Java aus xsd: JAXB

Etwas kleines, nicht neues, einfaches, aber extrem cooles:

Man hat ein Schema, z.B. das von XACML3,
http://docs.oasis-open.org/xacml/3.0/xacml-core-v3-schema-wd-17.xsd
und möchte davon mit Java eine Instanz abfüllen.

Nichts einfacher als das mit JAXB:

Man stelle das Schema in /src/main/xsd und lasse einen mvn install laufen, mit folgendem Plugin konfiguriert:

	<plugin>
	<groupId>org.codehaus.mojo</groupId>
	<artifactId>jaxb2-maven-plugin</artifactId>
	<version>1.5</version>
	<executions>
	<execution>
	<id>xjc</id>
	<goals>
	<goal>xjc</goal>
	</goals>
	</execution>
	</executions>
	</plugin>

view raw pom.xml hosted with ❤ by GitHub

	import java.io.StringReader;
	import java.io.StringWriter;
	import javax.xml.bind.JAXB;
	import oasis.names.tc.xacml._3_0.core.schema.wd_17.DecisionType;
	import oasis.names.tc.xacml._3_0.core.schema.wd_17.RequestType;
	import oasis.names.tc.xacml._3_0.core.schema.wd_17.ResponseType;
	import oasis.names.tc.xacml._3_0.core.schema.wd_17.ResultType;
	import oasis.names.tc.xacml._3_0.core.schema.wd_17.StatusType;
	public class XacmlMarshallUtil {
	public static Result extractResultFromXacmlResponseString(String xacmlResponseAsString) {
	StringReader reader = new StringReader(xacmlResponseAsString);
	ResponseType responseType = JAXB.unmarshal(reader, ResponseType.class);
	ResultType resultType = responseType.getResult().get(0);
	DecisionType decision = resultType.getDecision();
	StatusType status = resultType.getStatus();
	Result result = mapToOurResult(decision, status);
	return result;
	}

view raw unmarshall.java hosted with ❤ by GitHub

	package com.axa.ch.authorization.client.pep.facade;
	import static org.junit.Assert.assertEquals;
	import java.io.IOException;
	import org.junit.Test;
	import org.xml.sax.SAXException;
	import junit.framework.Assert;
	public class XacmlMarshallUtilTest {
	@Test
	public void testExtractResultFromXacmlResponseString() {
	Result result = XacmlMarshallUtil.extractResultFromXacmlResponseString(createResponse());
	assertEquals(Result.Decision.Deny, result.getDecision());
	}
	private String createResponse() {
	return "<?xml version=\"1.0\" encoding=\"UTF-8\"?> "
	+ "<Response xmlns=\"urn:oasis:names:tc:xacml:3.0:core:schema:wd-17\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xsi:schemaLocation=\"urn:oasis:names:tc:xacml:3.0:core:schema:wd-17 http://docs.oasis-open.org/xacml/3.0/xacml-core-v3-schema-wd-17.xsd\">"
	+ "<Result><Decision>Deny</Decision></Result></Response>";
	}
	}

view raw unmarshallTest.java hosted with ❤ by GitHub

Die generierten Klassen landen in target und werden von eclipse automatisch in den build-path genommen. Fertig. 

Die Klassen können dann ganz einfach benützt werden: hier wird z.B. ein XACML-String von JAXB geparst und in Java umgewandelt:

	import java.io.StringReader;
	import java.io.StringWriter;
	import javax.xml.bind.JAXB;
	import oasis.names.tc.xacml._3_0.core.schema.wd_17.DecisionType;
	import oasis.names.tc.xacml._3_0.core.schema.wd_17.RequestType;
	import oasis.names.tc.xacml._3_0.core.schema.wd_17.ResponseType;
	import oasis.names.tc.xacml._3_0.core.schema.wd_17.ResultType;
	import oasis.names.tc.xacml._3_0.core.schema.wd_17.StatusType;
	public class XacmlMarshallUtil {
	public static Result extractResultFromXacmlResponseString(String xacmlResponseAsString) {
	StringReader reader = new StringReader(xacmlResponseAsString);
	ResponseType responseType = JAXB.unmarshal(reader, ResponseType.class);
	ResultType resultType = responseType.getResult().get(0);
	DecisionType decision = resultType.getDecision();
	StatusType status = resultType.getStatus();
	Result result = mapToOurResult(decision, status);
	return result;
	}

view raw unmarshall.java hosted with ❤ by GitHub