropertyChange, firePropertyChange, fireVetoableChange, fireVetoableChange, getID, getProperty, getPropertySize, propertyKeys, removeProperty, removePropertyChangeListener, removePropertyChangeListener, removeVetoableChangeListener, removeVetoableChangeListener, setID, setProperty

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface net.sourceforge.esw.graph.INode

acceptVisitor, add, add, addParent, clear, containsID, get, get, getList, getParents, getValue, isEmpty, iterator, remove, removeParent, setValue, size

Methods inherited from interface net.sourceforge.esw.util.ISupportObject

addPropertyChangeListener, addPropertyChangeListener, addVetoableChangeListener, addVetoableChangeListener, firePropertyChange, firePropertyChange, fireVetoableChange, fireVetoableChange, getID, getProperty, getPropertySize, propertyKeys, removeProperty, removePropertyChangeListener, removePropertyChangeListener, removeVetoableChangeListener, removeVetoableChangeListener, setID, setProperty

Methods inherited from interface net.sourceforge.esw.util.ICloneable

clone

Field Detail

bWriteable

protected boolean bWriteable

States whether this DefaultPropertySource instance is a writeable IPropertySource instance.

transducer

protected ITransducer transducer

The ITransducer instance for this DefaultPropertySource instance.

Constructor Detail

DefaultPropertySource

protected DefaultPropertySource(ITransducer aTransducer)

Creates a new DefaultPropertySource instance. By default, this DefaultPropertySource instance is writable.

Parameters:

aTransducer - the ITransducer instance used by this DefaultPropertySource instance to load or save Properties.

DefaultPropertySource

protected DefaultPropertySource(ITransducer aTransducer,
                                boolean bWriteable)

Creates a new DefaultPropertySource instance with the specified writeable setting.

Parameters:

aTransducer - the ITransducer instance used by this DefaultPropertySource instance to load or save Properties.

aWriteable - if true, this IPropertySource instance will be created as being writable, otherwise, this IPropertySource instance will be read-only.

Method Detail

isWriteable

public boolean isWriteable()

Returns whether this IPropertySource instance is a writeable IPropertySource instance.

Specified by:

isWriteable in interface IPropertySource

Returns:

true if this IPropertySource instance is writeable, false if not.

setWriteable

public void setWriteable(boolean aWriteable)

Sets whether this IPropertySource instance is a writeable IPropertySource instance.

Specified by:

setWriteable in interface IPropertySource

Parameters:

aWriteable - if true, then this IPropertySource instance is writeable, false otherwise.

save

public void save()
          throws java.lang.UnsupportedOperationException,
                 java.lang.Exception

Saves all modified properties to the properties source represented by this IPropertySource instance.

Specified by:

save in interface IPropertySource

Throws:

OptionNotSupportedException - if the operation is unsupported.

java.lang.Exception - if an error occurs during the save process.

load

public void load()
          throws java.lang.Exception

Loads properties from the properties source represented by this IPropertySource instance.

Specified by:

load in interface IPropertySource

Throws:

java.lang.Exception - if any error occurs during the load process.