Difference between revisions of "XDI4j Tutorial 2"

Revision as of 08:01, 29 January 2010

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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

This example app shows how to output a graph in different serialization formats.

/*******************************************************************************
 * Copyright (c) 2008 Parity Communications, Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Markus Sabadello - Initial API and implementation
 *******************************************************************************/
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.
 * 
 * @author msabadello at parityinc dot not
 *
 */
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("=markus"), new XRI3Segment("+name"), "Markus");
		graph.createStatement(new XRI3Segment("=markus"), new XRI3Segment("+friend"), new XRI3Segment("=giovanni"));

		// 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

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;
		XDIReader reader;
		
		file = new File("test.graph");
		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();
	}
}