Class ImmutableNode.Builder

java.lang.Object
org.apache.commons.configuration2.tree.ImmutableNode.Builder
Enclosing class:
ImmutableNode

public static final class ImmutableNode.Builder extends Object

A builder class for creating instances of ImmutableNode.

This class can be used to set all properties of an immutable node instance. Eventually call the create() method to obtain the resulting instance.

Implementation note: This class is not thread-safe. It is intended to be used to define a single node instance only.

  • Field Details

    • directChildren

      private final List<ImmutableNode> directChildren
      The direct list of children of the new node.
    • directAttributes

      private final Map<String,Object> directAttributes
      The direct map of attributes of the new node.
    • children

      private List<ImmutableNode> children
      A list for the children of the new node. This list is populated by the addChild() method.
    • attributes

      private Map<String,Object> attributes
      A map for storing the attributes of the new node. This map is populated by addAttribute().
    • name

      private String name
      The name of the node.
    • value

      private Object value
      The value of the node.
  • Constructor Details

    • Builder

      public Builder()
      Creates a new instance of Builder which does not contain any property definitions yet.
    • Builder

      public Builder(int childCount)
      Creates a new instance of Builder and sets the number of expected child nodes. Using this constructor helps the class to create a properly sized list for the child nodes to be added.
      Parameters:
      childCount - the number of child nodes
    • Builder

      private Builder(List<ImmutableNode> dirChildren, Map<String,Object> dirAttrs)
      Creates a new instance of Builder and initializes the children and attributes of the new node. This constructor is used internally by the ImmutableNode class for creating instances derived from another node. The passed in collections are passed directly to the newly created instance; thus they already need to be immutable. (Background is that the creation of intermediate objects is to be avoided.)
      Parameters:
      dirChildren - the children of the new node
      dirAttrs - the attributes of the new node
    • Builder

      private Builder(int childCount, Map<String,Object> dirAttrs)
      Creates a new instance of Builder and initializes the attributes of the new node and prepares the collection for the children. This constructor is used internally by methods of ImmutableNode which update the node and change the children. The new number of child nodes can be passed so that the collection for the new children can be created with an appropriate size.
      Parameters:
      childCount - the expected number of new children
      dirAttrs - the attributes of the new node
  • Method Details

    • name

      public ImmutableNode.Builder name(String n)
      Sets the name of the node to be created.
      Parameters:
      n - the node name
      Returns:
      a reference to this object for method chaining
    • value

      public ImmutableNode.Builder value(Object v)
      Sets the value of the node to be created.
      Parameters:
      v - the value
      Returns:
      a reference to this object for method chaining
    • addChild

      public ImmutableNode.Builder addChild(ImmutableNode c)
      Adds a child node to this builder. The passed in node becomes a child of the newly created node. If it is null, it is ignored.
      Parameters:
      c - the child node (must not be null)
      Returns:
      a reference to this object for method chaining
    • addChildren

      public ImmutableNode.Builder addChildren(Collection<? extends ImmutableNode> children)
      Adds multiple child nodes to this builder. This method works like addChild(ImmutableNode), but it allows setting a number of child nodes at once.
      Parameters:
      children - a collection with the child nodes to be added
      Returns:
      a reference to this object for method chaining
    • addAttribute

      public ImmutableNode.Builder addAttribute(String name, Object value)
      Adds an attribute to this builder. The passed in attribute key and value are stored in an internal map. If there is already an attribute with this name, it is overridden.
      Parameters:
      name - the attribute name
      value - the attribute value
      Returns:
      a reference to this object for method chaining
    • addAttributes

      public ImmutableNode.Builder addAttributes(Map<String,?> attrs)
      Adds all attributes of the given map to this builder. This method works like addAttribute(String, Object), but it allows setting multiple attributes at once.
      Parameters:
      attrs - the map with attributes to be added (may be null
      Returns:
      a reference to this object for method chaining
    • create

      public ImmutableNode create()
      Creates a new ImmutableNode instance based on the properties set for this builder.
      Returns:
      the newly created ImmutableNode
    • createChildren

      List<ImmutableNode> createChildren()
      Creates a list with the children of the newly created node. The list returned here is always immutable. It depends on the way this builder was populated.
      Returns:
      the list with the children of the new node
    • createAttributes

      private Map<String,Object> createAttributes()
      Creates a map with the attributes of the newly created node. This is an immutable map. If direct attributes were set, they are returned. Otherwise an unmodifiable map from the attributes passed to this builder is constructed.
      Returns:
      a map with the attributes for the new node
    • ensureChildrenExist

      private void ensureChildrenExist()
      Ensures that the collection for the child nodes exists. It is created on demand.
    • ensureAttributesExist

      private void ensureAttributesExist()
      Ensures that the map for the attributes exists. It is created on demand.
    • initChildrenCollection

      private void initChildrenCollection(int childCount)
      Creates the collection for child nodes based on the expected number of children.
      Parameters:
      childCount - the expected number of new children
    • filterNull

      private static Collection<? extends ImmutableNode> filterNull(Collection<? extends ImmutableNode> children)
      Filters null entries from the passed in collection with child nodes.
      Parameters:
      children - the collection to be filtered
      Returns:
      the collection with null entries removed