XDI4j Tutorial 2

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This tutorial explains how to serialize and deserialize an XDI graph in any of the XDI serialization formats.

A typical application is to read an XDI graph from a file into memory, perform a few operations on it, and then store it again to file.

Serialization

Example Code:

package org.eclipse.higgins.xdi4j.tutorial;

import org.eclipse.higgins.xdi4j.Graph;
import org.eclipse.higgins.xdi4j.GraphFactory;
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 output
 * a graph in different serialization formats.
 */
public class Tutorial2 {

	public static void main(String[] args) throws Exception {

		GraphFactory factory = MemoryGraphFactory.getInstance();
		Graph graph = factory.openGraph();

		// let's create a simple graph

		graph.createStatement(new XRI3Segment("=alice"), new XRI3Segment("+name"), "Alice X.");
		graph.createStatement(new XRI3Segment("=alice"), new XRI3Segment("+friend"), new XRI3Segment("=bob"));

		// output the graph in X3 Simple and XDI/XML

		XDIWriter writer;

		writer = XDIWriterRegistry.forFormat("X3 Simple");
		writer.write(graph, System.out, null);

		writer = XDIWriterRegistry.forFormat("XDI/XML");
		writer.write(graph, System.out, null);

		graph.close();
	}
}

Deserialization

Example Code:

package org.eclipse.higgins.xdi4j.tutorial;

import java.io.File;
import java.io.FileInputStream;

import org.eclipse.higgins.xdi4j.Graph;
import org.eclipse.higgins.xdi4j.GraphFactory;
import org.eclipse.higgins.xdi4j.impl.memory.MemoryGraphFactory;
import org.eclipse.higgins.xdi4j.io.XDIReader;
import org.eclipse.higgins.xdi4j.io.XDIReaderRegistry;
import org.eclipse.higgins.xdi4j.io.XDIWriter;
import org.eclipse.higgins.xdi4j.io.XDIWriterRegistry;

/**
 * This example app shows how to read a graph in one format
 * and store it in another.
 */
public class Tutorial2A {

	public static void main(String[] args) throws Exception {

		GraphFactory factory = MemoryGraphFactory.getInstance();
		Graph graph = factory.openGraph();

		// read a graph from file

		File file = new File("test.graph");
		XDIReader reader = XDIReaderRegistry.getAuto();
		
		reader.read(graph, new FileInputStream(file), null);
		
		// output the graph in X3 Simple

		XDIWriter writer;

		writer = XDIWriterRegistry.forFormat("X3 Simple");
		writer.write(graph, System.out, null);

		graph.close();
	}
}