io.wcm.testing.mock.osgi.OsgiMetadataUtil.java Source code

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Here is the source code for io.wcm.testing.mock.osgi.OsgiMetadataUtil.java

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/*
 * #%L
 * wcm.io
 * %%
 * Copyright (C) 2014 wcm.io
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */
package io.wcm.testing.mock.osgi;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.xml.namespace.NamespaceContext;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.apache.commons.collections4.BidiMap;
import org.apache.commons.collections4.bidimap.DualHashBidiMap;
import org.apache.commons.lang3.StringUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

/**
 * Helper methods to parse OSGi metadata.
 */
final class OsgiMetadataUtil {

    private static final DocumentBuilderFactory DOCUMENT_BUILDER_FACTORY;
    static {
        DOCUMENT_BUILDER_FACTORY = DocumentBuilderFactory.newInstance();
        DOCUMENT_BUILDER_FACTORY.setNamespaceAware(true);
    }

    private static final XPathFactory XPATH_FACTORY = XPathFactory.newInstance();

    private static final BidiMap<String, String> NAMESPACES = new DualHashBidiMap<>();
    static {
        NAMESPACES.put("scr", "http://www.osgi.org/xmlns/scr/v1.1.0");
    }

    private OsgiMetadataUtil() {
        // static methods only
    }

    private static final NamespaceContext NAMESPACE_CONTEXT = new NamespaceContext() {
        @Override
        public String getNamespaceURI(String prefix) {
            return NAMESPACES.get(prefix);
        }

        @Override
        public String getPrefix(String namespaceURI) {
            return NAMESPACES.getKey(namespaceURI);
        }

        @Override
        public Iterator getPrefixes(String namespaceURI) {
            return NAMESPACES.keySet().iterator();
        }
    };

    /**
     * Try to read OSGI-metadata from /OSGI-INF and read all implemented interfaces and service properties
     * @param clazz OSGi service implementation class
     * @return Metadata document or null
     */
    public static Document geDocument(Class clazz) {
        String metadataPath = "/OSGI-INF/" + clazz.getName() + ".xml";
        InputStream metadataStream = clazz.getResourceAsStream(metadataPath);
        if (metadataStream == null) {
            return null;
        }
        try {
            DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
            return documentBuilder.parse(metadataStream);
        } catch (ParserConfigurationException | SAXException | IOException ex) {
            throw new RuntimeException("Unable to read classpath resource: " + metadataPath, ex);
        } finally {
            try {
                metadataStream.close();
            } catch (IOException ex) {
                // ignore
            }
        }
    }

    public static Set<String> getServiceInterfaces(Document document) {
        Set<String> serviceInterfaces = new HashSet<>();

        if (document != null) {
            try {
                XPath xpath = XPATH_FACTORY.newXPath();
                xpath.setNamespaceContext(NAMESPACE_CONTEXT);
                NodeList nodes = (NodeList) xpath.evaluate(
                        "/components/component[1]/service/provide[@interface!='']", document,
                        XPathConstants.NODESET);
                if (nodes != null) {
                    for (int i = 0; i < nodes.getLength(); i++) {
                        Node node = nodes.item(i);
                        String serviceInterface = node.getAttributes().getNamedItem("interface").getNodeValue();
                        if (StringUtils.isNotBlank(serviceInterface)) {
                            serviceInterfaces.add(serviceInterface);
                        }
                    }
                }
            } catch (XPathExpressionException ex) {
                throw new RuntimeException("Error evaluating XPath.", ex);
            }
        }

        return serviceInterfaces;
    }

    public static Map<String, Object> getProperties(Document document) {
        Map<String, Object> props = new HashMap<>();

        if (document != null) {
            try {
                XPath xpath = XPATH_FACTORY.newXPath();
                xpath.setNamespaceContext(NAMESPACE_CONTEXT);
                NodeList nodes = (NodeList) xpath.evaluate(
                        "/components/component[1]/property[@name!='' and @value!='']", document,
                        XPathConstants.NODESET);
                if (nodes != null) {
                    for (int i = 0; i < nodes.getLength(); i++) {
                        Node node = nodes.item(i);
                        String name = node.getAttributes().getNamedItem("name").getNodeValue();
                        String value = node.getAttributes().getNamedItem("value").getNodeValue();
                        String type = null;
                        Node typeAttribute = node.getAttributes().getNamedItem("type");
                        if (typeAttribute != null) {
                            type = typeAttribute.getNodeValue();
                        }
                        if (StringUtils.equals("Integer", type)) {
                            props.put(name, Integer.parseInt(value));
                        } else {
                            props.put(name, value);
                        }
                    }
                }
            } catch (XPathExpressionException ex) {
                throw new RuntimeException("Error evaluating XPath.", ex);
            }
        }

        return props;
    }

}