public class SubnodeConfiguration extends BaseHierarchicalConfiguration
A specialized hierarchical configuration class with a node model that uses a tracked node of another node model as its root node.
Configurations of this type are initialized with a special NodeModel
operating on a specific tracked node of the parent configuration and the
corresponding NodeSelector. All property accessor methods are
evaluated relative to this root node. A good use case for a
SubnodeConfiguration is when multiple properties from a specific sub
tree of the whole configuration need to be accessed. Then a
SubnodeConfiguration can be created with the parent node of the
affected sub tree as root node. This allows for simpler property keys and is
also more efficient.
By making use of a tracked node as root node, a SubnodeConfiguration
and its parent configuration initially operate on the same hierarchy of
configuration nodes. So if modifications are performed at the subnode
configuration, these changes are immediately visible in the parent
configuration. Analogously will updates of the parent configuration affect
the SubnodeConfiguration if the sub tree spanned by the
SubnodeConfiguration's root node is involved.
Note that by making use of a NodeSelector the
SubnodeConfiguration is not associated with a physical node instance,
but the selection criteria stored in the selector are evaluated after each
change of the nodes structure. As an example consider that the selector uses
a key with an index into a list element, say index 2. Now if an update occurs
on the underlying nodes structure which removes the first element in this
list structure, the SubnodeConfiguration still references the element
with index 2 which is now another one.
There are also possible changes of the underlying nodes structure which
completely detach the SubnodeConfiguration from its parent
configuration. For instance, the key referenced by the
SubnodeConfiguration could be removed in the parent configuration. If
this happens, the SubnodeConfiguration stays functional; however, it
now operates on a separate node model than its parent configuration. Changes
made by one configuration are no longer visible for the other one (as the
node models have no longer overlapping nodes, there is no way to have a
synchronization here).
When a subnode configuration is created, it inherits the settings of its
parent configuration, e.g. some flags like the
throwExceptionOnMissing flag or the settings for handling list
delimiters) or the expression engine. If these settings are changed later in
either the subnode or the parent configuration, the changes are not visible
for each other. So you could create a subnode configuration, and change its
expression engine without affecting the parent configuration.
Because the SubnodeConfiguration operates on the same nodes structure
as its parent it uses the same Synchronizer instance per default.
This means that locks held on one SubnodeConfiguration also impact
the parent configuration and all of its other SubnodeConfiguration
objects. You should not change this without a good reason! Otherwise, there
is the risk of data corruption when multiple threads access these
configuration concurrently.
From its purpose this class is quite similar to SubsetConfiguration.
The difference is that a subset configuration of a hierarchical configuration
may combine multiple configuration nodes from different sub trees of the
configuration, while all nodes in a subnode configuration belong to the same
sub tree. If an application can live with this limitation, it is recommended
to use this class instead of SubsetConfiguration because creating a
subset configuration is more expensive than creating a subnode configuration.
It is strongly recommended to create SubnodeConfiguration instances
only through the configurationAt() methods of a hierarchical
configuration. These methods ensure that all necessary initializations are
done. Creating instances manually without doing proper initialization may
break some of the functionality provided by this class.
BaseHierarchicalConfiguration.BuilderVisitor| Constructor and Description |
|---|
SubnodeConfiguration(BaseHierarchicalConfiguration parent,
TrackedNodeModel model)
Creates a new instance of
SubnodeConfiguration and initializes it
with all relevant properties. |
| Modifier and Type | Method and Description |
|---|---|
protected NodeModel<ImmutableNode> |
cloneNodeModel()
Creates a clone of the node model.
|
void |
close()
Closes this sub configuration.
|
protected SubnodeConfiguration |
createSubConfigurationForTrackedNode(NodeSelector selector,
InMemoryNodeModelSupport parentModelSupport)
Creates a connected sub configuration based on a selector for a tracked
node.
|
InMemoryNodeModel |
getNodeModel()
Returns the
NodeModel supported by this object. |
BaseHierarchicalConfiguration |
getParent()
Returns the parent configuration of this subnode configuration.
|
InMemoryNodeModel |
getRootNodeModel()
Returns the node model of the root configuration.
|
NodeSelector |
getRootSelector()
Returns the selector to the root node of this configuration.
|
protected NodeSelector |
getSubConfigurationNodeSelector(String key)
Returns the
NodeSelector to be used for a sub configuration based
on the passed in key. |
protected InMemoryNodeModel |
getSubConfigurationParentModel()
Returns the
InMemoryNodeModel to be used as parent model for a
new sub configuration. |
childConfigurationsAt, childConfigurationsAt, configurationAt, configurationAt, configurationsAt, configurationsAt, immutableChildConfigurationsAt, immutableConfigurationAt, immutableConfigurationAt, immutableConfigurationsAt, initSubConfigurationForThisParent, interpolatedConfiguration, subnodeConfigurationChanged, subsetaddNodes, addNodesInternal, addPropertyDirect, addPropertyInternal, clearInternal, clearPropertyDirect, clearTree, clearTreeInternal, clone, containsKeyInternal, fetchNodeList, getExpressionEngine, getKeysInternal, getKeysInternal, getMaxIndex, getMaxIndexInternal, getModel, getPropertyInternal, getRootElementName, getRootElementNameInternal, isEmptyInternal, nodeDefined, nodeKey, resolveAddKey, resolveKey, resolveNodeKey, resolveUpdateKey, setExpressionEngine, setPropertyInternal, sizeInternal, toStringaddErrorLogListener, addProperty, append, beginRead, beginWrite, clear, clearProperty, cloneInterpolator, containsKey, copy, endRead, endWrite, get, get, getArray, getArray, getBigDecimal, getBigDecimal, getBigInteger, getBigInteger, getBoolean, getBoolean, getBoolean, getByte, getByte, getByte, getCollection, getCollection, getConfigurationDecoder, getConversionHandler, getDouble, getDouble, getDouble, getEncodedString, getEncodedString, getFloat, getFloat, getFloat, getInt, getInt, getInteger, getInterpolator, getKeys, getKeys, getList, getList, getList, getList, getListDelimiterHandler, getLogger, getLong, getLong, getLong, getProperties, getProperties, getProperty, getShort, getShort, getShort, getString, getString, getStringArray, getSynchronizer, immutableSubset, initLogger, installInterpolator, interpolate, interpolate, isEmpty, isScalarValue, isThrowExceptionOnMissing, lock, setConfigurationDecoder, setConversionHandler, setDefaultLookups, setInterpolator, setListDelimiterHandler, setLogger, setParentInterpolator, setPrefixLookups, setProperty, setSynchronizer, setThrowExceptionOnMissing, size, unlockaddEventListener, clearErrorListeners, clearEventListeners, copyEventListeners, createErrorEvent, createEvent, fireError, fireEvent, getEventListenerRegistrations, getEventListeners, isDetailEvents, removeEventListener, setDetailEventsequals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, waitaddProperty, clear, clearProperty, getInterpolator, installInterpolator, setInterpolator, setPropertygetSynchronizer, lock, setSynchronizer, unlockcontainsKey, get, get, getArray, getArray, getBigDecimal, getBigDecimal, getBigInteger, getBigInteger, getBoolean, getBoolean, getBoolean, getByte, getByte, getByte, getCollection, getCollection, getDouble, getDouble, getDouble, getEncodedString, getEncodedString, getFloat, getFloat, getFloat, getInt, getInt, getInteger, getKeys, getKeys, getList, getList, getList, getList, getLong, getLong, getLong, getProperties, getProperty, getShort, getShort, getShort, getString, getString, getStringArray, immutableSubset, isEmpty, sizepublic SubnodeConfiguration(BaseHierarchicalConfiguration parent, TrackedNodeModel model)
SubnodeConfiguration and initializes it
with all relevant properties.parent - the parent configurationmodel - the TrackedNodeModel to be used for this configurationIllegalArgumentException - if a required argument is missingpublic BaseHierarchicalConfiguration getParent()
public NodeSelector getRootSelector()
NodeSelector to the root nodepublic void close()
TrackedNodeModel, thus causing the tracked node acting as root
node to be released. Per default, this happens automatically when the
model is claimed by the garbage collector. By calling this method
explicitly, it can be indicated that this configuration is no longer used
and that resources used by it can be freed immediately.public InMemoryNodeModel getNodeModel()
NodeModel supported by this object. This implementation returns the configuration's
NodeModel. It is guarded by the current Synchronizer. This implementation returns the InMemoryNodeModel
used by this configuration. This implementation returns a newly created node model
with the correct root node set. Note that this model is not used for
property access, but only made available to clients that need to
operate on the node structure of this SubnodeConfiguration.
Be aware that the implementation of this method is not very efficient.getNodeModel in interface InMemoryNodeModelSupportgetNodeModel in interface NodeModelSupport<ImmutableNode>getNodeModel in class BaseHierarchicalConfigurationNodeModelpublic InMemoryNodeModel getRootNodeModel()
SubnodeConfiguration instances created from a hierarchical
configuration operate on the same node model, using different nodes as
their local root nodes. With this method the top-level node model can be
obtained. It works even in constellations where a
SubnodeConfiguration has been created from another
SubnodeConfiguration.protected NodeModel<ImmutableNode> cloneNodeModel()
clone(). This implementation creates a new instance of
InMemoryNodeModel, initialized with this configuration's root
node. This has the effect that although the same nodes are used, the
original and copied configurations are independent on each other. This implementation returns a copy of the current node
model with the same settings. However, it has to be ensured that the
track count for the node selector is increased.cloneNodeModel in class BaseHierarchicalConfigurationprotected NodeSelector getSubConfigurationNodeSelector(String key)
NodeSelector to be used for a sub configuration based
on the passed in key. This method is called whenever a sub configuration
is to be created. This base implementation returns a new
NodeSelector initialized with the passed in key. Sub classes may
override this method if they have a different strategy for creating a
selector. This implementation returns a sub selector of the selector
of this configuration.getSubConfigurationNodeSelector in class BaseHierarchicalConfigurationkey - the key of the sub configurationNodeSelector for initializing a sub configurationprotected InMemoryNodeModel getSubConfigurationParentModel()
InMemoryNodeModel to be used as parent model for a
new sub configuration. This method is called whenever a sub configuration
is to be created. This base implementation returns the model of this
configuration. Sub classes with different requirements for the parent
models of sub configurations have to override it. This implementation returns the parent model of the
TrackedNodeModel used by this configuration.getSubConfigurationParentModel in class BaseHierarchicalConfigurationprotected SubnodeConfiguration createSubConfigurationForTrackedNode(NodeSelector selector, InMemoryNodeModelSupport parentModelSupport)
createSubConfigurationForTrackedNode in class BaseHierarchicalConfigurationselector - the NodeSelectorparentModelSupport - the InMemoryNodeModelSupport object for
the parent node modelCopyright © 2001–2020 The Apache Software Foundation. All rights reserved.