com.hp.hpl.jena.ontology
Class OntDocumentManager

java.lang.Object
  com.hp.hpl.jena.ontology.OntDocumentManager

public class OntDocumentManager
extends Object

Provides services for managing ontology documents, including loading imported documents, and locally caching documents from resolvable URL's to improve load performance. This class now delegates some of the responsibility for resolving URI's and caching models to FileManager. By default, OntDocumentManager will use a copy of the singleton global FileManager. Alternatively, a specific FileManager can be given to a document manager instance to use when resolving URI's and file paths. Note that the default behaviour is to hold a copy of the global file manager. In order to ensure that the document manager directly uses the global file manager (e.g. so that document manager sees updates to the location mappings held by the file manager), use the setFileManager(FileManager) method. For example:

OntDocumentManager dm = OntDocumentManager.getInstance();
 dm.setFileManager( FileManager.get() );

Note that in Jena 2.3, we have deprecated the capability of the document manager to store a table of known prefixes, and a table mapping document URI's to ontology language types. The intention is to remove both of these capabilities from Jena 2.4 onwards. If this change would be problematic, please send email to the Jena support list.

Version:

CVS $Id: OntDocumentManager.java,v 1.2 2009-10-06 13:04:34 ian_dickinson Exp $

Author:

Ian Dickinson, HP Labs (email)

Nested Class Summary

static class	OntDocumentManager.DefaultReadHook The default implementation of OntDocumentManager.ReadHook makes no changes.
static interface	OntDocumentManager.ReadFailureHandler Interface defining a handler call-back in the case that the OntDocumentManager fails in an attempt to read the contents of a URL into a model.
static interface	OntDocumentManager.ReadHook Interface denoting a handler class that can intervene in the process of reading a source document into a model.

Field Summary

static Property	ALT_URL Represents the alternative local copy of the public ontology; assumed to be resolvable, hence URL not URI
static String	ANCHOR The anchor char is added to the end of namespace prefix expansions
static Property	CACHE_MODELS Defines boolean policy choice of caching loaded models
static String	DEFAULT_METADATA_PATH The default path for searching for the metadata on locally cached ontologies
static Resource	DOC_MGR_POLICY rdf:type for document manager policy nodes
static Property	IGNORE_IMPORT Specifies the URI of an ontology that we do not want to import, even if processImports is true.
static Property	LANGUAGE Represents the ontology language used to encode the ontology
static String	NS Namespace for ontology metadata resources and properties
static Resource	ONTOLOGY_SPEC rdf:type for ontology specification nodes in meta-data file
static Property	PREFIX Represents the standard prefix for this namespace
static Property	PROCESS_IMPORTS Defines boolean policy choice of loading the imports closure
static Property	PUBLIC_URI Represents the public URI of an ontology; also used to derive the namespace
static Property	USE_DECLARED_NS_PREFIXES The policy property for including the pre-declared namespace prefixes in a model.

Constructor Summary

OntDocumentManager()
Initialise a document manager by searching the default path for ontology metadata about known ontologies cached locally.

OntDocumentManager(FileManager fileMgr, Model config)
Initialise a document manager with the given configuration model.

OntDocumentManager(FileManager fileMgr, String path)
Initialise a document manager by with the given FileManager, and then searching the given path for ontology metadata about known ontologies cached locally.

OntDocumentManager(Model config)
Initialise a document manager with the given configuration model.

OntDocumentManager(String path)
Initialise a document manager by searching the given path for ontology metadata about known ontologies cached locally.

Method Summary

void	addAltEntry(String docURI, String locationURL) Add an entry for an alternative copy of the document with the given document URI.
void	addIgnoreImport(String uri) Add the given URI to the set of URI's we ignore in imports statements
void	addModel(String docURI, Model model) Add an entry that model is the appropriate model to use for the given ontology document.
void	addModel(String docURI, Model model, boolean replace) Add an entry that model is the appropriate model to use for the given ontology document
void	clearCache() Remove all entries from the model cache
void	configure(Model config) Configure this document manager using the given configuration information, after first resetting the model back to all default values.
void	configure(Model config, boolean reset) Configure this document manager according to the configuration options supplied by the given configuration model.
String	doAltURLMapping(String uri) Answer the URL of the alternative copy of the ontology document with the given URI, if known, or the URI unchanged if no alternative is known.
void	forget(String docURI) Remove all managed entries for the given document.
boolean	getCacheModels() Answer true if the models loaded by this document manager from a given URI will be cached, so that they can be re-used in other compound ontology models.
FileManager	getFileManager() Answer the file manager instance being used by this document manager.
static OntDocumentManager	getInstance() OntDocumentManager is not a singleton, but a global default instance is available for applications where a single shared document manager is sufficient.
String	getLoadedPolicyURL() Answer the URL of the most recently loaded policy URL, or null if no document manager policy has yet been loaded since the metadata search path was last set.
String	getMetadataSearchPath() Answer the path used to search for the ontology metadata to load.
Model	getModel(String uri) Answer the cached model corresponding to the given document, if known.
OntModel	getOntology(String uri, OntModelSpec spec) Answer the ontology model that results from loading the document with the given URI.
boolean	getProcessImports() Answer the policy flag indicating whether the imports statements of loaded ontologies will be processed to build a union of s.
OntDocumentManager.ReadFailureHandler	getReadFailureHandler() Answer the handler object that handles failed document read attempts, or null if not defined.
OntDocumentManager.ReadHook	getReadHook() Answer the current ReadHook for this document manager instance
boolean	ignoringImport(String uri) Answer true if the given URI is one that will be ignored during imports
Iterator<String>	listDocuments() Answer an iterator over the ontology document URI's that this document manager knows to re-direct to other URL's.
Iterator<String>	listIgnoredImports() Answer an iterator over the set of URI's we're ignoring
void	loadImport(OntModel model, String uri) Add the given model from the given URI as an import to the given model.
void	loadImports(OntModel model) Inspect the statements in the graph expressed by the given model, and load into the model any imported documents.
void	removeIgnoreImport(String uri) Remove the given URI from the set of URI's we ignore in imports statements
void	reset() Reset all state in this document manager back to the default values it would have had when the object was created.
void	reset(boolean reload) Reset all state in this document manager back to the default values it would have had when the object was created.
void	setCacheModels(boolean cacheModels) Set the policy flag that indicates whether loaded models are cached by URI
void	setFileManager() Set the file manager used by this ODM instance to a copy of the global file manager (and, by extension, the global location mapper).
void	setFileManager(FileManager fileMgr) Set the file manager used by this ODM instance to a copy of the global file manager (and, by extension, the global location mapper).
void	setMetadataSearchPath(String path, boolean replace) Change the search path for loading ontology metadata to the given path.
void	setProcessImports(boolean processImports) Set the policy flag for processing imports of loaded ontologies.
void	setReadFailureHandler(OntDocumentManager.ReadFailureHandler rfHandler) Set the handler for read failures, overwriting any existing value.
OntDocumentManager.ReadHook	setReadHook(OntDocumentManager.ReadHook hook) Replace the existing ReadHook with the given value.
void	unloadImport(OntModel model, String uri) Remove from the given model the import denoted by the given URI.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_METADATA_PATH

public static final String DEFAULT_METADATA_PATH

The default path for searching for the metadata on locally cached ontologies

See Also:

Constant Field Values

NS

public static final String NS

Namespace for ontology metadata resources and properties

See Also:

Constant Field Values

ANCHOR

public static final String ANCHOR

The anchor char is added to the end of namespace prefix expansions

See Also:

Constant Field Values

ONTOLOGY_SPEC

public static final Resource ONTOLOGY_SPEC

rdf:type for ontology specification nodes in meta-data file

PUBLIC_URI

public static final Property PUBLIC_URI

Represents the public URI of an ontology; also used to derive the namespace

ALT_URL

public static final Property ALT_URL

Represents the alternative local copy of the public ontology; assumed to be resolvable, hence URL not URI

PREFIX

public static final Property PREFIX

Represents the standard prefix for this namespace

LANGUAGE

public static final Property LANGUAGE

Represents the ontology language used to encode the ontology

DOC_MGR_POLICY

public static final Resource DOC_MGR_POLICY

rdf:type for document manager policy nodes

CACHE_MODELS

public static final Property CACHE_MODELS

Defines boolean policy choice of caching loaded models

PROCESS_IMPORTS

public static final Property PROCESS_IMPORTS

Defines boolean policy choice of loading the imports closure

IGNORE_IMPORT

public static final Property IGNORE_IMPORT

Specifies the URI of an ontology that we do not want to import, even if processImports is true.

USE_DECLARED_NS_PREFIXES

public static final Property USE_DECLARED_NS_PREFIXES

The policy property for including the pre-declared namespace prefixes in a model.

Constructor Detail

OntDocumentManager

public OntDocumentManager()

Initialise a document manager by searching the default path for ontology metadata about known ontologies cached locally.

OntDocumentManager

public OntDocumentManager(String path)

Initialise a document manager by searching the given path for ontology metadata about known ontologies cached locally.

Parameters:

path - The search path to search for initial metadata, which will also replace the current search path for this document manager. Use null to prevent loading of any initial ontology metadata. The path is a series of URL's, separated by a semi-colon (;).

OntDocumentManager

public OntDocumentManager(FileManager fileMgr,
                          String path)

Initialise a document manager by with the given FileManager, and then searching the given path for ontology metadata about known ontologies cached locally.

Parameters:

path - The search path to search for initial metadata

See Also:

OntDocumentManager(String)

OntDocumentManager

public OntDocumentManager(Model config)

Initialise a document manager with the given configuration model. This model is used in place of any model that might be found by searching the meta-data search path. Uses the default file manager, i.e. a copy of the global file manager.

Parameters:

config - An RDF model containing configuration information for this document manager.

OntDocumentManager

public OntDocumentManager(FileManager fileMgr,
                          Model config)

Initialise a document manager with the given configuration model. This model is used in place of any model that might be found by searching the meta-data search path.

Parameters:

fileMgr - A file manager to use when locating source files for ontologies

config - An RDF model containing configuration information for this document manager.

Method Detail

getInstance

public static OntDocumentManager getInstance()

OntDocumentManager is not a singleton, but a global default instance is available for applications where a single shared document manager is sufficient.

Returns:

The default, global instance of a document manager

getFileManager

public FileManager getFileManager()

Answer the file manager instance being used by this document manager.

Returns:

This object's file manager

setReadHook

public OntDocumentManager.ReadHook setReadHook(OntDocumentManager.ReadHook hook)

Replace the existing ReadHook with the given value. The previous read hook is returned.

Parameters:

hook - The new read hook

Returns:

The old read hook

Throws:

IllegalArgumentException - if the new read hook is null

getReadHook

public OntDocumentManager.ReadHook getReadHook()

Answer the current ReadHook for this document manager instance

Returns:

The read hook

setFileManager

public void setFileManager()

Set the file manager used by this ODM instance to a copy of the global file manager (and, by extension, the global location mapper).

setFileManager

public void setFileManager(FileManager fileMgr)

Set the file manager used by this ODM instance to a copy of the global file manager (and, by extension, the global location mapper).

Parameters:

fileMgr - The new file manager

getMetadataSearchPath

public String getMetadataSearchPath()

Answer the path used to search for the ontology metadata to load. The format is a ';' separated list of URI's. The first URI on the path that is readable is taken to be the location of the local ontology metadata.

Returns:

The ontology metadata search path, as a string.

setMetadataSearchPath

public void setMetadataSearchPath(String path,
                                  boolean replace)

Change the search path for loading ontology metadata to the given path. If replace is true, any existing mappings are removed before the new path is searched. Otherwise, existing data will only be replaced if it is clobbered by keys loaded from the metadata loaded from the new path.

Parameters:

path - The new metadata search path (see getMetadataSearchPath() for format)

replace - If true, clear existing mappings first

setReadFailureHandler

public void setReadFailureHandler(OntDocumentManager.ReadFailureHandler rfHandler)

Set the handler for read failures, overwriting any existing value.

Parameters:

rfHandler - The new handler for failed document read attempts.

getReadFailureHandler

public OntDocumentManager.ReadFailureHandler getReadFailureHandler()

Answer the handler object that handles failed document read attempts, or null if not defined.

Returns:

The current read failure handler, or null

configure

public void configure(Model config)

Configure this document manager using the given configuration information, after first resetting the model back to all default values.

Parameters:

config - Document manager configuration as an RDF model

See Also:

configure( Model, boolean )

configure

public void configure(Model config,
                      boolean reset)

Configure this document manager according to the configuration options supplied by the given configuration model. If reset is true, the document manager is first reset back to all default values.

Parameters:

config - Document manager configuration as an RDF model

reset - If true, reset the document manager to default values, before attempting to configure the document manager using the given model.

See Also:

reset(boolean)

reset

public void reset(boolean reload)

Reset all state in this document manager back to the default values it would have had when the object was created. Optionally reload the profile metadata from the search path. Note that the metadata search path is not changed by this reset.

Parameters:

reload - If true, reload the configuration file from the search path.

reset

public void reset()

Reset all state in this document manager back to the default values it would have had when the object was created. This does not reload the configuration information from the search path. Note also that the metadata search path is one of the values that is reset back to its default value.

See Also:

reset( boolean )

listDocuments

public Iterator<String> listDocuments()

Answer an iterator over the ontology document URI's that this document manager knows to re-direct to other URL's. Note that being in this iteration does not mean that a document with the given name is in the set of cached models held by this document manager.

Returns:

An Iterator ranging over the public URI strings for the known document URI's.

doAltURLMapping

public String doAltURLMapping(String uri)

Answer the URL of the alternative copy of the ontology document with the given URI, if known, or the URI unchanged if no alternative is known.

Parameters:

uri - The ontology document to lookup

Returns:

The resolvable location of the alternative copy, if known, or uri otherwise

getModel

public Model getModel(String uri)

Answer the cached model corresponding to the given document, if known.

Parameters:

uri - The ontology document to lookup

Returns:

The model for the document, or null if the model is not known.

See Also:

getOntology(java.lang.String, com.hp.hpl.jena.ontology.OntModelSpec)

addAltEntry

public void addAltEntry(String docURI,
                        String locationURL)

Add an entry for an alternative copy of the document with the given document URI.

Parameters:

docURI - The public URI of the ontology document

locationURL - A locally resolvable URL where an alternative copy of the ontology document can be found

addModel

public void addModel(String docURI,
                     Model model)

Add an entry that model is the appropriate model to use for the given ontology document. Will not replace any existing model that is cached for this URI (see addModel(String, Model, boolean) for an alternative that can replace existing models).

Parameters:

docURI - The public URI of the ontology document

model - A model containing the triples from the document

addModel

public void addModel(String docURI,
                     Model model,
                     boolean replace)

Add an entry that model is the appropriate model to use for the given ontology document

Parameters:

docURI - The public URI of the ontology document

model - A model containing the triples from the document

replace - If true, replace any existing entry with this one.

forget

public void forget(String docURI)

Remove all managed entries for the given document. Note does not side-effect the prefixes table: this will have to be done separately.

Parameters:

docURI - The public URI for an ontology document

getOntology

public OntModel getOntology(String uri,
                            OntModelSpec spec)

Answer the ontology model that results from loading the document with the given URI. This may be a cached model, if this document manager's policy is to cache loaded models. If not, or if no model is cached, the document will be read into a suitable model. The model will contain the imports closure of the ontology, if that is the current policy of this document manager.

Parameters:

uri - Identifies the model to load.

spec - Specifies the structure of the ontology model to create

Returns:

An ontology model containing the statements from the ontology document.

See Also:

getModel(java.lang.String)

getProcessImports

public boolean getProcessImports()

Answer the policy flag indicating whether the imports statements of loaded ontologies will be processed to build a union of s.

Returns:

True if imported models will be included in a loaded model

getCacheModels

public boolean getCacheModels()

Answer true if the models loaded by this document manager from a given URI will be cached, so that they can be re-used in other compound ontology models.

Returns:

If true, a cache is maintained of loaded models from their URI's.

setProcessImports

public void setProcessImports(boolean processImports)

Set the policy flag for processing imports of loaded ontologies.

Parameters:

processImports - If true, load imported ontologies during load

See Also:

getProcessImports()

setCacheModels

public void setCacheModels(boolean cacheModels)

Set the policy flag that indicates whether loaded models are cached by URI

Parameters:

cacheModels - If true, models will be cached by URI

See Also:

getCacheModels()

addIgnoreImport

public void addIgnoreImport(String uri)

Add the given URI to the set of URI's we ignore in imports statements

Parameters:

uri - A URI to ignore when importing

removeIgnoreImport

public void removeIgnoreImport(String uri)

Remove the given URI from the set of URI's we ignore in imports statements

Parameters:

uri - A URI to ignore no longer when importing

listIgnoredImports

public Iterator<String> listIgnoredImports()

Answer an iterator over the set of URI's we're ignoring

Returns:

An iterator over ignored imports

ignoringImport

public boolean ignoringImport(String uri)

Answer true if the given URI is one that will be ignored during imports

Parameters:

uri - A URI to test

Returns:

True if uri will be ignored as an import

clearCache

public void clearCache()

Remove all entries from the model cache

loadImports

public void loadImports(OntModel model)

Inspect the statements in the graph expressed by the given model, and load into the model any imported documents. Imports statements are recognised according to the model's language profile. An occurs check allows cycles of importing safely. This method will do nothing if the policy for this manager is not to process imports. If the cache policy for this doc manager allows, models will be cached by URI and re-used where possible.

Parameters:

model - An ontology model whose imports are to be loaded.

loadImport

public void loadImport(OntModel model,
                       String uri)

Add the given model from the given URI as an import to the given model. Any models imported by the given URI will also be imported.

Parameters:

model - A model to import into

uri - The URI of a document to import

unloadImport

public void unloadImport(OntModel model,
                         String uri)

Remove from the given model the import denoted by the given URI.

Parameters:

model - A model

uri - The URI of a document to no longer import

getLoadedPolicyURL

public String getLoadedPolicyURL()

Answer the URL of the most recently loaded policy URL, or null if no document manager policy has yet been loaded since the metadata search path was last set.

Returns:

The most recently loaded policy URL or null.