readerutils.java

电子地图服务器,搭建自己的地图服务

        return value;
    }

    /**
     * getBooleanAttribute purpose.
     *
     * <p>
     * Used to help with XML manipulations. Returns the first child integer
     * attribute of the specified name.  An exception occurs when the node is
     * required and not found.
     * </p>
     *
     * @param elem The root element to look for children in.
     * @param attName The name of the attribute to look for.
     * @param mandatory true when an exception should be thrown if the
     *        attribute element does not exist.
     * @param defaultValue what to return for a non-mandatory that is not
     *        found.
     *
     * @return The value if the attribute was found, the false otherwise.
     *
     * @throws Exception When a child attribute is required and
     *         not found.
     */
    public static boolean getBooleanAttribute(Element elem, String attName, boolean mandatory,
        boolean defaultValue) throws Exception {
        String value = getAttribute(elem, attName, mandatory);

        if ((value == null) || (value == "")) {
            return defaultValue;
        }

        return Boolean.valueOf(value).booleanValue();
    }

    /**
     * getChildText purpose.
     *
     * <p>
     * Used to help with XML manipulations. Returns the first child text value
     * of the specified element name.
     * </p>
     *
     * @param root The root element to look for children in.
     * @param childName The name of the attribute to look for.
     *
     * @return The value if the child was found, the null otherwise.
     */
    public static String getChildText(Element root, String childName) {
        try {
            return getChildText(root, childName, false);
        } catch (Exception ex) {
            return null;
        }
    }

    /**
     * getChildText purpose.
     *
     * <p>
     * Used to help with XML manipulations. Returns the first child text value
     * of the specified element name.  An exception occurs when the node is
     * required and not found.
     * </p>
     *
     * @param root The root element to look for children in.
     * @param childName The name of the attribute to look for.
     * @param mandatory true when an exception should be thrown if the text
     *        does not exist.
     *
     * @return The value if the child was found, the null otherwise.
     *
     * @throws Exception When a child attribute is required and
     *         not found.
     */
    public static String getChildText(Element root, String childName, boolean mandatory)
        throws Exception {
        Element elem = getChildElement(root, childName, mandatory);

        if (elem != null) {
            return getElementText(elem, mandatory);
        } else {
            if (mandatory) {
                String msg = "Mandatory child " + childName + "not found in " + " element: " + root;

                throw new Exception(msg);
            }

            return null;
        }
    }

    /**
     * getChildText purpose.
     *
     * <p>
     * Used to help with XML manipulations. Returns the text value of the
     * specified element name.
     * </p>
     *
     * @param elem The root element to look for children in.
     *
     * @return The value if the text was found, the null otherwise.
     */
    public static String getElementText(Element elem) {
        try {
            return getElementText(elem, false);
        } catch (Exception ex) {
            return null;
        }
    }

    /**
     * getChildText purpose.
     *
     * <p>
     * Used to help with XML manipulations. Returns the text value of the
     * specified element name.  An exception occurs when the node is required
     * and not found.
     * </p>
     *
     * @param elem The root element to look for children in.
     * @param mandatory true when an exception should be thrown if the text
     *        does not exist.
     *
     * @return The value if the text was found, the null otherwise.
     *
     * @throws Exception When text is required and not found.
     */
    public static String getElementText(Element elem, boolean mandatory)
        throws Exception {
        String value = null;

        if (LOGGER.isLoggable(Level.FINER)) {
            LOGGER.finer(new StringBuffer("getting element text for ").append(elem).toString());
        }

        if (elem != null) {
            Node child;

            NodeList childs = elem.getChildNodes();

            int nChilds = childs.getLength();

            for (int i = 0; i < nChilds; i++) {
                child = childs.item(i);

                if (child.getNodeType() == Node.TEXT_NODE) {
                    value = child.getNodeValue();

                    if (mandatory && "".equals(value.trim())) {
                        throw new Exception(elem.getNodeName() + " text is empty");
                    }

                    break;
                }
            }

            if (mandatory && (value == null)) {
                throw new Exception(elem.getNodeName() + " element does not contains text");
            }
        } else {
            throw new Exception("Argument element can't be null");
        }

        return value;
    }

    /**
     * getKeyWords purpose.
     *
     * <p>
     * Used to help with XML manipulations. Returns a list of keywords that
     * were found.
     * </p>
     *
     * @param keywordsElem The root element to look for children in.
     *
     * @return The list of keywords that were found.
     */
    public static List getKeyWords(Element keywordsElem) {
        NodeList klist = keywordsElem.getElementsByTagName("keyword");
        int kCount = klist.getLength();
        List keywords = new ArrayList(kCount);
        String kword;
        Element kelem;

        for (int i = 0; i < kCount; i++) {
            kelem = (Element) klist.item(i);
            kword = getElementText(kelem);

            if (kword != null) {
                keywords.add(kword);
            }
        }

        Object[] s = (Object[]) keywords.toArray();

        if (s == null) {
            return new ArrayList();
        }

        ArrayList ss = new ArrayList(s.length);

        for (int i = 0; i < s.length; i++)
            ss.add(s[i]);

        return ss;
    }

    /**
     * getFirstChildElement purpose.
     *
     * <p>
     * Used to help with XML manipulations. Returns the element which
     * represents the first child.
     * </p>
     *
     * @param root The root element to look for children in.
     *
     * @return The element if a child was found, the null otherwise.
     */
    public static Element getFirstChildElement(Element root) {
        Node child = root.getFirstChild();

        while (child != null) {
            if (child.getNodeType() == Node.ELEMENT_NODE) {
                return (Element) child;
            }

            child = child.getNextSibling();
        }

        return null;
    }

    /**
     * getDoubleAttribute purpose.
     *
     * <p>
     * Used to help with XML manipulations. Returns the first child integer
     * attribute of the specified name.  An exception occurs when the node is
     * required and not found.
     * </p>
     *
     * @param elem The root element to look for children in.
     * @param attName The name of the attribute to look for.
     * @param mandatory true when an exception should be thrown if the
     *        attribute element does not exist.
     *
     * @return The double value if the attribute was found, the NaN otherwise.
     *
     * @throws Exception When a attribute element is required and
     *         not found.
     */
    public static double getDoubleAttribute(Element elem, String attName, boolean mandatory)
        throws Exception {
        String value = getAttribute(elem, attName, mandatory);

        if ((value == null) || (value == "")) {
            return 0.0;
        }

        double d = Double.NaN;

        if (value != null) {
            try {
                d = Double.parseDouble(value);
            } catch (NumberFormatException ex) {
                throw new ConfigurationException("Illegal attribute value for " + attName
                    + " in element " + elem.getNodeName() + ". Expected double, but was " + value);
            }
        }

        return d;
    }
    
    /**
     * Validates an xml document against a specified schema.
     *
     * @param xml The document.
     * @param errorHandler The validation error handler. 
     * @param targetNamespace The target namespace of the schema, may be <code>null</code>
     * @param schemaLocation The location of the schema to validate against, may be <code>null</code>
     *
     * @throws RuntimeException If reader failed to parse properly.
     */
    public static void validate( Document xml, DefaultHandler errorHandler, String targetNamespace, String schemaLocation ) {
        try {
            Transformer tx = TransformerFactory.newInstance().newTransformer();
            ByteArrayOutputStream output = new ByteArrayOutputStream();
            tx.transform( new DOMSource( xml ), new StreamResult( output ) );

            InputStreamReader reader =
                    new InputStreamReader( new ByteArrayInputStream( output.toByteArray() ) );
            validate( reader, errorHandler, targetNamespace, schemaLocation );
        }
        catch( Exception e ) {
                throw new RuntimeException( e );
        }
    }
    
    /**
     * Validates an xml document against a specified schema.
     *
     * @param xml Reader representing xml stream to parse.
     * @param errorHandler The validation error handler. 
     * @param targetNamespace The target namespace of the schema, may be <code>null</code>
     * @param schemaLocation The location of the schema to validate against, may be <code>null</code>
     *
     * @throws RuntimeException If reader failed to parse properly.
     */
    public static void validate ( Reader xml, DefaultHandler errorHandler, String targetNamespace, String schemaLocation ) {
        InputSource in = new InputSource( xml );
        
        try {

            //TODO: pretty sure this doesn't actually do validation
            // ahhh... xml in java....
            SAXParserFactory sf = SAXParserFactory.newInstance();
            sf.setNamespaceAware(true); 
            sf.setValidating(true);            
            SAXParser parser = sf.newSAXParser();
            parser.setProperty(
               "http://java.sun.com/xml/jaxp/properties/schemaLanguage",  
               "http://www.w3.org/2001/XMLSchema");

//            SAXParser parser = SAXParserFactory.newInstance().newSAXParser();
//               parser.setProperty("http://xml.org/sax/features/validation", Boolean.TRUE);
//               
//                parser.setProperty("http://apache.org/xml/features/validation/schema",
//                    Boolean.TRUE);
//                parser.setProperty("http://apache.org/xml/features/validation/schema-full-checking",
//                    Boolean.TRUE);

                if ( schemaLocation != null ) {
                    parser.setProperty("http://java.sun.com/xml/jaxp/properties/schemaSource", schemaLocation);
//                        if ( targetNamespace != null ) {
//                                parser.setProperty("http://apache.org/xml/properties/schema/external-schemaLocation",
//                                    targetNamespace + " " + schemaLocation );   
//                        }
                }
                
                parser.parse( in, errorHandler);
                
            } 
                catch( Exception e ) {
                        String msg = "Error reading : " + xml;
                        throw new RuntimeException ( msg, e );
            }
        }
}