Package org.apache.commons.configuration2.tree

Class QueryResult<T>

java.lang.Object
org.apache.commons.configuration2.tree.QueryResult<T>
Type Parameters:
T - the type of the result nodes
public final class QueryResult<T> extends Object

A data class representing a single query result produced by an ExpressionEngine.

When passing a key to the query() method of ExpressionEngine the result can be a set of nodes or attributes - depending on the key. This class can represent both types of results. The aim is to give a user of ExpressionEngine all information needed for evaluating the results returned.

Implementation note: Instances are immutable. They are created using the static factory methods.

Since:
2.0

  • Method Details

    • createNodeResult

      public static <T> QueryResult<T> createNodeResult(T resultNode)
      Creates a QueryResult instance representing the specified result node.
      Type Parameters:
      T - the type of the result node
      Parameters:
      resultNode - the result node
      Returns:
      the newly created instance

    • createAttributeResult

      public static <T> QueryResult<T> createAttributeResult(T parentNode, String attrName)
      Creates a QueryResult instance representing an attribute result. An attribute result consists of the node the attribute belongs to and the attribute name. (The value can be obtained based on this information.)
      Type Parameters:
      T - the type of the parent node
      Parameters:
      parentNode - the node which owns the attribute
      attrName - the attribute name
      Returns:
      the newly created instance

    • getNode

      public T getNode()
      Gets the node referenced by this object. Depending on the result type, this is either the result node or the parent node of the represented attribute.
      Returns:
      the referenced node

    • getAttributeName

      public String getAttributeName()
      Gets the name of the attribute. This method is defined only for results of type attribute.
      Returns:
      the attribute name

    • isAttributeResult

      public boolean isAttributeResult()
      Returns a flag whether this is a result of type attribute. If result is true, the attribute name and value can be queried. Otherwise, only the result node is available.
      Returns:
      true for an attribute result, false otherwise

    • getAttributeValue

      public Object getAttributeValue(NodeHandler<T> handler)
      Gets the attribute value if this is an attribute result. If this is not an attribute result, an exception is thrown.
      Parameters:
      handler - the NodeHandler
      Returns:
      the attribute value
      Throws:
      IllegalStateException - if this is not an attribute result

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Compares this object with another one. Two instances of QueryResult are considered equal if they are of the same result type and have the same properties.
      Overrides:
      equals in class Object
      Parameters:
      obj - the object to compare to
      Returns:
      a flag whether these objects are equal

    • toString

      public String toString()
      Returns a string representation of this object. Depending on the result type either the result node or the parent node and the attribute name are contained in this string.
      Overrides:
      toString in class Object
      Returns:
      a string for this object