com.theoryinpractise.halbuilder.xml.XmlRepresentationReader Maven / Gradle / Ivy

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HAL+XML serializer/deserializer extension to the HalBuilder Library
There is a newer version: 4.1.4
package com.theoryinpractise.halbuilder.xml;

import com.theoryinpractise.halbuilder.api.*;
import com.theoryinpractise.halbuilder.impl.representations.MutableRepresentation;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.Namespace;
import org.jdom.input.SAXBuilder;

import java.io.IOException;
import java.io.Reader;
import java.util.List;

import static com.theoryinpractise.halbuilder.impl.api.Support.*;

public class XmlRepresentationReader implements RepresentationReader {
    private RepresentationFactory representationFactory;

    public XmlRepresentationReader(RepresentationFactory representationFactory) {
        this.representationFactory = representationFactory;
    }

    public ReadableRepresentation read(Reader reader) {
        try {
            Document d = new SAXBuilder().build(reader);
            Element root = d.getRootElement();
            return readRepresentation(root).toImmutableResource();
        } catch (JDOMException e) {
            throw new RepresentationException(e);
        } catch (IOException e) {
            throw new RepresentationException(e);
        }
    }

    private MutableRepresentation readRepresentation(Element root) {
        String href = root.getAttributeValue("href");
        MutableRepresentation resource = new MutableRepresentation(representationFactory, href);

        readNamespaces(resource, root);
        readLinks(resource, root);
        readProperties(resource, root);
        readResources(resource, root);

        return resource;
    }

    private void readNamespaces(Representation resource, Element element) {
        List namespaces = element.getAdditionalNamespaces();
        for (Namespace ns : namespaces) {
            if (!"xsi".equals(ns.getPrefix())) {
                resource.withNamespace(ns.getPrefix(), ns.getURI());
            }
        }
    }

    private void readLinks(Representation resource, Element element) {

        List links = element.getChildren("link");
        for (Element link : links) {
            String rel = link.getAttributeValue(REL);
            String href = link.getAttributeValue(HREF);
            String name = link.getAttributeValue(NAME);
            String title = link.getAttributeValue(TITLE);
            String hreflang = link.getAttributeValue(HREFLANG);
            String profile = link.getAttributeValue(PROFILE);

            resource.withLink(rel, href, name, title, hreflang, profile);
        }

    }

    private void readProperties(Representation resource, Element element) {
        List properties = element.getChildren();
        for (Element property : properties) {
            if (!property.getName().matches("(link|resource)")) {
                if (property.getAttribute("nil", XSI_NAMESPACE) != null) {
                    resource.withProperty(property.getName(), null);
                } else {
                    resource.withProperty(property.getName(), property.getValue());
                }
            }
        }
    }

    private void readResources(Representation halResource, Element element) {
        List resources = element.getChildren("resource");
        for (Element resource : resources) {
            String rel = resource.getAttributeValue("rel");
            Representation subResource = readRepresentation(resource);
            halResource.withRepresentation(rel, subResource);
        }
    }
}