Class NodeSelector
- java.lang.Object
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- org.apache.commons.configuration2.tree.NodeSelector
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public class NodeSelector extends Object
A class for selecting a specific node based on a key or a set of keys.
An instance of this class is initialized with the key of a node. It is also possible to concatenate multiple keys - e.g. if a sub key is to be constructed from another sub key.
NodeSelectorprovides theselect()method which evaluates the wrapped keys on a specified root node and returns the resulting unique target node. The class expects that the key(s) stored in an instance select exactly one target node. If this is not the case, result is null indicating that the selection criteria are not sufficient.Implementation node: Instances of this class are immutable. They can be shared between arbitrary components.
- Since:
- 2.0
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Constructor Summary
Constructors Constructor Description NodeSelector(String key)Creates a new instance ofNodeSelectorand initializes it with the key to the target node.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description booleanequals(Object obj)Compares this object with another one.inthashCode()Returns a hash code for this object.ImmutableNodeselect(ImmutableNode root, NodeKeyResolver<ImmutableNode> resolver, NodeHandler<ImmutableNode> handler)Applies thisNodeSelectoron the specified root node.NodeSelectorsubSelector(String subKey)Creates a subNodeSelectorobject which uses the key(s) of this selector plus the specified key as selection criteria.StringtoString()Returns a string representation for this object.
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Constructor Detail
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NodeSelector
public NodeSelector(String key)
Creates a new instance ofNodeSelectorand initializes it with the key to the target node.- Parameters:
key- the key
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Method Detail
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select
public ImmutableNode select(ImmutableNode root, NodeKeyResolver<ImmutableNode> resolver, NodeHandler<ImmutableNode> handler)
Applies thisNodeSelectoron the specified root node. This method applies the selection criteria stored in this object and tries to determine a single target node. If this is successful, the target node is returned. Otherwise, result is null.- Parameters:
root- the root node on which to apply this selectorresolver- theNodeKeyResolverhandler- theNodeHandler- Returns:
- the selected target node or null
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subSelector
public NodeSelector subSelector(String subKey)
Creates a subNodeSelectorobject which uses the key(s) of this selector plus the specified key as selection criteria. This is useful when another selection is to be performed on the results of a first selector.- Parameters:
subKey- the additional key for the sub selector- Returns:
- the sub
NodeSelectorinstance
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equals
public boolean equals(Object obj)
Compares this object with another one. Two instances ofNodeSelectorare considered equal if they have the same keys as selection criteria.
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hashCode
public int hashCode()
Returns a hash code for this object.
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