xmlpackagereader.java

jboss规则引擎

     * @see org.xml.sax.ContentHandler
     */
    public void endElement(final String uri,
                           final String localName,
                           final String qname) throws SAXException {
        final Handler handler = getHandler( localName );

        if ( (handler != null) && (!this.parents.isEmpty() && this.parents.getLast() instanceof RuleDescr) ) {
            this.inHandledRuleSubElement = false;
        }

        if ( handler == null ) {
            if ( this.configurationStack.size() >= 1 ) {
                endConfiguration();
            }
            return;
        }

        this.current = getParent( handler.generateNodeFor() );

        final Object node = handler.end( uri,
                                   localName );

        // next
        if ( node != null && !this.lastWasEndElement ) {
            this.peer = node;
        }
        // up or no children
        else if ( this.lastWasEndElement || (this.parents.getLast()).getClass().isInstance( this.current ) ) {
            this.peer = this.parents.removeLast();
        }

        this.lastWasEndElement = true;
    }

    private void validate(final String uri,
                          final String localName,
                          final Handler handler) throws SAXParseException {
        boolean validParent = false;
        boolean validPeer = false;
        boolean invalidNesting = false;

        final Set validParents = handler.getValidParents();
        final Set validPeers = handler.getValidPeers();
        boolean allowNesting = handler.allowNesting();

        // get parent
        Object parent;
        if ( this.parents.size() != 0 ) {
            parent = this.parents.getLast();
        } else {
            parent = null;
        }

        // check valid parents
        // null parent means localname is rule-set
        // dont process if elements are the same
        // instead check for allowed nesting
        final Class nodeClass = getHandler( localName ).generateNodeFor();
        if ( !nodeClass.isInstance( parent ) ) {
            Object allowedParent;
            final Iterator it = validParents.iterator();
            while ( !validParent && it.hasNext() ) {
                allowedParent = it.next();
                if ( parent == null && allowedParent == null ) {
                    validParent = true;
                } else if ( allowedParent != null && ((Class) allowedParent).isInstance( parent ) ) {
                    validParent = true;
                }
            }
            if ( !validParent ) {
                throw new SAXParseException( "<" + localName + "> has an invalid parent element [" + parent + "]",
                                             getLocator() );
            }
        }

        // check valid peers
        // null peer means localname is rule-set
        final Object peer = this.peer;

        Object allowedPeer;
        Iterator it = validPeers.iterator();
        while ( !validPeer && it.hasNext() ) {
            allowedPeer = it.next();
            if ( peer == null && allowedPeer == null ) {
                validPeer = true;
            } else if ( allowedPeer != null && ((Class) allowedPeer).isInstance( peer ) ) {
                validPeer = true;
            }
        }
        if ( !validPeer ) {
            throw new SAXParseException( "<" + localName + "> is after an invalid element",
                                         getLocator() );
        }

        if ( !allowNesting ) {
            it = this.parents.iterator();
            while ( !invalidNesting && it.hasNext() ) {
                if ( nodeClass.isInstance( it.next() ) ) {
                    invalidNesting = true;
                }
            }
        }
        if ( invalidNesting ) {
            throw new SAXParseException( "<" + localName + ">  may not be nested",
                                         getLocator() );
        }

    }

    /**
     * Start a configuration node.
     *
     * @param name
     *            Tag name.
     * @param attrs
     *            Tag attributes.
     */
    protected void startConfiguration(final String name,
                                      final Attributes attrs) {
        this.characters = new StringBuffer();

        final DefaultConfiguration config = new DefaultConfiguration( name );

        final int numAttrs = attrs.getLength();

        for ( int i = 0; i < numAttrs; ++i ) {
            config.setAttribute( attrs.getLocalName( i ),
                                 attrs.getValue( i ) );
        }

        // lets add the namespaces as attributes
        for ( final Iterator iter = this.namespaces.entrySet().iterator(); iter.hasNext(); ) {
            final Map.Entry entry = (Map.Entry) iter.next();
            String ns = (String) entry.getKey();
            final String value = (String) entry.getValue();
            if ( ns == null || ns.length() == 0 ) {
                ns = "xmlns";
            } else {
                ns = "xmlns:" + ns;
            }
            config.setAttribute( ns,
                                 value );
        }

        if ( this.configurationStack.isEmpty() ) {
            this.configurationStack.addLast( config );
        } else {
            ((DefaultConfiguration) this.configurationStack.getLast()).addChild( config );
            this.configurationStack.addLast( config );
        }
    }

    Handler getHandler(final String localName) {
        return (Handler) this.handlers.get( localName );
    }

    /**
     * @param chars
     * @param start
     * @param len
     * @see org.xml.sax.ContentHandler
     */
    public void characters(final char[] chars,
                           final int start,
                           final int len) {
        if ( this.characters != null ) {
            this.characters.append( chars,
                                    start,
                                    len );
        }
    }

    /**
     * End a configuration node.
     *
     * @return The configuration.
     */
    protected Configuration endConfiguration() {
        final DefaultConfiguration config = (DefaultConfiguration) this.configurationStack.removeLast();
        if ( this.characters != null ) {
            config.setText( this.characters.toString() );
        }

        this.characters = null;

        return config;
    }

    LinkedList getParents() {
        return this.parents;
    }

    Object getParent(final Class parent) {
        final ListIterator it = this.parents.listIterator( this.parents.size() );
        Object node = null;
        while ( it.hasPrevious() ) {
            node = it.previous();
            if ( parent.isInstance( node ) ) {
                break;
            }
        }
        return node;
    }

    Object getPeer() {
        return this.peer;
    }

    Object getCurrent() {
        return this.current;
    }

    public InputSource resolveEntity(final String publicId,
                                     final String systemId) throws SAXException {
        try {
            final InputSource inputSource = resolveSchema( publicId,
                                                     systemId );
            if ( inputSource != null ) {
                return inputSource;
            }
            if ( this.entityResolver != null ) {
                return this.entityResolver.resolveEntity( publicId,
                                                     systemId );
            }
        } catch ( final IOException ioe ) {
        }
        return null;
    }

    public void startPrefixMapping(final String prefix,
                                   final String uri) throws SAXException {
        super.startPrefixMapping( prefix,
                                  uri );
        this.namespaces.put( prefix,
                        uri );
    }

    public void endPrefixMapping(final String prefix) throws SAXException {
        super.endPrefixMapping( prefix );
        this.namespaces.remove( prefix );
    }

    private void print(final SAXParseException x) {
        final String msg = this.message.format( new Object[]{x.getSystemId(), new Integer( x.getLineNumber() ), new Integer( x.getColumnNumber() ), x.getMessage()} );
        System.out.println( msg );
    }

    public void warning(final SAXParseException x) {
        print( x );
    }

    public void error(final SAXParseException x) {
        print( x );
    }

    public void fatalError(final SAXParseException x) throws SAXParseException {
        print( x );
        throw x;
    }

    private InputSource resolveSchema(final String publicId,
                                      final String systemId) throws SAXException,
                                                      IOException {
        // Schema files must end with xsd
        if ( !systemId.toLowerCase().endsWith( "xsd" ) ) {
            return null;
        }

        // try the actual location given by systemId
        try {
            final URL url = new URL( systemId );
            return new InputSource( url.openStream() );
        } catch ( final Exception e ) {
        }

        // Try and get the index for the filename, else return null
        String xsd;
        int index = systemId.lastIndexOf( "/" );
        if ( index == -1 ) {
            index = systemId.lastIndexOf( "\\" );
        }
        if ( index != -1 ) {
            xsd = systemId.substring( index + 1 );
        } else {
            xsd = systemId;
        }

        ClassLoader cl = Thread.currentThread().getContextClassLoader();

        if ( cl == null ) {
            cl = XmlPackageReader.class.getClassLoader();
        }

        // Try looking in META-INF

        {
            final InputStream is = cl.getResourceAsStream( "META-INF/" + xsd );
            if ( is != null ) {
                return new InputSource( is );
            }
        }

        // Try looking in /META-INF
        {
            final InputStream is = cl.getResourceAsStream( "/META-INF/" + xsd );
            if ( is != null ) {
                return new InputSource( is );
            }
        }

        // Try looking at root of classpath
        {
            final InputStream is = cl.getResourceAsStream( "/" + xsd );
            if ( is != null ) {
                return new InputSource( is );
            }
        }

        // Try current working directory
        {
            final File file = new File( xsd );
            if ( file.exists() ) {
                return new InputSource( new BufferedInputStream( new FileInputStream( file ) ) );
            }
        }

        cl = ClassLoader.getSystemClassLoader();

        // Try looking in META-INF
        {
            final InputStream is = cl.getResourceAsStream( "META-INF/" + xsd );
            if ( is != null ) {
                return new InputSource( is );
            }
        }

        // Try looking in /META-INF
        {
            final InputStream is = cl.getResourceAsStream( "/META-INF/" + xsd );
            if ( is != null ) {
                return new InputSource( is );
            }
        }

        // Try looking at root of classpath
        {
            final InputStream is = cl.getResourceAsStream( "/" + xsd );
            if ( is != null ) {
                return new InputSource( is );
            }
        }

        return null;
    }

    /**
     * Intializes EntityResolver that is configured via system property ENTITY_RESOLVER_PROPERTY_NAME.
     */
    private void initEntityResolver() {
        final String entityResolveClazzName = System.getProperty( XmlPackageReader.ENTITY_RESOLVER_PROPERTY_NAME );
        if ( entityResolveClazzName != null && entityResolveClazzName.length() > 0 ) {
            try {
                final Class entityResolverClazz = Thread.currentThread().getContextClassLoader().loadClass( entityResolveClazzName );
                this.entityResolver = (EntityResolver) entityResolverClazz.newInstance();
            } catch ( final Exception ignoreIt ) {
            }
        }
    }

}