org.apache.jackrabbit.spi

Interface Path

All Superinterfaces:

Serializable

public interface Path
extends Serializable

The Path interface defines the SPI level representation of a JCR path. It consists of an ordered list of Path.Element objects and is immutable.

A Path.Element is either named or one of the following special elements:

• the current element (Notation: "."),
• the parent element (Notation: ".."),
• the root element (Notation: {}), which can only occur as the first element in a path, or
• an identifier element, which can only occur as the first element in a path.

A Path is defined to have the following characteristics:

Equality:
Two paths are equal if they consist of the same elements.

Length:
The length of a path is the number of its elements.

Depth:
The depth of a path is

• 0 for the root path,
• 0 for a path consisting of an identifier element only,
• 0 for the path consisting of the current element only,
• -1 for the path consisting of the parent element only,
• 1 for the path consisting of a single named element,
• depth(P) + depth(Q) for the path P/Q.

The depth of a normalized absolute path equals its length minus 1.

Absolute vs. Relative
A path can be absolute or relative:
A path is absolute if its first element is the root or an identifier element. A path is relative if it is not absolute.

• An absolute path is valid if its depth is greater or equals 0. A relative path is always valid.
• Two absolute paths are equivalent if "they refer to the same item in the hierarchy".
• Two relative paths P and Q are equivalent if for every absolute path R such that R/P and R/Q are valid, R/P and R/Q are equivalent.

Normalization:
A path P is normalized if P has minimal length amongst the set of all paths Q which are equivalent to P.
This means that '.' and '..' elements are resolved as much as possible. An absolute path it is normalized if it is not identifier-based and contains no current or parent elements. The normalization of a path is unique.

Equivalence:
Path P is equivalent to path Q (in the above sense) if the normalization of P is equal to the normalization of Q. This is an equivalence relation (i.e. reflexive, transitive, and symmetric).

Canonical Paths:
A path is canonical if its absolute and normalized.

Hierarchical Relationship:
The ancestor relationship is a strict partial order (i.e. irreflexive, transitive, and asymmetric). Path P is a direct ancestor of path Q if P is equivalent to Q/..
Path P is an ancestor of path Q if

• P is a direct ancestor of Q or
• P is a direct ancestor of some path S which is an ancestor of Q.

Path P is an descendant of path Q if

• Path P is a descendant of path Q if Q is an ancestor of P.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Path.Element Object representation of a single JCR path element.

Field Summary

Fields

Modifier and Type	Field and Description
static char	DELIMITER Delimiter used in order to concatenate the Path.Element objects upon getString().
static int	INDEX_DEFAULT Constant representing the default (initial) index value.
static int	INDEX_UNDEFINED Constant representing an undefined index value
static int	ROOT_DEPTH Constant defining the depth of the root path

Method Summary

Methods

Modifier and Type	Method and Description
Path	computeRelativePath(Path other) Computes the relative path from this absolute path to other.
boolean	denotesCurrent() Checks if the last path element is the current element (".").
boolean	denotesIdentifier() Test if this path consists of a single identifier element.
boolean	denotesName() Checks if the last path element is a named and optionally indexed element.
boolean	denotesParent() Checks if the last path element is the parent element ("..").
boolean	denotesRoot() Tests whether this is the root path, i.e.
Path	getAncestor(int degree) Normalizes this path and returns the ancestor path of the specified relative degree.
int	getAncestorCount() Returns the number of ancestors of this path.
Path	getCanonicalPath() Returns the canonical path representation of this path.
int	getDepth() Returns the depth of this path.
Path.Element[]	getElements() Returns the elements of this path.
Path	getFirstElements() Returns a path that consists of all but the last element of this path.
String	getIdentifier() Returns the identifier of a single identifier element.
int	getIndex() Returns the index of the last path element, or INDEX_UNDEFINED if the index is not defined or not applicable.
Path	getLastElement() Returns a path that consists of only the last element of this path.
int	getLength() Returns the length of this path, i.e.
Name	getName() Returns the name of the last path element, or null for an identifier.
Path.Element	getNameElement() Returns the name element (i.e.
int	getNormalizedIndex() Returns the normalized index of the last path element.
Path	getNormalizedPath() Returns the normalized path representation of this path.
String	getString() Returns the String representation of this Path as it is used by PathFactory.create(String).
boolean	isAbsolute() Tests whether this path is absolute, i.e.
boolean	isAncestorOf(Path other) Determines if this path is an ancestor of the specified path, based on their (absolute or relative) hierarchy level as returned by getDepth().
boolean	isCanonical() Tests whether this path is canonical, i.e.
boolean	isDescendantOf(Path other) Determines if this path is a descendant of the specified path, based on their (absolute or relative) hierarchy level as returned by getDepth().
boolean	isEquivalentTo(Path other) Determines if the the other path would be equal to this path if both of them are normalized.
boolean	isIdentifierBased() Test if this path represents an unresolved identifier-based path.
boolean	isNormalized() Tests whether this path is normalized, i.e.
Path	resolve(Path.Element element) Resolves the given path element against this path.
Path	resolve(Path relative) Resolves the given path against this path.
Path	subPath(int from, int to) Returns a new Path consisting of those Path.Element objects between the given from, inclusive, and the given to, exclusive.

Field Detail

INDEX_UNDEFINED

static final int INDEX_UNDEFINED

Constant representing an undefined index value

See Also:

Constant Field Values

INDEX_DEFAULT

static final int INDEX_DEFAULT

Constant representing the default (initial) index value.

See Also:

Constant Field Values

ROOT_DEPTH

static final int ROOT_DEPTH

Constant defining the depth of the root path

See Also:

Constant Field Values

DELIMITER

static final char DELIMITER

Delimiter used in order to concatenate the Path.Element objects upon getString().

See Also:

Constant Field Values

Method Detail

getName

Name getName()

Returns the name of the last path element, or null for an identifier. The names of the special root, current and parent elements are "", "." and ".." in the default namespace.

Returns:

name of the last path element, or null

getIndex

int getIndex()

Returns the index of the last path element, or INDEX_UNDEFINED if the index is not defined or not applicable. The index of an identifier or the special root, current or parent element is always undefined.

Returns:

index of the last path element, or INDEX_UNDEFINED

getNormalizedIndex

int getNormalizedIndex()

Returns the normalized index of the last path element. The normalized index of an element with an undefined index is INDEX_DEFAULT.

Returns:

normalized index of the last path element

getIdentifier

String getIdentifier()

Returns the identifier of a single identifier element. Returns null for non-identifier paths or identifier paths with other relative path elements.

Returns:

identifier, or null

denotesRoot

boolean denotesRoot()

Tests whether this is the root path, i.e. "/".

Returns:

true if this is the root path, false otherwise.

denotesIdentifier

boolean denotesIdentifier()

Test if this path consists of a single identifier element.

Returns:

true if this path is an identifier

denotesParent

boolean denotesParent()

Checks if the last path element is the parent element ("..").

Returns:

true if the last path element is the parent element, false otherwise

denotesCurrent

boolean denotesCurrent()

Checks if the last path element is the current element (".").

Returns:

true if the last path element is the current element, false otherwise

denotesName

boolean denotesName()

Checks if the last path element is a named and optionally indexed element.

Returns:

true if the last path element is a named element, false otherwise

isIdentifierBased

boolean isIdentifierBased()

Test if this path represents an unresolved identifier-based path.

Returns:

true if this path represents an unresolved identifier-based path.

isAbsolute

boolean isAbsolute()

Tests whether this path is absolute, i.e. whether it starts with "/" or is an identifier based path.

Returns:

true if this path is absolute; false otherwise.

isCanonical

boolean isCanonical()

Tests whether this path is canonical, i.e. whether it is absolute and does not contain redundant elements such as "." and "..".

Returns:

true if this path is canonical; false otherwise.

See Also:

isAbsolute()

isNormalized

boolean isNormalized()

Tests whether this path is normalized, i.e. whether it does not contain redundant elements such as "." and "..".

Note that a normalized path can still contain ".." elements if they are not redundant, e.g. "../../a/b/c" would be a normalized relative path, whereas "../a/../../a/b/c" wouldn't (although they're semantically equivalent).

Returns:

true if this path is normalized; false otherwise.

See Also:

getNormalizedPath()

getNormalizedPath

Path getNormalizedPath()
                       throws javax.jcr.RepositoryException

Returns the normalized path representation of this path.

If the path cannot be normalized (e.g. if an absolute path is normalized that would result in a 'negative' path) a RepositoryException is thrown.

Returns:

a normalized path representation of this path.

Throws:

javax.jcr.RepositoryException - if the path cannot be normalized.

See Also:

isNormalized()

getCanonicalPath

Path getCanonicalPath()
                      throws javax.jcr.RepositoryException

Returns the canonical path representation of this path.

If the path is relative or cannot be normalized a RepositoryException is thrown.

Returns:

a canonical path representation of this path.

Throws:

javax.jcr.RepositoryException - if this path can not be canonicalized (e.g. if it is relative).

resolve

Path resolve(Path.Element element)

Resolves the given path element against this path. If the given element is absolute (i.e. the root or an identifier element), then a path containing just that element is returned. Otherwise the returned path consists of this path followed by the given element.

Parameters:

element - path element

Returns:

resolved path

resolve

Path resolve(Path relative)

Resolves the given path against this path. If the given path is absolute, then it is returned as-is. Otherwise the path is resolved relative to this path and the resulting resolved path is returned.

Parameters:

relative - the path to be resolved

Returns:

resolved path

computeRelativePath

Path computeRelativePath(Path other)
                         throws javax.jcr.RepositoryException

Computes the relative path from this absolute path to other.

Parameters:

other - an absolute path.

Returns:

the relative path from this path to other path.

Throws:

javax.jcr.RepositoryException - if either this or other path is not absolute.

getAncestor

Path getAncestor(int degree)
                 throws IllegalArgumentException,
                        javax.jcr.PathNotFoundException,
                        javax.jcr.RepositoryException

Normalizes this path and returns the ancestor path of the specified relative degree.

An ancestor of relative degree x is the path that is x levels up along the path.

• degree = 0 returns this path.
• degree = 1 returns the parent of this path.
• degree = 2 returns the grandparent of this path.
• And so on to degree = n, where n is the depth of this path, which returns the root path.

If this path is relative the implementation may not be able to determine if the ancestor at degree exists. Such an implementation should properly build the ancestor (i.e. parent of .. is ../..) and leave if it the caller to throw PathNotFoundException.

Parameters:

degree - the relative degree of the requested ancestor.

Returns:

the normalized ancestor path of the specified degree.

Throws:

IllegalArgumentException - if degree is negative.

javax.jcr.PathNotFoundException - if the implementation is able to determine that there is no ancestor of the specified degree. In case of this being an absolute path, this would be the case if degree is greater that the depth of this path.

javax.jcr.RepositoryException - If the implementation is not able to determine the ancestor of the specified degree for some other reason.

getAncestorCount

int getAncestorCount()

Returns the number of ancestors of this path. This is the equivalent of getDepth() in case of a absolute path. For relative path the number of ancestors cannot be determined and -1 should be returned.

Returns:

the number of ancestors of this path or -1 if the number of ancestors cannot be determined.

See Also:

getDepth(), getLength(), isCanonical()

getLength

int getLength()

Returns the length of this path, i.e. the number of its elements. Note that the root element "/" counts as a separate element, e.g. the length of "/a/b/c" is 4 whereas the length of "a/b/c" is 3.

Also note that the special elements "." and ".." are not treated specially, e.g. both "/a/./.." and "/a/b/c" have a length of 4 but this value does not necessarily reflect the true hierarchy level as returned by getDepth().

Returns:

the length of this path

See Also:

getDepth(), getAncestorCount()

getDepth

int getDepth()

Returns the depth of this path. The depth reflects the absolute or relative hierarchy level this path is representing, depending on whether this path is an absolute or a relative path. The depth also takes '.' and '..' elements into account. The depth of the root path, an identifier and the current path must be 0.

Note that the returned value might be negative if this path is not canonical, e.g. the depth of "../../a" is -1.

Returns:

the depth this path

See Also:

getLength(), getAncestorCount()

isEquivalentTo

boolean isEquivalentTo(Path other)
                       throws IllegalArgumentException,
                              javax.jcr.RepositoryException

Determines if the the other path would be equal to this path if both of them are normalized.

Parameters:

other - Another path.

Returns:

true if the given other path is equivalent to this path.

Throws:

IllegalArgumentException - if the given path is null or if not both paths are either absolute or relative.

javax.jcr.RepositoryException - if any of the path cannot be normalized.

isAncestorOf

boolean isAncestorOf(Path other)
                     throws IllegalArgumentException,
                            javax.jcr.RepositoryException

Determines if this path is an ancestor of the specified path, based on their (absolute or relative) hierarchy level as returned by getDepth(). In case of undefined ancestor/descendant relationship that might occur with relative paths, the return value should be false.

Returns:

true if other is a descendant; otherwise false.

Throws:

IllegalArgumentException - if the given path is null or if not both paths are either absolute or relative.

javax.jcr.RepositoryException - if any of the path cannot be normalized.

See Also:

getDepth()

isDescendantOf

boolean isDescendantOf(Path other)
                       throws IllegalArgumentException,
                              javax.jcr.RepositoryException

Determines if this path is a descendant of the specified path, based on their (absolute or relative) hierarchy level as returned by getDepth(). In case of undefined ancestor/descendant relationship that might occur with relative paths, the return value should be false.

Returns:

true if other is an ancestor; otherwise false.

Throws:

IllegalArgumentException - if the given path is null or if not both paths are either absolute or relative.

javax.jcr.RepositoryException - if any of the path cannot be normalized.

See Also:

isAncestorOf(Path)

subPath

Path subPath(int from,
           int to)
             throws IllegalArgumentException

Returns a new Path consisting of those Path.Element objects between the given from, inclusive, and the given to, exclusive. An IllegalArgumentException is thrown if from is greater or equal than to or if any of both params is out of the possible range.

Parameters:

from - index of the element to start with and low endpoint (inclusive) within the list of elements to use for the sub-path.

to - index of the element outside of the range i.e. high endpoint (exclusive) within the list of elements to use for the sub-path.

Returns:

a new Path consisting of those Path.Element objects between the given from, inclusive, and the given to, exclusive.

Throws:

IllegalArgumentException - if from is greater or equal than to or if any of both params is out of the possible range.

getElements

Path.Element[] getElements()

Returns the elements of this path.

Returns:

the elements of this path.

getNameElement

Path.Element getNameElement()

Returns the name element (i.e. the last element) of this path.

Returns:

the name element of this path

getLastElement

Path getLastElement()

Returns a path that consists of only the last element of this path.

Returns:

last element of this path

See Also:

getFirstElements()

getFirstElements

Path getFirstElements()

Returns a path that consists of all but the last element of this path. Returns null if this path contains just a single element.

Returns:

first elements of this path, or null

See Also:

getLastElement()

getString

String getString()

Returns the String representation of this Path as it is used by PathFactory.create(String).

The String representation must consist of the String representation of its elements separated by DELIMITER.

Returns:

Returns the String representation of this Path.

See Also:

Path.Element.getString()