package org.neo4j.rdf.model;
import org.neo4j.graphdb.PropertyContainer;
import org.neo4j.rdf.store.RdfStore;
/**
* A hook for a statement which provides metadata editing and reading
* capabilities. A {@link StatementMetadata} implementation is typically
* provided by an {@link RdfStore} implementation and supplied to
* each {@link CompleteStatement} in f.ex
* {@link RdfStore#getStatements(WildcardStatement, boolean)}.
*/
public interface StatementMetadata
{
/**
* Returns wether or not a certain metadata exists.
* @param key the metadata key, typically a URI.
* @return <code>true</code> if the metadata exists, otherwise
* <code>false</code>.
*/
boolean has( String key );
/**
* Returns the metadata value (as a {@link Literal}) for a certain key.
* Throws a runtime exception if the specific metadata doesn't exist.
* @param key the metadata key, typically a URI.
* @return the metadata value for the given key, or throws exception
* if if doesn't exist.
*/
Literal get( String key );
/**
* Sets a metadata value for a certain key. Accepted values are those
* that a {@link PropertyContainer} accepts.
* @param key the metadata key, typically a URI.
* @param value the {@link Literal} value which will be associated with
* the key.
*/
void set( String key, Literal value );
/**
* Removes the metadata value for a certain key. Throws a runtime exception
* if the specific metadata doesn't exist.
* @param key the metadata key, typically a URI.
*/
void remove( String key );
/**
* @return all metadata keys for this statement.
*/
Iterable<String> getKeys();
}