org.eclipse.rdf4j.model.impl

## Class LinkedHashModel

- java.lang.Object
- - java.util.AbstractCollection<E>
  - - java.util.AbstractSet<Statement>
    - - org.eclipse.rdf4j.model.impl.AbstractModel
      - - org.eclipse.rdf4j.model.impl.LinkedHashModel

- All Implemented Interfaces:
    Serializable, Iterable<Statement>, Collection<Statement>, Set<Statement>, Model, NamespaceAware

      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 `Statement`s 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 * Models.synchronizedModel method.

  Author:
    James Leigh
  See Also:
    Serialized Form

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `LinkedHashModel.ModelStatement`

  - ### 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

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `add(Resource subj, IRI pred, Value obj, Resource... contexts)` Adds one or more statements to the model.
    `boolean` | `add(Statement statement)`
    `void` | `clear()`
    `boolean` | `contains(Object o)`
    `boolean` | `contains(Resource subj, IRI 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, IRI pred, Value obj, Resource... contexts)` Returns a filtered view of the statements with the specified subject, predicate, object and (optionally) context.
    `Optional<Namespace>` | `getNamespace(String prefix)` Gets the namespace that is associated with the specified prefix, if any.
    `Set<Namespace>` | `getNamespaces()` Gets the set that contains the assigned namespaces.
    `boolean` | `isEmpty()`
    `Iterator` | `iterator()`
    `boolean` | `remove(Resource subj, IRI pred, Value obj, Resource... contexts)` Removes statements with the specified subject, predicate, object and (optionally) context exist in this model.
    `Optional<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, IRI 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.eclipse.rdf4j.model.impl.AbstractModel

      `addAll, clear, closeIterator, containsAll, contexts, equals, hashCode, objects, predicates, remove, 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`

    - ### Methods inherited from interface org.eclipse.rdf4j.model.Model

      `add, contains, filter, getStatements, remove`

    - ### Methods inherited from interface java.util.Set

      `spliterator`

    - ### Methods inherited from interface java.util.Collection

      `parallelStream, removeIf, stream`

    - ### Methods inherited from interface java.lang.Iterable

      `forEach`

- - ### 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 Optional<Namespace> getNamespace(String prefix)

      Description copied from interface: `NamespaceAware`
      Gets the namespace that is associated with the specified prefix, if any. If multiple namespaces match the given prefix, the result may not be consistent over successive calls to this method.
      Parameters:
        `prefix` - A namespace prefix.
      Returns:
        The namespace name that is associated with the specified prefix, or `Optional.empty()` if there is no such namespace.

    - #### getNamespaces

          public Set<Namespace> getNamespaces()

      Description copied from interface: `NamespaceAware`
      Gets the set that contains the assigned namespaces.
      Returns:
        A `Set` containing the `Namespace` objects that are available.

    - #### setNamespace

          public Namespace setNamespace(String prefix,
                                        String name)

      Description copied from interface: `Model`
      Sets the prefix for a namespace. This will replace any existing namespace associated to the prefix.
      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. This will replace any existing namespace associated to the prefix.
      Parameters:
        `namespace` - A `Namespace` object to use in this Model.

    - #### removeNamespace

          public Optional<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 `Optional.empty()`

    - #### 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(Statement statement)

      Specified by:
        `add` in interface `Collection<Statement>`
      Specified by:
        `add` in interface `Set<Statement>`
      Overrides:
        `add` in class `AbstractModel`

    - #### add

          public boolean add(Resource subj,
                             IRI 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`

    - #### 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,
                                  IRI 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,
                                IRI 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,
                              IRI pred,
                              Value obj,
                              Resource... contexts)

      Description copied from interface: `Model`
      Returns a filtered 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.
      See Also:
        `Model.getStatements(Resource, IRI, Value, Resource...)`

    - #### removeTermIteration

          public void removeTermIteration(Iterator iterator,
                                          Resource subj,
                                          IRI 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

    - #### isEmpty

          public boolean isEmpty()

      Specified by:
        `isEmpty` in interface `Collection<Statement>`
      Specified by:
        `isEmpty` in interface `Set<Statement>`
      Overrides:
        `isEmpty` in class `AbstractModel`

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