net.java.truevfs.kernel.spec

Class FsMountPoint

java.lang.Object

net.java.truevfs.kernel.spec.FsMountPoint

All Implemented Interfaces:

Serializable, Comparable<FsMountPoint>

@Immutable
public final class FsMountPoint
extends Object
implements Serializable, Comparable<FsMountPoint>

Addresses a file system mount point.

Specification

A mount point adds the following syntax constraints to a Uniform Resource Identifier:

1. The URI must be absolute, that is it must define a scheme component.
2. The URI must not define a query component.
3. The URI must not define a fragment component.
4. If the URI is opaque, its scheme specific part must end with the mount point separator "!/". The scheme specific part before the mount point separator is parsed according the syntax constraints for a FsNodePath and the following additional syntax constraints: The path component must be absolute. If its opaque, it's node name must not be empty. Finally, its set as the value of the path component property.
5. Otherwise, if the URI is hierarchical, its path component must be in normal form and end with a "/". The path component property of the mount point is set to null in this case.

Examples

Examples for valid mount point URIs:

uri property	scheme property	path URI	parent URI
"foo:/bar/"	"foo"	null	null
"foo:bar:/baz!/"	"foo"	"bar:/baz"	"bar:/"
"foo:bar:baz:/bang!/boom!/"	"foo"	"bar:baz:/bang!/boom"	"baz:/bang"

^* the property is null and hence its URI is not available.

Examples for invalid mount point URIs:

URI	Issue
/foo	not an absolute URI
foo:/bar	missing slash at end of hierarchical URI
foo:/bar/#baz	fragment component defined
foo:bar:/baz!/bang	missing mount point separator "!/" at end
foo:bar:baz:/bang!/!/	empty node name in path component after mount point "bar:baz:/bang!/"

Identities

For any mount point m, it's generally true that new FsMountPoint(m.getUri()).equals(m).

For any mount point m with an opaque URI, it's generally true that new FsMountPoint(m.getScheme(), m.getPath()).equals(m).

Serialization

This class supports serialization with both ObjectOutputStream and XMLEncoder.

Author:

Christian Schlichtherle

See Also:

FsNodePath, FsNodeName, FsScheme, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	SEPARATOR The separator which is used to split opaque path names into mount points and node names.

Constructor Summary

Constructors

Constructor and Description
FsMountPoint(FsScheme scheme, FsNodePath path) Constructs a new opaque mount point by composing its URI from the given scheme and path.
FsMountPoint(URI uri) Equivalent to new FsMountPoint(uri, FsUriModifier.NULL).
FsMountPoint(URI uri, FsUriModifier modifier) Constructs a new mount point by parsing the given URI.

Method Summary

Modifier and Type	Method and Description
int	compareTo(FsMountPoint that) Implements a natural ordering which is consistent with equals(Object).
static FsMountPoint	create(FsScheme scheme, FsNodePath path) Constructs a new mount point by composing its URI from the given scheme and path.
static FsMountPoint	create(URI uri) Equivalent to create(uri, FsUriModifier.NULL).
static FsMountPoint	create(URI uri, FsUriModifier modifier) Constructs a new mount point by parsing the given URI.
boolean	equals(Object that) Returns true iff the given object is a mount point and its URI equals the URI of this mount point.
FsMountPoint	getParent() Returns the parent component, that is the mount point of the parent file system, or null iff this mount point's URI doesn't name a parent mount point, that is if and only if it's hierarchical.
FsNodePath	getPath() Returns the path component or null iff this mount point's URI doesn't name a parent mount point, that is if and only if it's hierarchical.
FsScheme	getScheme() Returns the scheme component.
URI	getUri() Returns the URI for this mount point.
int	hashCode() Returns a hash code which is consistent with equals(Object).
FsNodePath	resolve(FsNodeName name) Resolves the given node name against this mount point.
URI	toHierarchicalUri() Returns a URI which is recursively transformed from the URI of this mount point so that it's absolute and hierarchical.
String	toString() Equivalent to calling URI.toString() on getUri().

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

SEPARATOR

public static final String SEPARATOR

The separator which is used to split opaque path names into mount points and node names. This is identical to the separator in the class JarURLConnection.

See Also:

Constant Field Values

Constructor Detail

FsMountPoint

public FsMountPoint(FsScheme scheme,
                    FsNodePath path)
             throws URISyntaxException

Constructs a new opaque mount point by composing its URI from the given scheme and path.

Parameters:

scheme - the non-null scheme.

path - the non-null path.

Throws:

URISyntaxException - if the composed mount point URI would not conform to the syntax constraints for mount points.

FsMountPoint

@ConstructorProperties(value="uri")
public FsMountPoint(URI uri)
                                                 throws URISyntaxException

Equivalent to new FsMountPoint(uri, FsUriModifier.NULL).

Throws:

URISyntaxException

FsMountPoint

public FsMountPoint(URI uri,
                    FsUriModifier modifier)
             throws URISyntaxException

Constructs a new mount point by parsing the given URI.

Parameters:

uri - the URI.

modifier - the URI modifier.

Throws:

URISyntaxException - if uri does not conform to the syntax constraints for mount points.

Method Detail

compareTo

public int compareTo(FsMountPoint that)

Implements a natural ordering which is consistent with equals(Object).

Specified by:

compareTo in interface Comparable<FsMountPoint>

create

public static FsMountPoint create(FsScheme scheme,
                                  FsNodePath path)

Constructs a new mount point by composing its URI from the given scheme and path. This static factory method calls new FsMountPoint(scheme, path) and wraps any thrown URISyntaxException in an IllegalArgumentException.

Parameters:

scheme - the scheme.

path - the path.

Returns:

A new mount point.

Throws:

IllegalArgumentException - if the composed mount point URI would not conform to the syntax constraints for mount points.

create

public static FsMountPoint create(URI uri)

Equivalent to create(uri, FsUriModifier.NULL).

create

public static FsMountPoint create(URI uri,
                                  FsUriModifier modifier)

Constructs a new mount point by parsing the given URI. This static factory method calls new FsMountPoint(uri, modifier) and wraps any thrown URISyntaxException in an IllegalArgumentException.

Parameters:

uri - the URI.

modifier - the URI modifier.

Returns:

A new mount point.

Throws:

IllegalArgumentException - if uri does not conform to the syntax constraints for mount points.

equals

public boolean equals(@CheckForNull
                      Object that)

Returns true iff the given object is a mount point and its URI equals the URI of this mount point. Note that this ignores the scheme and path.

Overrides:

equals in class Object

getParent

@Nullable
public FsMountPoint getParent()

Returns the parent component, that is the mount point of the parent file system, or null iff this mount point's URI doesn't name a parent mount point, that is if and only if it's hierarchical.

Returns:

The nullable parent component.

getPath

@Nullable
public FsNodePath getPath()

Returns the path component or null iff this mount point's URI doesn't name a parent mount point, that is if and only if it's hierarchical.

Returns:

The nullable path component.

getScheme

public FsScheme getScheme()

Returns the scheme component.

Returns:

The scheme component.

getUri

public URI getUri()

Returns the URI for this mount point.

Returns:

The URI for this mount point.

hashCode

public int hashCode()

Returns a hash code which is consistent with equals(Object).

Overrides:

hashCode in class Object

resolve

public FsNodePath resolve(FsNodeName name)

Resolves the given node name against this mount point.

Parameters:

name - a node name relative to this mount point.

Returns:

A new path with an absolute URI.

toHierarchicalUri

public URI toHierarchicalUri()

Returns a URI which is recursively transformed from the URI of this mount point so that it's absolute and hierarchical. If this mount point is already in absolute and hierarchical form, its URI gets returned.

For example, the mount point URIs zip:file:/archive!/ and tar:file:/archive!/ would both produce the hierarchical URI file:/archive.

Returns:

A URI which is recursively transformed from the URI of this mount point so that it's absolute and hierarchical.

toString

public String toString()

Equivalent to calling URI.toString() on getUri().

Overrides:

toString in class Object