domfactory.java

用Java写的面相对象的数据库管理系统

            name = "openxml.printer.html.class";
            printerClass = HTMLPrinter.class;
        } else if (DTDDocument.class.isAssignableFrom( docClass )) {
            name = "openxml.printer.dtd.class";
            printerClass = DTDPrinter.class;
        } else {
            name = "openxml.printer.xml.class";
            printerClass = XMLPrinter.class;
        } 
        
        // Given the property name, read its value and if valid, attempt to
        // load the named printer class. Make sure this class is indeed a
        // printer. There is no way to check its ability to generate a document
        // of the requested type: the printer for HTML documents might be rigged
        // to only generate DTD documents. Such is life.
        name = getProperty( name );
        if (name != null) {
            try {
                printerClass = Class.forName( name );
                if (!Printer.class.isAssignableFrom( printerClass )) {
                    printerClass = XMLPrinter.class;
                    Log.error( "DOMFactory.createPrinter: Printer class [" + name 
                            + "] is not a supported printer -- defaulting to XMLPrinter" );
                } 
            } catch (ClassNotFoundException except) {
                Log.error( "DOMFactory.createPrinter: Could not locate printer class [" + name 
                        + "] -- defaulting to XMLPrinter" );
            } 
        } 
        
        // Printer class known, find the constructor which accepts a writer and
        // printing mode. This is the minimalist constructor for a printer and
        // is supported by all three printers. Using that constructor create a
        // new instance of the printer and return it.
        if (printerClass != null && printerClass != XMLPrinter.class) {
            try {
                cnst = printerClass.getConstructor( _printerSignature );
                return (Printer)cnst.newInstance( new Object[] {writer, new Integer( mode )} );
            } catch (Exception except) {
                Log.error( "DOMFactory.createPrinter: Could not create new instance of printer class [" 
                        + printerClass.getName() + "] -- defaulting to XMLPrinter" );
                Log.error( except );
            } 
        } 
        // Anything fails, or if specifically requested, return the default
        // XML printer.
        return new XMLPrinter( writer, mode );
    } 
    
    
    /**
     * Creates and returns a new XML printer.
     *
     * @param writer A writer for the document output
     * @param mode The printing mode
     * @return A new printer
     *
     * @deprecated
     *  This method has become obsolete in favor of the <a
     *  href="x3p/package-summary.html">X3P Publisher and Producer APIs</a>.
     *  This method is temporarily provided for backward compatibility but
     *  will not be included in release 1.1.
     */
    public static Printer createPrinter( Writer writer, int mode ) throws IOException {
        return createPrinter( writer, mode, DOCUMENT_XML );
    } 
    
    
    /**
     * Creates and returns a new XML/HTML/DTD printer. The printer type is
     * determined by the document class provided in <TT>docClass</TT>, which
     * dictates whether the printer is XML, HTML or DTD. If <TT>docClass</TT> is
     * null, the same rules that govern {@link #createDocument} apply here.
     *
     * @param output A stream for the document output
     * @param mode The printing mode
     * @param docClass The document type
     * @return A new printer
     *
     * @deprecated
     *  This method has become obsolete in favor of the <a
     *  href="x3p/package-summary.html">X3P Publisher and Producer APIs</a>.
     *  This method is temporarily provided for backward compatibility but
     *  will not be included in release 1.1.
     */
    public static Printer createPrinter( OutputStream stream, int mode, Class docClass ) throws IOException {
        return createPrinter( new XMLStreamWriter( stream ), mode, docClass );
    } 
    
    
    /**
     * Creates and returns a new XML printer.
     *
     * @param output A stream for the document output
     * @param mode The printing mode
     * @return A new printer
     *
     * @deprecated
     *  This method has become obsolete in favor of the <a
     *  href="x3p/package-summary.html">X3P Publisher and Producer APIs</a>.
     *  This method is temporarily provided for backward compatibility but
     *  will not be included in release 1.1.
     */
    public static Printer createPrinter( OutputStream stream, int mode ) throws IOException {
        return createPrinter( new XMLStreamWriter( stream ), mode, DOCUMENT_XML );
    } 
    
    
    /**
     * Returns the property from the OpenXML properties file.
     *
     * @param name The property name
     * @return Property value or null
     */
    public static String getProperty( String name ) {
        return getProperties().getProperty( name );
    } 
    
    
    /**
     * Returns the properties list from the OpenXML properties file. If this
     * property list is changed, changes will affect the behavior of the factory
     * and other OpenXML elements.
     *
     * @return The properties list
     */
    public static Properties getProperties() {
        String className;
        Class docClass;
        
        if (_xmlProps == null) {
            _xmlProps = new Properties();
            try {
                _xmlProps.load( DOMFactory.class.getResourceAsStream( RESOURCE_PROPS ) );
            } catch (Exception except) {
                Log.error( "DOMFactory.getProperties: Failed to load properties from resource [" + RESOURCE_PROPS 
                        + "]" );
                Log.error( except );
            } 
        } 
        return _xmlProps;
    } 
    
    
    /**
     * Returns the specified document class, or the properties file specified
     * class, or the default. If the specified document class is not valid, a
     * runtime exception is thrown. If the specified class is null, the name
     * is read from the properties file and used as the based class. If that
     * property is missing or not a valid class, the default document class
     * ({@link Document}) is used.
     *
     * @param docClass The specified document class, or null
     * @return A valid document class, extending {@link Document}
     */
    public static Class getDocClass( Class docClass ) {
        String prop;
        
        // If the specified document class is invalid, throw an exception,
        // as we do not want to assume default behavior.
        if (docClass != null) {
            if (docClass == DocumentType.class || docClass == DTDDocument.class) {
                return DTDDocument.class;
            } 
            if (!Document.class.isAssignableFrom( docClass )) {
                throw new IllegalArgumentException( "Requested document class is not a valid class." );
            } 
        } 
        // Read the property from the properties file and if not missing,
        // attempt to load the named class. If the named class does not extend
        // document, sadly it must be disposed of.
        prop = getProperty( "openxml.document.class" );
        if (prop != null) {
            try {
                docClass = Class.forName( prop );
                if (!Document.class.isAssignableFrom( docClass )) {
                    docClass = null;
                    Log.error( "DOMFactory.getDocClass: Document class [" + prop 
                            + "] is not a supported document class -- defaulting to Document" );
                } 
            } catch (ClassNotFoundException except) {
                Log.error( "DOMFactory.getDocClass: Could not locate document class [" + prop 
                        + "] -- defaulting to Document" );
            } 
        } 
        // The default is Document.
        if (docClass == null) {
            docClass = DOCUMENT_XML;
        } 
        return docClass;
    } 
    
    
    public static Source newSource() {
        getHolderFinder();
        return new SourceImpl();
    } 
    
    
    /**
     * Returns a singleton holder finder. This finder has default holder factories
     * registered for handling network, file, JAR and CLASSPATH document sources,
     * and mapping for built-in DTDs. Additional holder factories and Xcatalogs
     * may be specified in the properties file and are loaded and registered the
     * first time this method is called.
     *
     * @return An holder finder
     */
    public static HolderFinder getHolderFinder() {
        XCatalog catalog;
        String prop;
        StringTokenizer tokenizer;
        
        if (_finder == null) {
            _finder = HolderFinderImpl.getHolderFinder();
            catalog = XCatalogFactory.findCatalog( MAIN_CATALOG );
            if (catalog != null) {
                _finder.registerFactory( XCatalogFactory.asHolderFactory( catalog ) );
            } 
            
            prop = DOMFactory.getProperty( "openxml.holder.factories" );
            if (prop != null) {
                tokenizer = new StringTokenizer( prop, ";" );
                while (tokenizer.hasMoreTokens()) {
                    prop = tokenizer.nextToken();
                    try {
                        _finder.registerFactory( (HolderFactory)Class.forName( prop ).newInstance() );
                        Log.info( "DOMHolderFactory.<init>: Registered holder factory [" + prop + "]" );
                    } catch (Exception except) {
                        Log.error( "DOMHolderFactory.<init>: Failed to register holder factory [" + prop 
                                + "] -- class not found or could not be instantiated" );
                    } 
                } 
            } 
            
            prop = DOMFactory.getProperty( "openxml.holder.catalogs" );
            if (prop != null) {
                tokenizer = new StringTokenizer( prop, ";" );
                while (tokenizer.hasMoreTokens()) {
                    prop = tokenizer.nextToken();
                    try {
                        catalog = XCatalogFactory.findCatalog( prop );
                        
                        _finder.registerFactory( XCatalogFactory.asHolderFactory( catalog ) );
                        Log.info( "DOMHolderFactory.<init>: Registered XCatalog from [" + prop + "]" );
                    } catch (Exception except) {
                        Log.error( "DOMHolderFactory.<init>: Failed to register XCatalog from [" + prop 
                                + "] -- catalog not found or could not be loaded" );
                    } 
                } 
            } 
        } 
        return _finder;
    } 
    
    
    /**
     * XML document class. Can be used to request a new XML document, XML
     * parser or XML printer. Will produce a document of type {@link
     * Document}.
     */
    public final static Class DOCUMENT_XML = Document.class;
    
    
    /**
     * HTML document class. Can be used to request a new HTML document, HTML
     * parser or HTML printer. Will produce a document of type {@link
     * HTMLDocument}.
     */
    public final static Class DOCUMENT_HTML = HTMLDocumentImpl.class;
    
    
    /**
     * DTD document class. Can be used to request a new DTD document, DTD
     * parser or DTD printer. Will produce a document of type {@link
     * DTDDocument}.
     */
    public final static Class DOCUMENT_DTD = DocumentType.class;
    
    
    /**
     * Holds the properties for the factory. This object is created on-demand
     * when a property is first accessed.
     */
    private static Properties _xmlProps;
    
    
    /**
     * Holds a singleton holder finder.
     */
    private static HolderFinder _finder;
    
    
    /**
     * The signature for the constructor of a parser class (class that
     * implemented {@link Parser}). Accepts <TT>reader</TT> and
     * <TT>docClass</TT>.
     */
    private final static Class[] _parserSignature = new Class[] {Reader.class, String.class};
    
    
    /**
     * The signature for the constructor of a printer class (class that
     * implemented {@link Printer}). Accepts <TT>writer</TT> and <TT>mode</TT>.
     */
    private final static Class[] _printerSignature = new Class[] {Writer.class, int.class};
    
    
    /**
     * Identifies the properties file as a resource. The named resource will
     * be loaded with the DOMFactory class loader. If the resource exists in
     * a different package, the full package path must be included, preceded
     * with '/'.
     */
    private final static String RESOURCE_PROPS = "openxml.properties";
    
    
    private final static String MAIN_CATALOG = "res:/org/openxml/source/dtd-catalog/catalog.xml";
    
    
}