AxisInfo

java.lang.Object
- net.sf.saxon.om.AxisInfo

```
public final class AxisInfo
extends java.lang.Object
```
An axis, that is a direction of navigation in the document structure.

Field Summary

Fields
Modifier and Type	Field and Description
`static byte`	`ANCESTOR` Constant representing the ancestor axis
`static byte`	`ANCESTOR_OR_SELF` Constant representing the ancestor-or-self axis
`static byte`	`ATTRIBUTE` Constant representing the attribute axis
`static java.lang.String[]`	`axisName` Table giving the name of each axis as used in XPath, for example "ancestor-or-self"
`static byte`	`CHILD` Constant representing the child axis
`static byte`	`DESCENDANT` Constant representing the descendant axis
`static byte`	`DESCENDANT_OR_SELF` Constant representing the descendant-or-self axis
`static byte[]`	`excludeSelfAxis` Give the corresponding axis if the self node is excluded.
`static byte`	`FOLLOWING` Constant representing the following axis
`static byte`	`FOLLOWING_SIBLING` Constant representing the following-sibling axis
`static byte[]`	`inverseAxis` For each axis, determine the inverse axis, in the sense that if A is on axis X starting at B, the B is on the axis inverseAxis[X] starting at A.
`static boolean[]`	`isForwards` Table indicating for each axis whether it is in forwards document order
`static boolean[]`	`isPeerAxis` Table indicating for each axis whether it is a peer axis.
`static boolean[]`	`isSubtreeAxis` Table indicating for each axis whether it is contained within the subtree rooted at the origin node.
`static byte`	`NAMESPACE` Constant representing the namespace axis
`static byte`	`PARENT` Constant representing the parent axis
`static byte`	`PRECEDING` Constant representing the preceding axis
`static byte`	`PRECEDING_OR_ANCESTOR` Constant representing the preceding-or-ancestor axis.
`static byte`	`PRECEDING_SIBLING` Constant representing the preceding-sibling axis
`static short[]`	`principalNodeType` Table indicating the principal node type of each axis
`static UType[]`	`principalNodeUType`
`static byte`	`SELF` Constant representing the self axis

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static boolean`	`containsNodeKind(int axis, int nodeKind)` Determine whether a given kind of node can be found on a given axis.
`static byte`	`getAxisNumber(java.lang.String name)` Resolve an axis name into a symbolic constant representing the axis
`static UType`	`getTargetUType(UType origin, byte axis)` Given a context item type and an axis, determine the kinds of nodes that can be returned
`static boolean`	`isAlwaysEmpty(int axis, int nodeKind)` Ask whether a given axis can contain any nodes when starting at the specified node kind.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - ANCESTOR
```
public static final byte ANCESTOR
```
    Constant representing the ancestor axis
    
    See Also:
    
    Constant Field Values
  - ANCESTOR_OR_SELF
```
public static final byte ANCESTOR_OR_SELF
```
    Constant representing the ancestor-or-self axis
    
    See Also:
    
    Constant Field Values
  - ATTRIBUTE
```
public static final byte ATTRIBUTE
```
    Constant representing the attribute axis
    
    See Also:
    
    Constant Field Values
  - CHILD
```
public static final byte CHILD
```
    Constant representing the child axis
    
    See Also:
    
    Constant Field Values
  - DESCENDANT
```
public static final byte DESCENDANT
```
    Constant representing the descendant axis
    
    See Also:
    
    Constant Field Values
  - DESCENDANT_OR_SELF
```
public static final byte DESCENDANT_OR_SELF
```
    Constant representing the descendant-or-self axis
    
    See Also:
    
    Constant Field Values
  - FOLLOWING
```
public static final byte FOLLOWING
```
    Constant representing the following axis
    
    See Also:
    
    Constant Field Values
  - FOLLOWING_SIBLING
```
public static final byte FOLLOWING_SIBLING
```
    Constant representing the following-sibling axis
    
    See Also:
    
    Constant Field Values
  - NAMESPACE
```
public static final byte NAMESPACE
```
    Constant representing the namespace axis
    
    See Also:
    
    Constant Field Values
  - PARENT
```
public static final byte PARENT
```
    Constant representing the parent axis
    
    See Also:
    
    Constant Field Values
  - PRECEDING
```
public static final byte PRECEDING
```
    Constant representing the preceding axis
    
    See Also:
    
    Constant Field Values
  - PRECEDING_SIBLING
```
public static final byte PRECEDING_SIBLING
```
    Constant representing the preceding-sibling axis
    
    See Also:
    
    Constant Field Values
  - SELF
```
public static final byte SELF
```
    Constant representing the self axis
    
    See Also:
    
    Constant Field Values
  - PRECEDING_OR_ANCESTOR
```
public static final byte PRECEDING_OR_ANCESTOR
```
    Constant representing the preceding-or-ancestor axis. This axis is used internally by the xsl:number implementation, it returns the union of the preceding axis and the ancestor axis.
    
    See Also:
    
    Constant Field Values
  - principalNodeType
```
public static final short[] principalNodeType
```
    Table indicating the principal node type of each axis
  - principalNodeUType
```
public static final UType[] principalNodeUType
```
  - isForwards
```
public static final boolean[] isForwards
```
    Table indicating for each axis whether it is in forwards document order
  - isPeerAxis
```
public static final boolean[] isPeerAxis
```
    Table indicating for each axis whether it is a peer axis. An axis is a peer axis if no node on the axis is an ancestor of another node on the axis.
  - isSubtreeAxis
```
public static final boolean[] isSubtreeAxis
```
    Table indicating for each axis whether it is contained within the subtree rooted at the origin node.
  - axisName
```
public static final java.lang.String[] axisName
```
    Table giving the name of each axis as used in XPath, for example "ancestor-or-self"
  - inverseAxis
```
public static byte[] inverseAxis
```
    For each axis, determine the inverse axis, in the sense that if A is on axis X starting at B, the B is on the axis inverseAxis[X] starting at A. This doesn't quite work for the PARENT axis, which has no simple inverse: this table gives the inverse as CHILD
  - excludeSelfAxis
```
public static byte[] excludeSelfAxis
```
    Give the corresponding axis if the self node is excluded. (Doesn't really work for the self axis itself).
- Method Detail
  - getAxisNumber
```
public static byte getAxisNumber(java.lang.String name)
                          throws XPathException
```
    Resolve an axis name into a symbolic constant representing the axis
    
    Parameters:
    
    name - the name of the axis
    
    Returns:
    
    integer value representing the named axis
    
    Throws:
    
    XPathException - if the axis name is not one of the defined axes
  - isAlwaysEmpty
```
public static boolean isAlwaysEmpty(int axis,
                                    int nodeKind)
```
    Ask whether a given axis can contain any nodes when starting at the specified node kind. For example, the attribute axis when starting at an attribute node will always be empty
    
    Parameters:
    
    axis - the axis, for example ATTRIBUTE
    
    nodeKind - the node kind of the origin node, for example Type.ATTRIBUTE
    
    Returns:
    
    true if no nodes will ever appear on the specified axis when starting at the specified node kind.
  - containsNodeKind
```
public static boolean containsNodeKind(int axis,
                                       int nodeKind)
```
    Determine whether a given kind of node can be found on a given axis. For example, the attribute axis will never contain any element nodes.
    
    Parameters:
    
    axis - the axis, for example ATTRIBUTE
    
    nodeKind - the node kind of the origin node, for example Type.ELEMENT
    
    Returns:
    
    true if the given kind of node can appear on the specified axis
  - getTargetUType
```
public static UType getTargetUType(UType origin,
                                   byte axis)
```
    Given a context item type and an axis, determine the kinds of nodes that can be returned
    
    Parameters:
    
    origin - the context item type, as a UType representing one or more node kinds
    
    axis - identifies the axis
    
    Returns:
    
    the set of possible node kinds in the result of the axis expression, as a UType

Class AxisInfo

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ANCESTOR

ANCESTOR_OR_SELF

ATTRIBUTE

CHILD

DESCENDANT

DESCENDANT_OR_SELF

FOLLOWING

FOLLOWING_SIBLING

NAMESPACE

PARENT

PRECEDING

PRECEDING_SIBLING

SELF

PRECEDING_OR_ANCESTOR

principalNodeType

principalNodeUType

isForwards

isPeerAxis

isSubtreeAxis

axisName

inverseAxis

excludeSelfAxis

Method Detail

getAxisNumber

isAlwaysEmpty

containsNodeKind

getTargetUType