nodelistmodel.java

freemaker安装软件

     *     <tr>
     *       <td><tt>_filterType</tt></td>
     *       <td>is a filter-by-type template method model. When called, it 
     *         will yield a node list that contains only those current nodes 
     *         whose type matches one of types passed as argument. You can pass
     *         as many string arguments as you want, each representing one of
     *         the types to select: &quot;attribute&quot;, &quot;cdata&quot;,
     *         &quot;comment&quot;, &quot;document&quot;, 
     *         &quot;documentType&quot;, &quot;element&quot;, 
     *         &quot;entity&quot;, &quot;entityReference&quot;,
     *         &quot;namespace&quot;, &quot;processingInstruction&quot;, or
     *         &quot;text&quot;.</td>
     *     </tr>
     *     <tr>
     *       <td><tt>_name</tt></td>
     *       <td>the names of current nodes, one string per node 
     *         (non-recursive). Applicable to elements and attributes 
     *         (returns their local names), entity references, processing 
     *         instructions (returns its target), doctypes (returns its public
     *         ID)</td>
     *     </tr>
     *     <tr>
     *       <td><tt>_nsprefix</tt></td>
     *       <td>the namespace prefixes of current nodes, one string per node 
     *         (non-recursive). Applicable to elements and attributes</td>
     *     </tr>
     *     <tr>
     *       <td><tt>_nsuri</tt></td>
     *       <td>the namespace URIs of current nodes, one string per node 
     *       (non-recursive). Applicable to elements and attributes</td>
     *     </tr>
     *     <tr>
     *       <td><tt>_parent</tt></td>
     *       <td>parent elements of current nodes. Applicable to element, 
     *       attribute, comment, entity, processing instruction.</td>
     *     </tr>
     *     <tr>
     *       <td><tt>_qname</tt></td>
     *       <td>the qualified names of current nodes in 
     *         <tt>[namespacePrefix:]localName</tt> form, one string per node 
     *         (non-recursive). Applicable to elements and attributes</td>
     *     </tr>
     *     <tr>
     *       <td><tt>_registerNamespace(prefix, uri)</tt></td>
     *       <td>register a XML namespace with the specified prefix and URI for
     *         the current node list and all node lists that are derived from 
     *         the current node list. After registering, you can use the
     *         <tt>nodelist[&quot;prefix:localname&quot;]</tt> or 
     *         <tt>nodelist[&quot;@prefix:localname&quot;]</tt> syntaxes to 
     *         reach elements and attributes whose names are namespace-scoped.
     *         Note that the namespace prefix need not match the actual prefix 
     *         used by the XML document itself since namespaces are compared 
     *         solely by their URI.</td>
     *     </tr>
     *     <tr>
     *       <td><tt>_text</tt></td>
     *       <td>the text of current nodes, one string per node 
     *         (non-recursive). Applicable to elements, attributes, comments, 
     *         processing instructions (returns its data) and CDATA sections. 
     *         The reserved XML characters ('&lt;' and '&amp;') are NOT 
     *         escaped.</td>
     *     </tr>
     *     <tr>
     *       <td><tt>_type</tt></td>
     *       <td>Returns a string describing the type of nodes, one
     *         string per node. The returned values are &quot;attribute&quot;,
     *         &quot;cdata&quot;, &quot;comment&quot;, &quot;document&quot;,
     *         &quot;documentType&quot;, &quot;element&quot;, 
     *         &quot;entity&quot;, &quot;entityReference&quot;, 
     *         &quot;namespace&quot;, &quot;processingInstruction&quot;, 
     *         &quot;text&quot;, or &quot;unknown&quot;.</td>
     *     </tr>
     *     <tr>
     *       <td><tt>_unique</tt></td>
     *       <td>a copy of the current nodes that keeps only the first 
     *         occurrence of every node, eliminating duplicates. Duplicates can
     *         occur in the node list by applying uptree-traversals 
     *         <tt>_parent</tt>, <tt>_ancestor</tt>, <tt>_ancestorOrSelf</tt>,
     *         and <tt>_document</tt> on a node list with multiple elements. 
     *         I.e. <tt>foo._children._parent</tt> will return a node list that
     *         has duplicates of nodes in foo - each node will have the number 
     *         of occurrences equal to the number of its children. In these 
     *         cases, use <tt>foo._children._parent._unique</tt> to eliminate 
     *         duplicates. Applicable to all node types.</td>
     *     </tr>
     *     <tr>
     *       <td>any other key</td>
     *       <td>element children of current nodes with name matching the key. 
     *       This allows for convenience child traversal in 
     *       <tt>book.chapter.title</tt> style syntax. Applicable to document 
     *       and element nodes.</td>
     *     </tr>
     *   </tbody>
     * </table>
     * @return a new NodeListModel containing the nodes that result from applying
     * the operator to this model's nodes.
     * @see freemarker.template.TemplateHashModel#get(String)
     */
    public TemplateModel get(String key) throws TemplateModelException {
        // Try a built-in navigator operator
        NodeOperator op = navigator.getOperator(key);
        String localName = null;
        String namespaceUri = "";
        // If not a nav op, then check for special keys.
        if(op == null && key.length() > 0 && key.charAt(0) == '_') {
            if(key.equals("_unique")) {
                return deriveModel(removeDuplicates(nodes));
            }
            else if(key.equals("_filterType") || key.equals("_ftype")) {
                return new FilterByType();
            }
            else if(key.equals("_registerNamespace")) {
                if(namespaces.isShared()) {
                    namespaces = (Namespaces)namespaces.clone();
                }
            }
        }
        // Last, do a named child element or attribute lookup 
        if(op == null) {
            int colon = key.indexOf(':');
            if(colon == -1) {
                // No namespace prefix specified
                localName = key;
            }
            else {
                // Namespace prefix specified
                localName = key.substring(colon + 1);
                String prefix = key.substring(0, colon);
                namespaceUri = namespaces.translateNamespacePrefixToUri(prefix);
                if(namespaceUri == null) {
                    throw new TemplateModelException("Namespace prefix " + prefix + " is not registered.");
                }
            }
            if(localName.charAt(0) == '@') {
                op = navigator.getAttributeOperator();
                localName = localName.substring(1);
            }
            else {
                op = navigator.getChildrenOperator();
            }
        }
        List result = new ArrayList();
        for (Iterator iter = nodes.iterator(); iter.hasNext();) {
            try {
                op.process(iter.next(), localName, namespaceUri, result);
            }
            catch(RuntimeException e) {
                throw new TemplateModelException(e);
            }
        }
        return deriveModel(result);
    }

    /**
     * Returns true if this NodeListModel contains no nodes. 
     * @see freemarker.template.TemplateHashModel#isEmpty()
     */
    public boolean isEmpty() {
        return nodes.isEmpty();
    }

    /**
     * Registers a namespace prefix-URI pair for subsequent use in {@link
     * #get(String)} as well as for use in XPath expressions.
     * @param prefix the namespace prefix to use for the namespace
     * @param uri the namespace URI that identifies the namespace.
     */
    public void registerNamespace(String prefix, String uri) {
        if(namespaces.isShared()) {
            namespaces = (Namespaces)namespaces.clone();
        }
        namespaces.registerNamespace(prefix, uri);
    }
    
    private class FilterByType
    implements
        TemplateMethodModel
    {
        public Object exec(List arguments)
        {
            List filteredNodes = new ArrayList();
            for (Iterator iter = arguments.iterator(); iter.hasNext();)
            {
                Object node = iter.next();
                if(arguments.contains(navigator.getType(node))) {
                    filteredNodes.add(node);
                }
            }
            return deriveModel(filteredNodes);
        }
    }

    private static final List removeDuplicates(List list)
    {
        int s = list.size();
        ArrayList ulist = new ArrayList(s);
        Set set = new HashSet(s * 4 / 3, .75f);
        Iterator it = list.iterator();
        while (it.hasNext()) {
            Object o = it.next();
            if (set.add(o)) {
                ulist.add(o);
            }
        }
        return ulist;
    }

    private static Class getClass(String className) {
        try {
            return ClassUtil.forName(className);
        }
        catch(Exception e) {
            if(logger.isDebugEnabled()) {
                logger.debug("Couldn't load class " + className, e);
            }
            return null;
        }
    }
    
    private static Namespaces.Factory getNamespacesFactory() {
        Namespaces.Factory factory = getNamespacesFactory("JaxenNamespaces");
        if(factory == null) {
            factory = getNamespacesFactory("Namespaces");
        }
        return factory;
    }
    
    private static Namespaces.Factory getNamespacesFactory(String clazz) {
        try {
            return (Namespaces.Factory)
                ClassUtil.forName("freemarker.ext.xml." + clazz)
                    .getDeclaredField("FACTORY").get(null);
        }
        catch(Throwable t) {
            if(logger.isDebugEnabled()) {
                logger.debug("Could not load " + clazz, t);
            }
            return null;
        }
    }
    
    private static Navigator getNavigator(String navType) {
        try {
            Navigator nav =  
                (Navigator) ClassUtil.forName("freemarker.ext.xml." + navType + "Navigator")
                    .getDeclaredConstructor(new Class[] {}).newInstance(new Object[] {});
            return nav;
        }
        catch(Throwable t) {
            if(logger.isDebugEnabled()) {
                logger.debug("Could not load navigator for " + navType, t);
            }
            return null;
        }
    }

    public TemplateSequenceModel getChildNodes() throws TemplateModelException
    {
        return (TemplateSequenceModel)get("_content");
    }

    public String getNodeName() throws TemplateModelException
    {
        return getUniqueText((NodeListModel)get("_name"), "name");
    }

    public String getNodeNamespace() throws TemplateModelException
    {
        return getUniqueText((NodeListModel)get("_nsuri"), "namespace");
    }

    public String getNodeType() throws TemplateModelException
    {
        return getUniqueText((NodeListModel)get("_type"), "type");
    }
    public TemplateNodeModel getParentNode() throws TemplateModelException
    {
        return (TemplateNodeModel)get("_parent"); 
    }

    private String getUniqueText(NodeListModel model, String property) throws TemplateModelException {
        String s1 = null;
        Set s = null;
        for(Iterator it = model.nodes.iterator(); it.hasNext();) {
            String s2 = (String)it.next();
            if(s2 != null) {
                // No text yet, make this text the current text
                if(s1 == null) {
                    s1 = s2;
                }
                // else if there's already a text and they differ, start 
                // accumulating them for an error message
                else if(!s1.equals(s2)) {
                    if(s == null) {
                        s = new HashSet();
                        s.add(s1);
                    }
                    s.add(s2);
                }
            }
        }
        // If the set for the error messages is empty, return the retval
        if(s == null) {
            return s1;
        }
        // Else throw an exception signaling ambiguity
        throw new TemplateModelException(
            "Value for node " + property + " is ambiguos: " + s);
    }
}