XSLT

<?xml version="1.0" encoding="UTF-8"?>
        <project xmlns="http://maven.apache.org/POM/4.0.0"
                 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
            <modelVersion>4.0.0</modelVersion>
            <parent>
                <groupId>at.aydin.academy</groupId>
                <artifactId>31xslt-pair</artifactId>
                <version>1.0.0</version>
                <relativePath>../pom.xml</relativePath>
            </parent>
            <artifactId>xslt-modern</artifactId>
            <packaging>jar</packaging>
            <name>XSLT Modern</name>

            <dependencies>

<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter</artifactId>
    <scope>test</scope>
</dependency>

            </dependencies>
            <build>
                <plugins>
                    <plugin>
                        <groupId>org.apache.maven.plugins</groupId>
                        <artifactId>maven-compiler-plugin</artifactId>
                    </plugin>

                </plugins>
            </build>
        </project>

<catalog><book><title>Java</title></book></catalog>

<?xml version="1.0"?><xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"><xsl:output method="text"/><xsl:template match="/"><xsl:value-of select="catalog/book/title"/></xsl:template></xsl:stylesheet>

package at.aydin.lab.xslt.modern;

import javax.xml.XMLConstants;
import javax.xml.transform.*;
import javax.xml.transform.stream.*;
import java.io.*;

// Design Pattern: Flyweight
// Zweck: Thread-sichere Templates werden einmal kompiliert und für viele Transformationen wiederverwendet.
public final class SecureXsltTemplate {
    private final Templates templates;
    public SecureXsltTemplate(InputStream xsl) throws Exception {
        TransformerFactory f = TransformerFactory.newInstance();
        f.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
        f.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
        f.setAttribute(XMLConstants.ACCESS_EXTERNAL_STYLESHEET, "");
        templates = f.newTemplates(new StreamSource(xsl));
    }

    public String transform(InputStream xml) throws Exception {
        StringWriter out = new StringWriter();
        templates.newTransformer().transform(new StreamSource(xml), new StreamResult(out));
        return out.toString();
    }
}

package at.aydin.lab.xslt.modern;

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;

class SecureXsltTemplateTest {
    @Test
    void reusesCompiledTemplate() throws Exception {
        try (var s = getClass().getResourceAsStream("/title.xsl")) {
            var t = new SecureXsltTemplate(s);
            try (var x = getClass().getResourceAsStream("/catalog.xml")) {
                assertEquals("Java", t.transform(x));
            }
        }
    }
}