AbstractNode class

An abstract node in a tree.

AbstractNode has as notion of depth, attachment, and parent, but does not have a model for children.

When a subclass is changing the parent of a child, it should call either parent.adoptChild(child) or parent.dropChild(child) as appropriate. Subclasses can expose an API for manipulating the tree if desired (e.g. a setter for a child property, or an add() method to manipulate a list).

The current parent node is exposed by the parent property.

The current attachment state is exposed by attached. The root of any tree that is to be considered attached should be manually attached by calling attach. Other than that, the attach and detach methods should not be called directly; attachment is managed automatically by the aforementioned adoptChild and dropChild methods.

Subclasses that have children must override attach and detach as described in the documentation for those methods.

Nodes always have a depth greater than their ancestors'. There's no guarantee regarding depth between siblings. The depth of a node is used to ensure that nodes are processed in depth order. The depth of a child can be more than one greater than the depth of the parent, because the depth values are never decreased: all that matters is that it's greater than the parent. Consider a tree with a root node A, a child B, and a grandchild C. Initially, A will have depth 0, B depth 1, and C depth 2. If C is moved to be a child of A, sibling of B, then the numbers won't change. C's depth will still be 2. The depth is automatically maintained by the adoptChild and dropChild methods.

Implemented by

Constructors

AbstractNode()

Properties

attached → bool
Whether this node is in a tree whose root is attached to something. [...]
read-only
depth → int
The depth of this node in the tree. [...]
read-only
owner → Object
The owner for this node (null if unattached). [...]
read-only
parent AbstractNode
The parent of this node in the tree.
read-only
hashCode → int
The hash code for this object. [...]
read-only, inherited
runtimeType → Type
A representation of the runtime type of the object.
read-only, inherited

Methods

adoptChild(AbstractNode child) → void
Mark the given node as being a child of this node. [...]
@mustCallSuper, @protected
attach(Object owner) → void
Mark this node as attached to the given owner. [...]
@mustCallSuper
detach() → void
Mark this node as detached. [...]
@mustCallSuper
dropChild(AbstractNode child) → void
Disconnect the given node from this node. [...]
@mustCallSuper, @protected
redepthChild(AbstractNode child) → void
Adjust the depth of the given child to be greater than this node's own depth. [...]
@protected
redepthChildren() → void
Adjust the depth of this node's children, if any. [...]
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed. [...]
inherited
toString() → String
Returns a string representation of this object.
inherited

Operators

operator ==(dynamic other) → bool
The equality operator. [...]
inherited