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Difference between revisions of "XDI4j Tutorial 1"
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This interface represents a whole XDI graph. | This interface represents a whole XDI graph. | ||
− | XDI graphs consist of subjects and | + | XDI graphs consist of subjects, predicates, literals, references and inner graphs. |
− | Operations on the graph include creating | + | Operations on the graph include creating these graph components, finding and manipulating them |
=== Subject === | === Subject === |
Revision as of 18:52, 20 February 2008
Contents
Interfaces and classes
Graph
org.eclipse.higgins.xdi4j.Graph;
This interface represents a whole XDI graph. XDI graphs consist of subjects, predicates, literals, references and inner graphs. Operations on the graph include creating these graph components, finding and manipulating them
Subject
org.eclipse.higgins.xdi4j.Subject;
This interface represents a subject in an XDI graph. Methods include creating and finding predicates of the subject.
Predicate
org.eclipse.higgins.xdi4j.Predicate;
This interface represents a predicate in an XDI graph. Methods include creating and finding references, literals and inner graphs of the predicate.
Reference
org.eclipse.higgins.xdi4j.Reference;
This interface represents a reference in an XDI graph.
Literal
org.eclipse.higgins.xdi4j.Literal;
This interface represents a literal in an XDI graph.
Statement
org.eclipse.higgins.xdi4j.Statement;
This interface represents a statement in an XDI graph.
A statement consists of either:
- A subject (if the subject has no predicates).
- A subject and a predicate (if the predicate has no references or literals).
- A subject and a predicate and a reference.
- A subject and a predicate and a literal.
- A subject and a predicate and an inner graph.
A statement never has BOTH an reference and a literal.
GraphFactory
org.eclipse.higgins.xdi4j.GraphFactory;
Graph factories exist for all implementations of the Graph interface (e.g. Memory, XML, Hibernate). They can be used to create a new XDI document, or to load an existing one.
Example
This example app shows how to create a new XDI document and how to perform basic graph operations on it.
package org.eclipse.higgins.xdi4j.tutorial; import org.eclipse.higgins.xdi4j.Graph; import org.eclipse.higgins.xdi4j.GraphFactory; import org.eclipse.higgins.xdi4j.Predicate; import org.eclipse.higgins.xdi4j.Subject; import org.eclipse.higgins.xdi4j.impl.memory.MemoryGraphFactory; import org.eclipse.higgins.xdi4j.io.XDIWriter; import org.eclipse.higgins.xdi4j.io.XDIWriterRegistry; import org.eclipse.higgins.xdi4j.xri3.impl.XRI3Segment; /** * This example app shows how to create a new XDI * document and how to perform basic graph operations on it. * * @author msabadello at parityinc dot not * */ public class Tutorial1 { public static void main(String[] args) throws Exception { GraphFactory factory = MemoryGraphFactory.getInstance(); Graph graph = factory.openGraph(); // there are basically two ways of working with graphs // 1) work with subjects, predicates, references and literals Subject markus = graph.createSubject(new XRI3Segment("=markus")); Predicate name = markus.createPredicate(new XRI3Segment("+name")); Predicate friend = markus.createPredicate(new XRI3Segment("+friend")); name.createLiteral("Markus"); friend.createReference(new XRI3Segment("=drummond")); // 2) work with statements graph.createStatement(new XRI3Segment("=markus"), new XRI3Segment("+friend"), new XRI3Segment("=giovanni")); graph.createStatement(new XRI3Segment("=giovanni"), new XRI3Segment("+friend"), new XRI3Segment("=drummond")); // after our graph is filled, we can output it System.out.println(graph.toString()); graph.close(); } }