/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jasper.compiler;
import java.util.*;
import java.io.*;
import javax.servlet.ServletContext;
import org.apache.jasper.Constants;
import org.apache.jasper.JasperException;
import org.apache.jasper.xmlparser.ParserUtils;
import org.apache.jasper.xmlparser.TreeNode;
import org.apache.jasper.compiler.tagplugin.TagPlugin;
import org.apache.jasper.compiler.tagplugin.TagPluginContext;
/**
* Manages tag plugin optimizations.
* @author Kin-man Chung
*/
public class TagPluginManager {
private static final String TAG_PLUGINS_XML = "/WEB-INF/tagPlugins.xml";
private static final String TAG_PLUGINS_ROOT_ELEM = "tag-plugins";
private boolean initialized = false;
private HashMap tagPlugins = null;
private ServletContext ctxt;
private PageInfo pageInfo;
public TagPluginManager(ServletContext ctxt) {
this.ctxt = ctxt;
}
public void apply(Node.Nodes page, ErrorDispatcher err, PageInfo pageInfo)
throws JasperException {
init(err);
if (tagPlugins == null || tagPlugins.size() == 0) {
return;
}
this.pageInfo = pageInfo;
page.visit(new Node.Visitor() {
public void visit(Node.CustomTag n)
throws JasperException {
invokePlugin(n);
visitBody(n);
}
});
}
private void init(ErrorDispatcher err) throws JasperException {
if (initialized)
return;
InputStream is = ctxt.getResourceAsStream(TAG_PLUGINS_XML);
if (is == null)
return;
String blockExternalString = ctxt.getInitParameter(
Constants.XML_BLOCK_EXTERNAL_INIT_PARAM);
boolean blockExternal;
if (blockExternalString == null) {
blockExternal = true;
} else {
blockExternal = Boolean.parseBoolean(blockExternalString);
}
ParserUtils pu = new ParserUtils(false, blockExternal);
TreeNode root = pu.parseXMLDocument(TAG_PLUGINS_XML, is);
if (root == null) {
return;
}
if (!TAG_PLUGINS_ROOT_ELEM.equals(root.getName())) {
err.jspError("jsp.error.plugin.wrongRootElement", TAG_PLUGINS_XML,
TAG_PLUGINS_ROOT_ELEM);
}
tagPlugins = new HashMap();
Iterator pluginList = root.findChildren("tag-plugin");
while (pluginList.hasNext()) {
TreeNode pluginNode = (TreeNode) pluginList.next();
TreeNode tagClassNode = pluginNode.findChild("tag-class");
if (tagClassNode == null) {
// Error
return;
}
String tagClass = tagClassNode.getBody().trim();
TreeNode pluginClassNode = pluginNode.findChild("plugin-class");
if (pluginClassNode == null) {
// Error
return;
}
String pluginClassStr = pluginClassNode.getBody();
TagPlugin tagPlugin = null;
try {
Class pluginClass = Class.forName(pluginClassStr);
tagPlugin = (TagPlugin) pluginClass.newInstance();
} catch (Exception e) {
throw new JasperException(e);
}
if (tagPlugin == null) {
return;
}
tagPlugins.put(tagClass, tagPlugin);
}
initialized = true;
}
/**
* Invoke tag plugin for the given custom tag, if a plugin exists for
* the custom tag's tag handler.
*
* The given custom tag node will be manipulated by the plugin.
*/
private void invokePlugin(Node.CustomTag n) {
TagPlugin tagPlugin = (TagPlugin)
tagPlugins.get(n.getTagHandlerClass().getName());
if (tagPlugin == null) {
return;
}
TagPluginContext tagPluginContext = new TagPluginContextImpl(n, pageInfo);
n.setTagPluginContext(tagPluginContext);
tagPlugin.doTag(tagPluginContext);
}
static class TagPluginContextImpl implements TagPluginContext {
private Node.CustomTag node;
private Node.Nodes curNodes;
private PageInfo pageInfo;
private HashMap pluginAttributes;
TagPluginContextImpl(Node.CustomTag n, PageInfo pageInfo) {
this.node = n;
this.pageInfo = pageInfo;
curNodes = new Node.Nodes();
n.setAtETag(curNodes);
curNodes = new Node.Nodes();
n.setAtSTag(curNodes);
n.setUseTagPlugin(true);
pluginAttributes = new HashMap();
}
public TagPluginContext getParentContext() {
Node parent = node.getParent();
if (! (parent instanceof Node.CustomTag)) {
return null;
}
return ((Node.CustomTag) parent).getTagPluginContext();
}
public void setPluginAttribute(String key, Object value) {
pluginAttributes.put(key, value);
}
public Object getPluginAttribute(String key) {
return pluginAttributes.get(key);
}
public boolean isScriptless() {
return node.getChildInfo().isScriptless();
}
public boolean isConstantAttribute(String attribute) {
Node.JspAttribute attr = getNodeAttribute(attribute);
if (attr == null)
return false;
return attr.isLiteral();
}
public String getConstantAttribute(String attribute) {
Node.JspAttribute attr = getNodeAttribute(attribute);
if (attr == null)
return null;
return attr.getValue();
}
public boolean isAttributeSpecified(String attribute) {
return getNodeAttribute(attribute) != null;
}
public String getTemporaryVariableName() {
return node.getRoot().nextTemporaryVariableName();
}
public void generateImport(String imp) {
pageInfo.addImport(imp);
}
public void generateDeclaration(String id, String text) {
if (pageInfo.isPluginDeclared(id)) {
return;
}
curNodes.add(new Node.Declaration(text, node.getStart(), null));
}
public void generateJavaSource(String sourceCode) {
curNodes.add(new Node.Scriptlet(sourceCode, node.getStart(),
null));
}
public void generateAttribute(String attributeName) {
curNodes.add(new Node.AttributeGenerator(node.getStart(),
attributeName,
node));
}
public void dontUseTagPlugin() {
node.setUseTagPlugin(false);
}
public void generateBody() {
// Since we'll generate the body anyway, this is really a nop,
// except for the fact that it lets us put the Java sources the
// plugins produce in the correct order (w.r.t the body).
curNodes = node.getAtETag();
}
private Node.JspAttribute getNodeAttribute(String attribute) {
Node.JspAttribute[] attrs = node.getJspAttributes();
for (int i=0; attrs != null && i < attrs.length; i++) {
if (attrs[i].getName().equals(attribute)) {
return attrs[i];
}
}
return null;
}
}
}