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 Summary

Modifier and Type	Method and Description
static <T> QueryResult<T>	createAttributeResult(T parentNode, String attrName) Creates a QueryResult instance representing an attribute result.
static <T> QueryResult<T>	createNodeResult(T resultNode) Creates a QueryResult instance representing the specified result node.
boolean	equals(Object obj) Compares this object with another one.
String	getAttributeName() Returns the name of the attribute.
Object	getAttributeValue(NodeHandler<T> handler) Returns the attribute value if this is an attribute result.
T	getNode() Returns the node referenced by this object.
int	hashCode()
boolean	isAttributeResult() Returns a flag whether this is a result of type attribute.
String	toString() Returns a string representation of this object.

Methods inherited from class java.lang.Object

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

Method Detail

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()

Returns 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()

Returns 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)

Returns 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