net.sf.saxon.om

Class AxisInfo

java.lang.Object

net.sf.saxon.om.AxisInfo

public final class AxisInfo
extends 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 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

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(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 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(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