org.apache.commons.configuration2.tree

Interface NodeKeyResolver<T>

Type Parameters:

T - the type of the nodes supported by this resolver

All Known Implementing Classes:

AbstractHierarchicalConfiguration, AbstractYAMLBasedConfiguration, BaseHierarchicalConfiguration, CombinedConfiguration, DynamicCombinedConfiguration, INIConfiguration, JSONConfiguration, PatternSubtreeConfigurationWrapper, PropertyListConfiguration, SubnodeConfiguration, XMLConfiguration, XMLPropertyListConfiguration, YAMLConfiguration

public interface NodeKeyResolver<T>

Definition of an interface which allows resolving a (property) key for different manipulating operations.

This interface is used when interacting with a node model. It is an abstraction over a concrete ExpressionEngine instance. It also implements some functionality for creating special helper objects for the processing of complex update operations.

Since:

2.0

Method Summary

Modifier and Type	Method and Description
String	nodeKey(T node, Map<T,String> cache, NodeHandler<T> handler) Generates a unique key for the specified node.
NodeAddData<T>	resolveAddKey(T root, String key, NodeHandler<T> handler) Resolves a key of an add operation.
List<QueryResult<T>>	resolveKey(T root, String key, NodeHandler<T> handler) Performs a query for the specified key on the given root node.
List<T>	resolveNodeKey(T root, String key, NodeHandler<T> handler) Performs a query for the specified key on the given root node returning only node results.
NodeUpdateData<T>	resolveUpdateKey(T root, String key, Object newValue, NodeHandler<T> handler) Resolves a key for an update operation.

Method Detail

resolveKey

List<QueryResult<T>> resolveKey(T root,
                                String key,
                                NodeHandler<T> handler)

Performs a query for the specified key on the given root node. This is a thin wrapper over the query() method of an ExpressionEngine.

Parameters:

root - the root node

key - the key to be resolved

handler - the NodeHandler

Returns:

a list with query results

resolveNodeKey

List<T> resolveNodeKey(T root,
                       String key,
                       NodeHandler<T> handler)

Performs a query for the specified key on the given root node returning only node results. Some operations require results of type node and do not support attributes (e.g. for tracking nodes). This operation can be used in such cases. It works like resolveKey(), but filters only for results of type node.

Parameters:

root - the root node

key - the key to be resolved

handler - the NodeHandler

Returns:

a list with the resolved nodes

resolveAddKey

NodeAddData<T> resolveAddKey(T root,
                             String key,
                             NodeHandler<T> handler)

Resolves a key of an add operation. Result is a NodeAddData object containing all information for actually performing the add operation at the specified key.

Parameters:

root - the root node

key - the key to be resolved

handler - the NodeHandler

Returns:

a NodeAddData object to be used for the add operation

resolveUpdateKey

NodeUpdateData<T> resolveUpdateKey(T root,
                                   String key,
                                   Object newValue,
                                   NodeHandler<T> handler)

Resolves a key for an update operation. Result is a NodeUpdateData object containing all information for actually performing the update operation at the specified key using the provided new value object.

Parameters:

root - the root node

key - the key to be resolved

newValue - the new value for the key to be updated; this can be a single value or a container for multiple values

handler - the NodeHandler

Returns:

a NodeUpdateData object to be used for this update operation

nodeKey

String nodeKey(T node,
               Map<T,String> cache,
               NodeHandler<T> handler)

Generates a unique key for the specified node. This method is used if keys have to be generated for nodes received as query results. An implementation must generate a canonical key which is compatible with the current expression engine. The passed in map can be used by an implementation as cache. It is created initially by the caller and then passed in subsequent calls. An implementation may use this to avoid that keys for nodes already encountered have to be generated again.

Parameters:

node - the node in question

cache - a map serving as cache

handler - the NodeHandler

Returns:

a key for the specified node