xmlconfigurationprovider.java

在Struts2中的jar包xwork的源代码.版本为2.0.7

/*
 * Copyright (c) 2002-2006 by OpenSymphony
 * All rights reserved.
 */
package com.opensymphony.xwork2.config.providers;

import com.opensymphony.xwork2.util.ClassLoaderUtil;
import com.opensymphony.xwork2.util.FileManager;
import com.opensymphony.xwork2.util.TextUtils;
import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ObjectFactory;
import com.opensymphony.xwork2.XWorkException;
import com.opensymphony.xwork2.config.*;
import com.opensymphony.xwork2.config.impl.LocatableFactory;
import com.opensymphony.xwork2.config.entities.*;
import com.opensymphony.xwork2.inject.*;
import com.opensymphony.xwork2.util.DomHelper;
import com.opensymphony.xwork2.util.location.LocatableProperties;
import com.opensymphony.xwork2.util.location.Location;
import com.opensymphony.xwork2.util.location.LocationUtils;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Modifier;
import java.net.URL;
import java.util.*;


/**
 * Looks in the classpath for an XML file, "xwork.xml" by default,
 * and uses it for the XWork configuration.
 *
 * @author tmjee
 * @author Rainer Hermanns
 * @author Neo
 * @version $Revision: 1483 $
 */
public class XmlConfigurationProvider implements ConfigurationProvider {

    private static final Log LOG = LogFactory.getLog(XmlConfigurationProvider.class);

    private List<Document> documents;
    private Set<String> includedFileNames;
    private String configFileName;
    private ObjectFactory objectFactory;

    private Set<String> loadedFileUrls = new HashSet<String>();
    private boolean errorIfMissing;
    private Map<String, String> dtdMappings;
    private Configuration configuration;

    public XmlConfigurationProvider() {
        this("xwork.xml", true);
    }

    public XmlConfigurationProvider(String filename) {
        this(filename, true);
    }

    public XmlConfigurationProvider(String filename, boolean errorIfMissing) {
        this.configFileName = filename;
        this.errorIfMissing = errorIfMissing;

        Map<String, String> mappings = new HashMap<String, String>();
        mappings.put("-//OpenSymphony Group//XWork 2.0//EN", "xwork-2.0.dtd");
        mappings.put("-//OpenSymphony Group//XWork 1.1.1//EN", "xwork-1.1.1.dtd");
        mappings.put("-//OpenSymphony Group//XWork 1.1//EN", "xwork-1.1.dtd");
        mappings.put("-//OpenSymphony Group//XWork 1.0//EN", "xwork-1.0.dtd");
        setDtdMappings(mappings);
    }

    public void setDtdMappings(Map<String, String> mappings) {
        this.dtdMappings = Collections.unmodifiableMap(mappings);
    }

    @Inject
    public void setObjectFactory(ObjectFactory objectFactory) {
        this.objectFactory = objectFactory;
    }

    /**
     * Returns an unmodifiable map of DTD mappings
     */
    public Map<String, String> getDtdMappings() {
        return dtdMappings;
    }

    public void init(Configuration configuration) {
        this.configuration = configuration;
        this.includedFileNames = configuration.getLoadedFileNames();
        loadDocuments(configFileName);
    }

    public void destroy() {
    }

    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }

        if (!(o instanceof XmlConfigurationProvider)) {
            return false;
        }

        final XmlConfigurationProvider xmlConfigurationProvider = (XmlConfigurationProvider) o;

        if ((configFileName != null) ? (!configFileName.equals(xmlConfigurationProvider.configFileName)) : (xmlConfigurationProvider.configFileName != null)) {
            return false;
        }

        return true;
    }

    public int hashCode() {
        return ((configFileName != null) ? configFileName.hashCode() : 0);
    }

    private void loadDocuments(String configFileName) {
        try {
            loadedFileUrls.clear();
            documents = loadConfigurationFiles(configFileName, null);
        } catch (ConfigurationException e) {
            throw e;
        } catch (Exception e) {
            throw new ConfigurationException("Error loading configuration file " + configFileName, e);
        }
    }

    public void register(ContainerBuilder containerBuilder, LocatableProperties props) throws ConfigurationException {
        LOG.info("Parsing configuration file [" + configFileName + "]");
        Map<String, Node> loadedBeans = new HashMap<String, Node>();
        for (Document doc : documents) {
            Element rootElement = doc.getDocumentElement();
            NodeList children = rootElement.getChildNodes();
            int childSize = children.getLength();

            for (int i = 0; i < childSize; i++) {
                Node childNode = children.item(i);

                if (childNode instanceof Element) {
                    Element child = (Element) childNode;

                    final String nodeName = child.getNodeName();

                    if (nodeName.equals("bean")) {
                        String type = child.getAttribute("type");
                        String name = child.getAttribute("name");
                        String impl = child.getAttribute("class");
                        String onlyStatic = child.getAttribute("static");
                        String scopeStr = child.getAttribute("scope");
                        boolean optional = "true".equals(child.getAttribute("optional"));
                        Scope scope = Scope.SINGLETON;
                        if ("default".equals(scopeStr)) {
                            scope = Scope.DEFAULT;
                        } else if ("request".equals(scopeStr)) {
                            scope = Scope.REQUEST;
                        } else if ("session".equals(scopeStr)) {
                            scope = Scope.SESSION;
                        } else if ("singleton".equals(scopeStr)) {
                            scope = Scope.SINGLETON;
                        } else if ("thread".equals(scopeStr)) {
                            scope = Scope.THREAD;
                        }

                        if (!TextUtils.stringSet(name)) {
                            name = Container.DEFAULT_NAME;
                        }

                        try {
                            Class cimpl = ClassLoaderUtil.loadClass(impl, getClass());
                            Class ctype = cimpl;
                            if (TextUtils.stringSet(type)) {
                                ctype = ClassLoaderUtil.loadClass(type, getClass());
                            }
                            if ("true".equals(onlyStatic)) {
                                // Force loading of class to detect no class def found exceptions
                                cimpl.getDeclaredClasses();

                                containerBuilder.injectStatics(cimpl);
                            } else {
                                if (containerBuilder.contains(ctype, name)) {
                                    Location loc = LocationUtils.getLocation(loadedBeans.get(ctype.getName() + name));
                                    throw new ConfigurationException("Bean type " + ctype + " with the name " +
                                            name + " has already been loaded by " + loc, child);
                                }

                                // Force loading of class to detect no class def found exceptions
                                cimpl.getDeclaredConstructors();

                                if (LOG.isDebugEnabled()) {
                                    LOG.debug("Loaded type:" + type + " name:" + name + " impl:" + impl);
                                }
                                containerBuilder.factory(ctype, name, new LocatableFactory(name, ctype, cimpl, scope, childNode), scope);
                            }
                            loadedBeans.put(ctype.getName() + name, child);
                        } catch (Throwable ex) {
                            if (!optional) {
                                throw new ConfigurationException("Unable to load bean: type:" + type + " class:" + impl, ex, childNode);
                            } else {
                                LOG.debug("Unable to load optional class: " + ex);
                            }
                        }
                    } else if (nodeName.equals("constant")) {
                        String name = child.getAttribute("name");
                        String value = child.getAttribute("value");
                        props.setProperty(name, value, childNode);
                    }
                }
            }
        }
    }

    public void loadPackages() throws ConfigurationException {
        List<Element> reloads = new ArrayList<Element>();
        for (Document doc : documents) {
            Element rootElement = doc.getDocumentElement();
            NodeList children = rootElement.getChildNodes();
            int childSize = children.getLength();

            for (int i = 0; i < childSize; i++) {
                Node childNode = children.item(i);

                if (childNode instanceof Element) {
                    Element child = (Element) childNode;

                    final String nodeName = child.getNodeName();

                    if (nodeName.equals("package")) {
                        PackageConfig cfg = addPackage(child);
                        if (cfg.isNeedsRefresh()) {
                            reloads.add(child);
                        }
                    }
                }
            }
            loadExtraConfiguration(doc);
        }

        if (reloads.size() > 0) {
            reloadRequiredPackages(reloads);
        }

        for (Document doc : documents) {
            loadExtraConfiguration(doc);
        }

        documents.clear();
        configuration = null;
    }

    private void reloadRequiredPackages(List<Element> reloads) {
        if (reloads.size() > 0) {
            List<Element> result = new ArrayList<Element>();
            for (Element pkg : reloads) {
                PackageConfig cfg = addPackage(pkg);
                if (cfg.isNeedsRefresh()) {
                    result.add(pkg);
                }
            }
            if ((result.size() > 0) && (result.size() != reloads.size())) {
                reloadRequiredPackages(result);
                return;
            }

            // Print out error messages for all misconfigured inheritence packages
            if (result.size() > 0 ) {
                for (Element rp : result) {
                    String parent = rp.getAttribute("extends");
                    if ( parent != null) {
                        List parents = ConfigurationUtil.buildParentsFromString(configuration, parent);
                        if (parents != null && parents.size() <= 0) {
                            LOG.error("Unable to find parent packages " + parent);
                        }
                    }
                }
            }
        }
    }

    /**
     * Tells whether the ConfigurationProvider should reload its configuration. This method should only be called
     * if ConfigurationManager.isReloadingConfigs() is true.
     *
     * @return true if the file has been changed since the last time we read it
     */
    public boolean needsReload() {

        for (String url : loadedFileUrls) {
            if (FileManager.fileNeedsReloading(url)) {
                return true;
            }
        }
        return false;