Class TagPluginManager

java/org/apache/jasper/compiler/TagPluginManager.java:37–278

Manages tag plugin optimizations.

 * Manages tag plugin optimizations.
 */
public class TagPluginManager {

    private static final String META_INF_JASPER_TAG_PLUGINS_XML = "META-INF/org.apache.jasper/tagPlugins.xml";
    private static final String TAG_PLUGINS_XML = "/WEB-INF/tagPlugins.xml";
    private final ServletContext ctxt;
    private HashMap<String,TagPlugin> tagPlugins;
    private volatile boolean initialized = false;

    /**
     * Creates a new TagPluginManager for the given servlet context.
     *
     * @param ctxt the servlet context
     */
    public TagPluginManager(ServletContext ctxt) {
        this.ctxt = ctxt;
    }

    /**
     * Applies tag plugin optimizations to the given page.
     *
     * @param page the page node tree
     * @param err the error dispatcher
     * @param pageInfo page information
     * @throws JasperException if an error occurs during optimization
     */
    public void apply(Node.Nodes page, ErrorDispatcher err, PageInfo pageInfo) throws JasperException {

        if (!initialized) {
            init(err);
        }
        if (!tagPlugins.isEmpty()) {
            page.visit(new NodeVisitor(this, pageInfo));
        }
    }

    private synchronized void init(ErrorDispatcher err) throws JasperException {
        if (initialized) {
            return;
        }

        String blockExternalString = ctxt.getInitParameter(Constants.XML_BLOCK_EXTERNAL_INIT_PARAM);
        boolean blockExternal;
        if (blockExternalString == null) {
            blockExternal = true;
        } else {
            blockExternal = Boolean.parseBoolean(blockExternalString);
        }

        TagPluginParser parser;
        Thread currentThread = Thread.currentThread();
        ClassLoader original = currentThread.getContextClassLoader();
        try {
            currentThread.setContextClassLoader(TagPluginManager.class.getClassLoader());

            parser = new TagPluginParser(ctxt, blockExternal);

            Enumeration<URL> urls = ctxt.getClassLoader().getResources(META_INF_JASPER_TAG_PLUGINS_XML);
            while (urls.hasMoreElements()) {