Type Parameters:

N - Node class.
```
public interface TreeAdapter<N>
```
Interface giving access to a lightweight directed tree.
Edges are not represented as objects.
It is the responsibility of implementation to ensure that the tree is consistent.

Author:

Damien Carbonne

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`default boolean`	`areRelated(N node1, N node2, Strictness strictness)`
`default boolean`	`areRelatedOrEqual(N node1, N node2)`
`default boolean`	`areStrictlyRelated(N node1, N node2)`
`default boolean`	`areUnrelated(N node1, N node2)`
`default boolean`	`canSetParent(N node, N candidateParent)`	Returns `true` when a node can be attached as a parent of another node.
`Iterable<N>`	`getChildren(N node)`	Returns an Iterable of children nodes.
`default int`	`getDepth(N node)`	Returns the depth of a node.
`default N`	`getFirstCommonAncestor(N node1, N node2)`	Returns the first common ancestor of 2 nodes.
`default int`	`getHeight(N node)`	Returns the height of the tree under a node.
`default int`	`getIndex(N node)`	Returns the index of a child node in its parent's children.
`N`	`getParent(N node)`	Returns the parent node of this node, possibly `null`.
`default N[]`	`getPath(N node)`
`default int[]`	`getQIndex(N node)`	Returns the qualified index of a node.
`default NodeRelativePosition`	`getRelativePosition(N node1, N node2)`	Returns the relative position of 2 nodes.
`default N`	`getRoot(N node)`	Returns the root of a node.
`boolean`	`hasChildren(N node)`	Returns `true` when a node has children.
`default boolean`	`isLeaf(N node)`	Returns `true` when a node is a leaf node.
`default boolean`	`isOver(N node1, N node2, Strictness strictness)`	Returns `true` when a first node is loosely or strictly over a second node.
`default boolean`	`isOverOrEqual(N node1, N node2)`	Returns `true` when a first node is over or equal to a second node.
`default boolean`	`isRoot(N node)`	Returns `true` when a node is a root node.
`default boolean`	`isStrictlyOver(N node1, N node2)`	Returns `true` when a first node is strictly over a second node.
`default boolean`	`isStrictlyUnder(N node1, N node2)`	Returns `true` when a first node is strictly under a second node.
`default boolean`	`isUnder(N node1, N node2, Strictness strictness)`	Returns `true` when a first node is loosely or strictly under a second node.
`default boolean`	`isUnderOrEqual(N node1, N node2)`	Returns `true` when a first node is under or equal to a second node.

- Method Detail
  - getParent
```
N getParent(N node)
```
    Returns the parent node of this node, possibly null.
    
    Parameters:
    
    node - The node. MUST NOT be null.
    
    Returns:
    
    The parent of node, or null.
  - getChildren
```
Iterable<N> getChildren(N node)
```
    Returns an Iterable of children nodes.
    
    Parameters:
    
    node - The node. MUST NOT be null.
    
    Returns:
    
    An Iterable of children nodes.
  - hasChildren
```
boolean hasChildren(N node)
```
    Returns true when a node has children.
    This could be deduced from getChildren(), but may provide a better implementation.
    
    Parameters:
    
    node - The node. MUST NOT be null.
    
    Returns:
    
    true when node has children.
  - getRoot
```
default N getRoot(N node)
```
    Returns the root of a node.
    It is the highest ancestor that has no parent.
    It may be the node itself (when it is a root).
    
    Parameters:
    
    node - The node. MUST NOT be null.
    
    Returns:
    
    The root of node.
  - isRoot
```
default boolean isRoot(N node)
```
    Returns true when a node is a root node.
    It is non null and has a null parent.
    
    Parameters:
    
    node - The node.
    
    Returns:
    
    true when node is a root.
  - isLeaf
```
default boolean isLeaf(N node)
```
    Returns true when a node is a leaf node.
    It is non null and has no children.
    
    Parameters:
    
    node - The node.
    
    Returns:
    
    true when node is a leaf.
  - getDepth
```
default int getDepth(N node)
```
    Returns the depth of a node.
    It is the number of edges between the node and the root.
    Depth of root node is 0.
    
    Parameters:
    
    node - The node.
    
    Returns:
    
    The depth of node.
  - getHeight
```
default int getHeight(N node)
```
    Returns the height of the tree under a node.
    It is the number of edges on the longest downward path between that node and a leaf.
    The height of a leaf node is 0.
    
    Parameters:
    
    node - The node. MUST NOT be null.
    
    Returns:
    
    The height of the tree under node.
  - getIndex
```
default int getIndex(N node)
```
    Returns the index of a child node in its parent's children.
    
    Parameters:
    
    node - The node.
    
    Returns:
    
    The index of node, or -1 if node is a root.
  - getQIndex
```
default int[] getQIndex(N node)
```
    Returns the qualified index of a node.
    It is the array of indices of the node and its ancestors, excluding the root node.
    A root node has an empty qindex.
    
    Parameters:
    
    node - The node.
    
    Returns:
    
    The qualified index of node
  - getFirstCommonAncestor
```
default N getFirstCommonAncestor(N node1,
                                 N node2)
```
    Returns the first common ancestor of 2 nodes.
    If nodes don't belong to the same tree or are null, returns null.
    
    Parameters:
    
    node1 - The first node.
    
    node2 - The second node.
    
    Returns:
    
    The first common ancestor of node1 and node2.
  - isOverOrEqual
```
default boolean isOverOrEqual(N node1,
                              N node2)
```
    Returns true when a first node is over or equal to a second node.
    
    Parameters:
    
    node1 - The first node.
    
    node2 - The second node.
    
    Returns:
    
    true when node1 is over or equal to node2.
  - isStrictlyOver
```
default boolean isStrictlyOver(N node1,
                               N node2)
```
    Returns true when a first node is strictly over a second node.
    
    Parameters:
    
    node1 - The first node.
    
    node2 - The second node.
    
    Returns:
    
    true when node1 is strictly over node2.
  - isOver
```
default boolean isOver(N node1,
                       N node2,
                       Strictness strictness)
```
    Returns true when a first node is loosely or strictly over a second node.
    
    Parameters:
    
    node1 - The first node.
    
    node2 - The second node.
    
    strictness - The strictness.
    
    Returns:
    
    true when a node1 is loosely or strictly over node2.
  - isUnderOrEqual
```
default boolean isUnderOrEqual(N node1,
                               N node2)
```
    Returns true when a first node is under or equal to a second node.
    
    Parameters:
    
    node1 - The first node.
    
    node2 - The second node.
    
    Returns:
    
    true when node1 is under or equal to node2.
  - isStrictlyUnder
```
default boolean isStrictlyUnder(N node1,
                                N node2)
```
    Returns true when a first node is strictly under a second node.
    
    Parameters:
    
    node1 - The first node.
    
    node2 - The second node.
    
    Returns:
    
    true when node1 strictly under node2.
  - isUnder
```
default boolean isUnder(N node1,
                        N node2,
                        Strictness strictness)
```
    Returns true when a first node is loosely or strictly under a second node.
    
    Parameters:
    
    node1 - The first node.
    
    node2 - The second node.
    
    strictness - The strictness.
    
    Returns:
    
    true when a node1 is loosely or strictly under node2.
  - areRelatedOrEqual
```
default boolean areRelatedOrEqual(N node1,
                                  N node2)
```
  - areStrictlyRelated
```
default boolean areStrictlyRelated(N node1,
                                   N node2)
```
  - areRelated
```
default boolean areRelated(N node1,
                           N node2,
                           Strictness strictness)
```
  - areUnrelated
```
default boolean areUnrelated(N node1,
                             N node2)
```
  - getRelativePosition
```
default NodeRelativePosition getRelativePosition(N node1,
                                                 N node2)
```
    Returns the relative position of 2 nodes.
    
    Parameters:
    
    node1 - The first node
    
    node2 - The second node.
    
    Returns:
    
    The position of node1 relatively to node2.
  - canSetParent
```
default boolean canSetParent(N node,
                             N candidateParent)
```
    Returns true when a node can be attached as a parent of another node.
    
    Parameters:
    
    node - The possible child.
    
    candidateParent - The possible parent.
    
    Returns:
    
    true when candidateParent can be set as parent of node.
  - getPath
```
default N[] getPath(N node)
```

Interface TreeAdapter<N>

Method Summary

Method Detail

getParent

getChildren

hasChildren

getRoot

isRoot

isLeaf

getDepth

getHeight

getIndex

getQIndex

getFirstCommonAncestor

isOverOrEqual

isStrictlyOver

isOver

isUnderOrEqual

isStrictlyUnder

isUnder

areRelatedOrEqual

areStrictlyRelated

areRelated

areUnrelated

getRelativePosition

canSetParent

getPath