Package 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 Details

    • 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

    • 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

    • 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

    • 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