tagfileprocessor.java

业界著名的tomcat服务器的最新6.0的源代码。

                 * name of the variable that is being aliased
                 */
                nameGiven = alias;
                checkUniqueName(nameFromAttribute, VAR_NAME_FROM, n);
                checkUniqueName(alias, VAR_ALIAS, n);
            } else {
                // name-given specified
                checkUniqueName(nameGiven, VAR_NAME_GIVEN, n);
            }

            variableVector.addElement(new TagVariableInfo(nameGiven,
                    nameFromAttribute, className, declare, scope));
        }

        /*
         * Returns the vector of attributes corresponding to attribute
         * directives.
         */
        public Vector getAttributesVector() {
            return attributeVector;
        }

        /*
         * Returns the vector of variables corresponding to variable directives.
         */
        public Vector getVariablesVector() {
            return variableVector;
        }

        /*
         * Returns the value of the dynamic-attributes tag directive attribute.
         */
        public String getDynamicAttributesMapName() {
            return dynamicAttrsMapName;
        }

        public TagInfo getTagInfo() throws JasperException {

            if (name == null) {
                // XXX Get it from tag file name
            }

            if (bodycontent == null) {
                bodycontent = TagInfo.BODY_CONTENT_SCRIPTLESS;
            }

            String tagClassName = JspUtil.getTagHandlerClassName(path, err);

            TagVariableInfo[] tagVariableInfos = new TagVariableInfo[variableVector
                    .size()];
            variableVector.copyInto(tagVariableInfos);

            TagAttributeInfo[] tagAttributeInfo = new TagAttributeInfo[attributeVector
                    .size()];
            attributeVector.copyInto(tagAttributeInfo);

            return new JasperTagInfo(name, tagClassName, bodycontent,
                    description, tagLibInfo, tei, tagAttributeInfo,
                    displayName, smallIcon, largeIcon, tagVariableInfos,
                    dynamicAttrsMapName);
        }

        static class NameEntry {
            private String type;

            private Node node;

            private TagAttributeInfo attr;

            NameEntry(String type, Node node, TagAttributeInfo attr) {
                this.type = type;
                this.node = node;
                this.attr = attr;
            }

            String getType() {
                return type;
            }

            Node getNode() {
                return node;
            }

            TagAttributeInfo getTagAttributeInfo() {
                return attr;
            }
        }

        /**
         * Reports a translation error if names specified in attributes of
         * directives are not unique in this translation unit.
         * 
         * The value of the following attributes must be unique. 1. 'name'
         * attribute of an attribute directive 2. 'name-given' attribute of a
         * variable directive 3. 'alias' attribute of variable directive 4.
         * 'dynamic-attributes' of a tag directive except that
         * 'dynamic-attributes' can (and must) have the same value when it
         * appears in multiple tag directives.
         * 
         * Also, 'name-from' attribute of a variable directive cannot have the
         * same value as that from another variable directive.
         */
        private void checkUniqueName(String name, String type, Node n)
                throws JasperException {
            checkUniqueName(name, type, n, null);
        }

        private void checkUniqueName(String name, String type, Node n,
                TagAttributeInfo attr) throws JasperException {

            HashMap table = (type == VAR_NAME_FROM) ? nameFromTable : nameTable;
            NameEntry nameEntry = (NameEntry) table.get(name);
            if (nameEntry != null) {
                if (type != TAG_DYNAMIC || nameEntry.getType() != TAG_DYNAMIC) {
                    int line = nameEntry.getNode().getStart().getLineNumber();
                    err.jspError(n, "jsp.error.tagfile.nameNotUnique", type,
                            nameEntry.getType(), Integer.toString(line));
                }
            } else {
                table.put(name, new NameEntry(type, n, attr));
            }
        }

        /**
         * Perform miscellean checks after the nodes are visited.
         */
        void postCheck() throws JasperException {
            // Check that var.name-from-attributes has valid values.
            Iterator iter = nameFromTable.keySet().iterator();
            while (iter.hasNext()) {
                String nameFrom = (String) iter.next();
                NameEntry nameEntry = (NameEntry) nameTable.get(nameFrom);
                NameEntry nameFromEntry = (NameEntry) nameFromTable
                        .get(nameFrom);
                Node nameFromNode = nameFromEntry.getNode();
                if (nameEntry == null) {
                    err.jspError(nameFromNode,
                            "jsp.error.tagfile.nameFrom.noAttribute", nameFrom);
                } else {
                    Node node = nameEntry.getNode();
                    TagAttributeInfo tagAttr = nameEntry.getTagAttributeInfo();
                    if (!"java.lang.String".equals(tagAttr.getTypeName())
                            || !tagAttr.isRequired()
                            || tagAttr.canBeRequestTime()) {
                        err.jspError(nameFromNode,
                                "jsp.error.tagfile.nameFrom.badAttribute",
                                nameFrom, Integer.toString(node.getStart()
                                        .getLineNumber()));
                    }
                }
            }
        }
    }

    /**
     * Parses the tag file, and collects information on the directives included
     * in it. The method is used to obtain the info on the tag file, when the
     * handler that it represents is referenced. The tag file is not compiled
     * here.
     * 
     * @param pc
     *            the current ParserController used in this compilation
     * @param name
     *            the tag name as specified in the TLD
     * @param tagfile
     *            the path for the tagfile
     * @param tagLibInfo
     *            the TagLibraryInfo object associated with this TagInfo
     * @return a TagInfo object assembled from the directives in the tag file.
     */
    public static TagInfo parseTagFileDirectives(ParserController pc,
            String name, String path, TagLibraryInfo tagLibInfo)
            throws JasperException {

        ErrorDispatcher err = pc.getCompiler().getErrorDispatcher();

        Node.Nodes page = null;
        try {
            page = pc.parseTagFileDirectives(path);
        } catch (FileNotFoundException e) {
            err.jspError("jsp.error.file.not.found", path);
        } catch (IOException e) {
            err.jspError("jsp.error.file.not.found", path);
        }

        TagFileDirectiveVisitor tagFileVisitor = new TagFileDirectiveVisitor(pc
                .getCompiler(), tagLibInfo, name, path);
        page.visit(tagFileVisitor);
        tagFileVisitor.postCheck();

        return tagFileVisitor.getTagInfo();
    }

    /**
     * Compiles and loads a tagfile.
     */
    private Class loadTagFile(Compiler compiler, String tagFilePath,
            TagInfo tagInfo, PageInfo parentPageInfo) throws JasperException {

        JspCompilationContext ctxt = compiler.getCompilationContext();
        JspRuntimeContext rctxt = ctxt.getRuntimeContext();
        JspServletWrapper wrapper = (JspServletWrapper) rctxt
                .getWrapper(tagFilePath);

        synchronized (rctxt) {
            if (wrapper == null) {
                wrapper = new JspServletWrapper(ctxt.getServletContext(), ctxt
                        .getOptions(), tagFilePath, tagInfo, ctxt
                        .getRuntimeContext(), ctxt.getTagFileJarUrl(tagFilePath));
                rctxt.addWrapper(tagFilePath, wrapper);

                // Use same classloader and classpath for compiling tag files
                wrapper.getJspEngineContext().setClassLoader(
                        (URLClassLoader) ctxt.getClassLoader());
                wrapper.getJspEngineContext().setClassPath(ctxt.getClassPath());
            } else {
                // Make sure that JspCompilationContext gets the latest TagInfo
                // for the tag file. TagInfo instance was created the last
                // time the tag file was scanned for directives, and the tag
                // file may have been modified since then.
                wrapper.getJspEngineContext().setTagInfo(tagInfo);
            }

            Class tagClazz;
            int tripCount = wrapper.incTripCount();
            try {
                if (tripCount > 0) {
                    // When tripCount is greater than zero, a circular
                    // dependency exists. The circularily dependant tag
                    // file is compiled in prototype mode, to avoid infinite
                    // recursion.

                    JspServletWrapper tempWrapper = new JspServletWrapper(ctxt
                            .getServletContext(), ctxt.getOptions(),
                            tagFilePath, tagInfo, ctxt.getRuntimeContext(),
                            ctxt.getTagFileJarUrl(tagFilePath));
                    tagClazz = tempWrapper.loadTagFilePrototype();
                    tempVector.add(tempWrapper.getJspEngineContext()
                            .getCompiler());
                } else {
                    tagClazz = wrapper.loadTagFile();
                }
            } finally {
                wrapper.decTripCount();
            }

            // Add the dependants for this tag file to its parent's
            // dependant list. The only reliable dependency information
            // can only be obtained from the tag instance.
            try {
                Object tagIns = tagClazz.newInstance();
                if (tagIns instanceof JspSourceDependent) {
                    Iterator iter = ((List) ((JspSourceDependent) tagIns)
                            .getDependants()).iterator();
                    while (iter.hasNext()) {
                        parentPageInfo.addDependant((String) iter.next());
                    }
                }
            } catch (Exception e) {
                // ignore errors
            }

            return tagClazz;
        }
    }

    /*
     * Visitor which scans the page and looks for tag handlers that are tag
     * files, compiling (if necessary) and loading them.
     */
    private class TagFileLoaderVisitor extends Node.Visitor {

        private Compiler compiler;

        private PageInfo pageInfo;

        TagFileLoaderVisitor(Compiler compiler) {

            this.compiler = compiler;
            this.pageInfo = compiler.getPageInfo();
        }

        public void visit(Node.CustomTag n) throws JasperException {
            TagFileInfo tagFileInfo = n.getTagFileInfo();
            if (tagFileInfo != null) {
                String tagFilePath = tagFileInfo.getPath();
                JspCompilationContext ctxt = compiler.getCompilationContext();
                if (ctxt.getTagFileJarUrl(tagFilePath) == null) {
                    // Omit tag file dependency info on jar files for now.
                    pageInfo.addDependant(tagFilePath);
                }
                Class c = loadTagFile(compiler, tagFilePath, n.getTagInfo(),
                        pageInfo);
                n.setTagHandlerClass(c);
            }
            visitBody(n);
        }
    }

    /**
     * Implements a phase of the translation that compiles (if necessary) the
     * tag files used in a JSP files. The directives in the tag files are
     * assumed to have been proccessed and encapsulated as TagFileInfo in the
     * CustomTag nodes.
     */
    public void loadTagFiles(Compiler compiler, Node.Nodes page)
            throws JasperException {

        tempVector = new Vector();
        page.visit(new TagFileLoaderVisitor(compiler));
    }

    /**
     * Removed the java and class files for the tag prototype generated from the
     * current compilation.
     * 
     * @param classFileName
     *            If non-null, remove only the class file with with this name.
     */
    public void removeProtoTypeFiles(String classFileName) {
        Iterator iter = tempVector.iterator();
        while (iter.hasNext()) {
            Compiler c = (Compiler) iter.next();
            if (classFileName == null) {
                c.removeGeneratedClassFiles();
            } else if (classFileName.equals(c.getCompilationContext()
                    .getClassFileName())) {
                c.removeGeneratedClassFiles();
                tempVector.remove(c);
                return;
            }
        }
    }
}