Package org.apache.commons.configuration2.tree

Class ImmutableNode

java.lang.Object
org.apache.commons.configuration2.tree.ImmutableNode
All Implemented Interfaces:
Iterable<ImmutableNode>
public final class ImmutableNode extends Object implements Iterable<ImmutableNode>

An immutable default implementation for configuration nodes.

This class is used for an in-memory representation of hierarchical configuration data. It stores typical information like a node name, a value, child nodes, or attributes.

After their creation, instances cannot be manipulated. There are methods for updating properties, but these methods return new ImmutableNode instances. Instances are created using the nested Builder class.

Since:
2.0

  • Field Details

    • nodeName

      private final String nodeName
      The name of this node.

    • value

      private final Object value
      The value of this node.

    • children

      private final List<ImmutableNode> children
      A collection with the child nodes of this node.

    • attributes

      private final Map<String,Object> attributes
      A map with the attributes of this node.

  • Constructor Details

    • ImmutableNode

      private ImmutableNode(ImmutableNode.Builder b)
      Creates a new instance of ImmutableNode from the given Builder object.
      Parameters:
      b - the Builder

  • Method Details

    • checkChildNode

      private static void checkChildNode(ImmutableNode child)
      Checks whether the given child node is not null. This check is done at multiple places to ensure that newly added child nodes are always defined.
      Parameters:
      child - the child node to be checked
      Throws:
      IllegalArgumentException - if the child node is null

    • addChild

      public ImmutableNode addChild(ImmutableNode child)
      Creates a new ImmutableNode instance which is a copy of this object, but has the given child node added.
      Parameters:
      child - the child node to be added (must not be null)
      Returns:
      the new node with the child node added
      Throws:
      IllegalArgumentException - if the child node is null

    • createWithBasicProperties

      private ImmutableNode createWithBasicProperties(ImmutableNode.Builder builder)
      Initializes the given builder with basic properties (node name and value) and returns the newly created node. This is a helper method for updating a node when only children or attributes are affected.
      Parameters:
      builder - the already prepared builder
      Returns:
      the newly created node

    • createWithNewAttributes

      private ImmutableNode createWithNewAttributes(Map<String,Object> newAttrs)
      Creates a new ImmutableNode instance with the same properties as this object, but with the given new attributes.
      Parameters:
      newAttrs - the new attributes
      Returns:
      the new node instance

    • getAttributes

      public Map<String,Object> getAttributes()
      Gets a map with the attributes of this node. This map cannot be modified.
      Returns:
      a map with this node's attributes

    • getChildren

      public List<ImmutableNode> getChildren()
      Gets a list with the children of this node. This list cannot be modified.
      Returns:
      a list with the child nodes

    • getChildren

      public List<ImmutableNode> getChildren(String name)
      Returns a list with the children of this node.
      Parameters:
      name - the node name to find
      Returns:
      a list with the child nodes

    • getNodeName

      public String getNodeName()
      Gets the name of this node.
      Returns:
      the name of this node

    • getValue

      public Object getValue()
      Gets the value of this node.
      Returns:
      the value of this node

    • iterator

      public Iterator<ImmutableNode> iterator()
      Specified by:
      iterator in interface Iterable<ImmutableNode>
      Returns:
      An iterator of child nodes.
      Since:
      2.8.0

    • removeAttribute

      public ImmutableNode removeAttribute(String name)
      Returns a new ImmutableNode instance which is a copy of this object, but with the specified attribute removed. If there is no attribute with the given name, the same node instance is returned.
      Parameters:
      name - the name of the attribute
      Returns:
      the new node without this attribute

    • removeChild

      public ImmutableNode removeChild(ImmutableNode child)
      Returns a new ImmutableNode instance which is a copy of this object, but with the given child node removed. If the child node does not belong to this node, the same node instance is returned.
      Parameters:
      child - the child node to be removed
      Returns:
      the new node with the child node removed

    • replaceChild

      public ImmutableNode replaceChild(ImmutableNode oldChild, ImmutableNode newChild)
      Returns a new ImmutableNode instance which is a copy of this object, but with the given child replaced by the new one. If the child to be replaced cannot be found, the same node instance is returned.
      Parameters:
      oldChild - the child node to be replaced
      newChild - the replacing child node (must not be null)
      Returns:
      the new node with the child replaced
      Throws:
      IllegalArgumentException - if the new child node is null

    • replaceChildren

      public ImmutableNode replaceChildren(Collection<ImmutableNode> newChildren)
      Returns a new ImmutableNode instance which is a copy of this object, but with the children replaced by the ones in the passed in collection. With this method all children can be replaced in a single step. For the collection the same rules apply as for ImmutableNode.Builder.addChildren(Collection).
      Parameters:
      newChildren - the collection with the new children (may be null)
      Returns:
      the new node with replaced children

    • setAttribute

      public ImmutableNode setAttribute(String name, Object value)
      Returns a new ImmutableNode instance which is a copy of this object, but with the specified attribute set to the given value. If an attribute with this name does not exist, it is created now. Otherwise, the new value overrides the old one.
      Parameters:
      name - the name of the attribute
      value - the attribute value
      Returns:
      the new node with this attribute

    • setAttributes

      public ImmutableNode setAttributes(Map<String,?> newAttributes)
      Returns a new ImmutableNode instance which is a copy of this object, but with all attributes added defined by the given map. This method is analogous to setAttribute(String, Object), but all attributes in the given map are added. If the map is null or empty, this method has no effect.
      Parameters:
      newAttributes - the map with attributes to be added
      Returns:
      the new node with these attributes

    • setName

      public ImmutableNode setName(String name)
      Creates a new ImmutableNode instance which is a copy of this object with the name changed to the passed in value.
      Parameters:
      name - the name of the newly created node
      Returns:
      the new node with the changed name

    • setValue

      public ImmutableNode setValue(Object newValue)
      Creates a new ImmutableNode instance which is a copy of this object with the value changed to the passed in value.
      Parameters:
      newValue - the value of the newly created node
      Returns:
      the new node with the changed value

    • stream

      public Stream<ImmutableNode> stream()
      Returns a sequential Stream with this node as its source.
      Returns:
      a sequential Stream over the elements in this node.
      Since:
      2.9.0

    • toString

      public String toString()
      Overrides:
      toString in class Object