org.openrdf.model.impl

Class LinkedHashModel

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractSet<Statement>

org.openrdf.model.impl.AbstractModel

org.openrdf.model.impl.LinkedHashModel

All Implemented Interfaces:

Serializable, Iterable<Statement>, Collection<Statement>, Set<Statement>, Graph, Model

public class LinkedHashModel
extends AbstractModel

Hash table based implementation of the Model interface.

This implementation provides constant-time performance for filters using a single term, assuming the hash function disperses the elements properly among the buckets. Each term is indexed using a HashMap. When multiple terms are provided in a filter the index, of the term that reduces the possible Statements the most, is used and a sequential scan is used to filter additional terms.

Note that this implementation is not synchronized. If multiple threads access a model concurrently, and at least one of the threads modifies the model, it must be synchronized externally. This is typically accomplished by synchronizing on some object that naturally encapsulates the model. If no such object exists, the set should be "wrapped" using the Collections.synchronizedSet method. This is best done at creation time, to prevent accidental unsynchronized access to the LinkedHashModel instance (though the synchronization guarantee is only when accessing via the Set interface methods):

 Set s = Collections.synchronizedSet(new LinkedHashModel(...));
 

Since:

2.7.0

Author:

James Leigh

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
LinkedHashModel()
LinkedHashModel(Collection<? extends Statement> c)
LinkedHashModel(int size)
LinkedHashModel(Model model)
LinkedHashModel(Set<Namespace> namespaces)
LinkedHashModel(Set<Namespace> namespaces, Collection<? extends Statement> c)
LinkedHashModel(Set<Namespace> namespaces, int size)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(Resource subj, URI pred, Value obj, Resource... contexts) Adds one or more statements to the model.
void	clear()
boolean	contains(Object o)
boolean	contains(Resource subj, URI pred, Value obj, Resource... contexts) Determines if statements with the specified subject, predicate, object and (optionally) context exist in this model.
Model	filter(Resource subj, URI pred, Value obj, Resource... contexts) Returns a view of the statements with the specified subject, predicate, object and (optionally) context.
Namespace	getNamespace(String prefix) Gets the namespace that is associated with the specified prefix, if any.
Set<Namespace>	getNamespaces() Gets the map that contains the assigned namespaces.
Iterator	iterator()
boolean	remove(Object o)
boolean	remove(Resource subj, URI pred, Value obj, Resource... contexts) Removes statements with the specified subject, predicate, object and (optionally) context exist in this model.
Namespace	removeNamespace(String prefix) Removes a namespace declaration by removing the association between a prefix and a namespace name.
void	removeTermIteration(Iterator iterator, Resource subj, URI pred, Value obj, Resource... contexts) Called by aggregate sets when a term has been removed from a term iterator.
void	setNamespace(Namespace namespace) Sets the prefix for a namespace.
Namespace	setNamespace(String prefix, String name) Sets the prefix for a namespace.
int	size()

Methods inherited from class org.openrdf.model.impl.AbstractModel

add, addAll, clear, closeIterator, containsAll, contexts, equals, getValueFactory, hashCode, isEmpty, match, objectLiteral, objectResource, objects, objectString, objectURI, objectValue, predicates, removeAll, retainAll, subjects, toArray, toArray, unmodifiable

Methods inherited from class java.util.AbstractCollection

toString

Methods inherited from class java.lang.Object

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

Constructor Detail

LinkedHashModel

public LinkedHashModel()

LinkedHashModel

public LinkedHashModel(Model model)

LinkedHashModel

public LinkedHashModel(Collection<? extends Statement> c)

LinkedHashModel

public LinkedHashModel(int size)

LinkedHashModel

public LinkedHashModel(Set<Namespace> namespaces,
               Collection<? extends Statement> c)

LinkedHashModel

public LinkedHashModel(Set<Namespace> namespaces)

LinkedHashModel

public LinkedHashModel(Set<Namespace> namespaces,
               int size)

Method Detail

getNamespace

public Namespace getNamespace(String prefix)

Description copied from interface: Model

Gets the namespace that is associated with the specified prefix, if any.

Parameters:

prefix - A namespace prefix.

Returns:

The namespace name that is associated with the specified prefix, or null if there is no such namespace.

getNamespaces

public Set<Namespace> getNamespaces()

Description copied from interface: Model

Gets the map that contains the assigned namespaces.

Returns:

Map of prefix to namespace

setNamespace

public Namespace setNamespace(String prefix,
                     String name)

Description copied from interface: Model

Sets the prefix for a namespace.

Parameters:

prefix - The new prefix.

name - The namespace name that the prefix maps to.

Returns:

The Namespace object for the given namespace.

setNamespace

public void setNamespace(Namespace namespace)

Description copied from interface: Model

Sets the prefix for a namespace.

Parameters:

namespace - A Namespace object to use in this Model.

removeNamespace

public Namespace removeNamespace(String prefix)

Description copied from interface: Model

Removes a namespace declaration by removing the association between a prefix and a namespace name.

Parameters:

prefix - The namespace prefix of which the assocation with a namespace name is to be removed.

Returns:

the previous namespace bound to the prefix or null

size

public int size()

Specified by:

size in interface Collection<Statement>

Specified by:

size in interface Set<Statement>

Specified by:

size in class AbstractCollection<Statement>

add

public boolean add(Resource subj,
          URI pred,
          Value obj,
          Resource... contexts)

Description copied from interface: Model

Adds one or more statements to the model. This method creates a statement for each specified context and adds those to the model. If no contexts are specified, a single statement with no associated context is added. If this Model is a filtered Model then null (if context empty) values are permitted and will use the corresponding filtered values.

Parameters:

subj - The statement's subject.

pred - The statement's predicate.

obj - The statement's object.

contexts - The contexts to add statements to.

clear

public void clear()

Specified by:

clear in interface Collection<Statement>

Specified by:

clear in interface Set<Statement>

Overrides:

clear in class AbstractModel

remove

public boolean remove(Object o)

Specified by:

remove in interface Collection<Statement>

Specified by:

remove in interface Set<Statement>

Overrides:

remove in class AbstractModel

contains

public boolean contains(Object o)

Specified by:

contains in interface Collection<Statement>

Specified by:

contains in interface Set<Statement>

Overrides:

contains in class AbstractModel

iterator

public Iterator iterator()

Specified by:

iterator in interface Iterable<Statement>

Specified by:

iterator in interface Collection<Statement>

Specified by:

iterator in interface Set<Statement>

Specified by:

iterator in class AbstractCollection<Statement>

contains

public boolean contains(Resource subj,
               URI pred,
               Value obj,
               Resource... contexts)

Description copied from interface: Model

Determines if statements with the specified subject, predicate, object and (optionally) context exist in this model. The subject, predicate and object parameters can be null to indicate wildcards. The contexts parameter is a wildcard and accepts zero or more values. If no contexts are specified, statements will match disregarding their context. If one or more contexts are specified, statements with a context matching one of these will match. Note: to match statements without an associated context, specify the value null and explicitly cast it to type Resource.

Examples: model.contains(s1, null, null) is true if any statements in this model have subject s1,
model.contains(null, null, null, c1) is true if any statements in this model have context c1,
model.contains(null, null, null, (Resource)null) is true if any statements in this model have no associated context,
model.contains(null, null, null, c1, c2, c3) is true if any statements in this model have context c1, c2 or c3.

Parameters:

subj - The subject of the statements to match, null to match statements with any subject.

pred - The predicate of the statements to match, null to match statements with any predicate.

obj - The object of the statements to match, null to match statements with any object.

contexts - The contexts of the statements to match. If no contexts are specified, statements will match disregarding their context. If one or more contexts are specified, statements with a context matching one of these will match.

Returns:

true if statements match the specified pattern.

remove

public boolean remove(Resource subj,
             URI pred,
             Value obj,
             Resource... contexts)

Description copied from interface: Model

Removes statements with the specified subject, predicate, object and (optionally) context exist in this model. The subject, predicate and object parameters can be null to indicate wildcards. The contexts parameter is a wildcard and accepts zero or more values. If no contexts are specified, statements will be removed disregarding their context. If one or more contexts are specified, statements with a context matching one of these will be removed. Note: to remove statements without an associated context, specify the value null and explicitly cast it to type Resource.

Examples: model.remove(s1, null, null) removes any statements in this model have subject s1,
model.remove(null, null, null, c1) removes any statements in this model have context c1,
model.remove(null, null, null, (Resource)null) removes any statements in this model have no associated context,
model.remove(null, null, null, c1, c2, c3) removes any statements in this model have context c1, c2 or c3.

Parameters:

subj - The subject of the statements to remove, null to remove statements with any subject.

pred - The predicate of the statements to remove, null to remove statements with any predicate.

obj - The object of the statements to remove, null to remove statements with any object.

contexts - The contexts of the statements to remove. If no contexts are specified, statements will be removed disregarding their context. If one or more contexts are specified, statements with a context matching one of these will be removed.

Returns:

true if one or more statements have been removed.

filter

public Model filter(Resource subj,
           URI pred,
           Value obj,
           Resource... contexts)

Description copied from interface: Model

Returns a view of the statements with the specified subject, predicate, object and (optionally) context. The subject, predicate and object parameters can be null to indicate wildcards. The contexts parameter is a wildcard and accepts zero or more values. If no contexts are specified, statements will match disregarding their context. If one or more contexts are specified, statements with a context matching one of these will match. Note: to match statements without an associated context, specify the value null and explicitly cast it to type Resource.

The returned model is backed by this Model, so changes to this Model are reflected in the returned model, and vice-versa. If this Model is modified while an iteration over the returned model is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The model supports element removal, which removes the corresponding statement from this Model, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. The statements passed to the add and addAll operations must match the parameter pattern.

Examples: model.filter(s1, null, null) matches all statements that have subject s1,
model.filter(null, null, null, c1) matches all statements that have context c1,
model.filter(null, null, null, (Resource)null) matches all statements that have no associated context,
model.filter(null, null, null, c1, c2, c3) matches all statements that have context c1, c2 or c3.

Parameters:

subj - The subject of the statements to match, null to match statements with any subject.

pred - The predicate of the statements to match, null to match statements with any predicate.

obj - The object of the statements to match, null to match statements with any object.

contexts - The contexts of the statements to match. If no contexts are specified, statements will match disregarding their context. If one or more contexts are specified, statements with a context matching one of these will match.

Returns:

The statements that match the specified pattern.

removeTermIteration

public void removeTermIteration(Iterator iterator,
                       Resource subj,
                       URI pred,
                       Value obj,
                       Resource... contexts)

Description copied from class: AbstractModel

Called by aggregate sets when a term has been removed from a term iterator. Exactly one of the last four terms will be non-empty.

Specified by:

removeTermIteration in class AbstractModel

Parameters:

iterator - The iterator used to navigate the live set (never null)

subj - the subject term to be removed or null

pred - the predicate term to be removed or null

obj - the object term to be removed or null

contexts - an array of one context term to be removed or an empty array