source: java/main/src/main/java/com/framsticks/parsers/XmlLoader.java @ 100

package com.framsticks.parsers;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.LinkedList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import com.framsticks.params.Access;
import com.framsticks.params.Registry;
import com.framsticks.util.AutoBuilder;
import com.framsticks.util.FramsticksException;
import com.framsticks.util.lang.Strings;

public class XmlLoader {
        private static final Logger log = LogManager.getLogger(XmlLoader.class);

        protected Registry registry = new Registry();

        /**
         *
         */
        public XmlLoader() {
                registry.registerAndBuild(AutoInjector.class);
        }

        /**
         * @return the registry
         */
        public Registry getRegistry() {
                return registry;
        }

        boolean useLowerCase = false;

        /**
         * @param useLowerCase the useLowerCase to set
         */
        public void setUseLowerCase(boolean useLowerCase) {
                this.useLowerCase = useLowerCase;
        }

        public String mangleName(String name) {
                return useLowerCase ? name.toLowerCase() : name;
        }

        public String mangleAttribute(String name) {
                return useLowerCase ? name.toLowerCase() : Strings.uncapitalize(name);
        }

        public Object processElement(Element element, Class<?> enclosingClass) {
                final String name = mangleName(element.getNodeName());
                if (name.equals("import")) {
                        String className = element.getAttribute("class");
                        try {
                                registry.registerAndBuild(Class.forName(className));
                                return null;
                        } catch (ClassNotFoundException e) {
                                throw new FramsticksException().msg("failed to import class").arg("name", name).cause(e);
                        }
                }
                if (name.equals("include")) {
                        String fileName = element.getAttribute("file");
                        if (Strings.notEmpty(fileName)) {
                                try {
                                        return load(new FileInputStream(new File(fileName)), enclosingClass);
                                } catch (FileNotFoundException e) {
                                        throw new FramsticksException().msg("failed to include file").arg("file", fileName).cause(e);
                                }
                        }
                        String resourceName = element.getAttribute("resource");
                        if (Strings.notEmpty(resourceName)) {
                                Class<?> javaClass = enclosingClass;
                                String className = element.getAttribute("class");
                                if (Strings.notEmpty(className)) {
                                        try {
                                                javaClass = Class.forName(className);
                                        } catch (ClassNotFoundException e) {
                                                throw new FramsticksException().msg("failed to find class for resource loading").arg("class name", className).cause(e);
                                        }
                                }

                                return load(javaClass.getResourceAsStream(resourceName), enclosingClass);
                        }
                        throw new FramsticksException().msg("invalid <include/> node");
                }

                Access access = registry.createAccess(name);

                Object object = access.createAccessee();
                assert object != null;
                access.select(object);

                NamedNodeMap attributes = element.getAttributes();
                for (int i = 0; i < attributes.getLength(); ++i) {
                        Node attributeNode = attributes.item(i);
                        access.set(mangleAttribute(attributeNode.getNodeName()), attributeNode.getNodeValue());
                }

                NodeList children = element.getChildNodes();
                log.debug("found {} children in {}", children.getLength(), object);
                for (int i = 0; i < children.getLength(); ++i) {
                        Node childNode = children.item(i);
                        if (!(childNode instanceof Element)) {
                                continue;
                        }
                        Object childObject = processElement((Element) childNode, object.getClass());
                        if (childObject == null) {
                                continue;
                        }

                        List<Object> childrenObjects = new LinkedList<>();

                        if (childObject instanceof AutoBuilder) {
                                childrenObjects.addAll(((AutoBuilder) childObject).autoFinish());
                        } else {
                                childrenObjects.add(childObject);
                        }

                        for (Object child : childrenObjects) {
                                access.tryAutoAppend(child);
                        }
                }
                log.debug("loaded {}", object);

                return object;
        }

        protected Object load(InputStream stream, Class<?> enclosingClass) {
                try {
                        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
                        DocumentBuilder db = factory.newDocumentBuilder();

                        Document document = db.parse(stream);
                        document.getDocumentElement().normalize();
                        Element element = document.getDocumentElement();
                        assert element != null;

                        return processElement(element, enclosingClass);

                } catch (Exception e) {
                        throw new FramsticksException().msg("failed to load").cause(e);
                }
        }

        public <T> T load(Class<T> type, InputStream stream) {
                registry.registerAndBuild(type);

                Object object = load(stream, type);
                if (type.isAssignableFrom(object.getClass())) {
                        return type.cast(object);
                }
                throw new FramsticksException().msg("invalid type has been loaded");
        }
}