2009/05/20 - Apache Shale has been retired.

 /*

  * 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.

  */

 /*

  * $Id: TemplateConfigBean.java 464373 2006-10-16 04:21:54Z rahul $

  */

 package org.apache.shale.clay.config.beans;

 import java.util.BitSet;

 import java.util.Iterator;

 import java.util.Map;

 import java.util.TreeMap;

 import javax.servlet.ServletContext;

 import org.apache.shale.clay.config.ClayTemplateParser;

 import org.apache.shale.clay.config.Globals;

 /**

  * <p>The second type of top-level object pool.  This implementation

  * is designed to provide Tapestry like template composition.  The

  * top-level {@link ComponentBean} is materialized from a HTML fragment

  * where HTML elements are bound to meta components defined in the

  * XML configuration files and cached by an instance of {@link ComponentConfigBean}

  * </p>

  */

 public class TemplateConfigBean extends ComponentConfigBean {

     /**

      * <p>Returns a {@link ComponentBean} that is materialized

      * using a HTML template fragment.  The <code>templateName</code>

      * is the name of the file relative to the context root of the

      * web application</p>

      * @param templateName name of the markup template

      * @return root component bean for the <code>templateName</code>

      */

     public ComponentBean getElement(String templateName) {

         StringBuffer jsfid = new StringBuffer(templateName);

         if (jsfid.length() > 0 &&  jsfid.charAt(0) != '/') {

           jsfid.insert(0, '/');

         }

         // look for a watcher identified by the template name

         WatchDog watchDog = (WatchDog) watchDogs.get(jsfid.toString());

         //if a watcher doesn't exist, check for a common

         if (watchDog == null) {

             watchDog = (WatchDog) watchDogs.get(Globals.DEFAULT_COMPONENT_CONFIG_WATCHDOG);

         }

         if (watchDog == null || super.getElement(jsfid.toString()) == null) {

            //The first time the page is created, create a watcher

            watchDog = new WatchDog(getConfigDefinitions(jsfid.toString()), jsfid.toString());

            // register by name

            watchDogs.put(watchDog.getName(), watchDog);

            //loads the HTML template the first time and when file

            //has been modified

            watchDog.refresh(false);

            } else {

            //check to see if an existing html template

            //needs reloaded

            watchDog.refresh(false);

         }

         // returns the cached element

         return super.getElement(jsfid.toString());

     }

     /**

      * <p>Returns an integer value use to order the registered {@link ConfigBean} instances

      * with the {@link ConfigBeanFactory}.

      * </p>

      *

      * @return weight value of <code>1</code>

      */

     public int getWeight() {

         return 1;

     }

     /**

      * <p>Overrides the super call to change the condition of the filter.  This

      * {@link ConfigBean} can create components where the id end in the suffix

      * defined in the web deployment descriptor as a initialization parameter with

      * the name defined by <code>Globals.CLAY_HTML_TEMPLATE_SUFFIX</code>  Or, using

      * the default defined by <code>Globals.CLAY_DEFAULT_HTML_TEMPLATE_SUFFIX</code>

      *

      * @param id jsfid

      * @return <code>true</code> if the <code>jsfid</code> can be handled here

      */

     public boolean validMoniker(String id) {

         return id.endsWith(suffixes[0]);

     }

     /**

      * <p>This is an overridden method called from the init method.

      * It loads an instance of the {@link ClayTemplateParser} and

      * establishes a Map collection to hold the resource

      * {@link org.apache.shale.clay.config.beans.ComponentConfigBean$WatchDog}'s.</p>

      */

     protected void loadConfigFiles() {

         parser = new ClayTemplateParser();

         parser.setConfig(this);

         watchDogs = new TreeMap();

     }

     /**

      * <p>The HTML templates are loaded on-demand.  Override this method forcing the auto

      * load option on.  The XML configuration files are only effected by the

      * <code>auto-reload-clay-files</code> initialization parameter.</p>

      *

      * @param context web container servlet context

      */

     public void init(ServletContext context) {

         super.init(context);

         isWatchDogOn = true;

     }

     /**

      * <p>If the <code>watchDogName</code> equals

      * the {@link ComponentBean} that defines the selected

      * template, remove it.</p>

      *

      * @param watchDogName grouping of template files

      */

     protected void clear(String watchDogName) {

         if (!watchDogName.equals(Globals.DEFAULT_COMPONENT_CONFIG_WATCHDOG)) {

             //unassign a single template component

             ComponentBean b = (ComponentBean) displayElements.get(watchDogName);

             displayElements.remove(watchDogName);

             if (b != null) {

                 try {

                     unassignParent(b);

                 } catch (RuntimeException e1) {

                     // log.error(e1);

                 }

             }

             b = null;

         } else {

            super.clear(watchDogName);

         }

     }

     /**

      * <p>If the <code>forceReload</code> is <code>true</code>,

      * the <code>displayElements</code> cache is invalidated.

      * A <code>true</code> value is returned if cache has

      * been cleared.</p>

      *

      * @param forceReload invalidate the cache flag

      * @return <code>true</code> if the templates were reloaded

      */

     public boolean refresh(boolean forceReload) {

         if (forceReload) {

             //synchronized (displayElements) {

                 //remove all old templates

                 Iterator wi = watchDogs.entrySet().iterator();

                 while (wi.hasNext()) {

                     Map.Entry e = (Map.Entry) wi.next();

                     WatchDog watchDog = (WatchDog) e.getValue();

                     clear(watchDog.getName());

                     if (watchDog != null) {

                         watchDog.destroy();

                     }

                 }

                 watchDogs.clear();

             //}

         }

         return forceReload;

     }

     /**

      * <p>

      * Returns the root metadata component that is used to add to the component

      * tree. It locates the {@link ComponentBean} using the <code>jsfid</code>

      * attribute as the key. A call to the {@link ConfigBeanFactory} locates the

      * correct {@link ConfigBean} used to find the {@link ComponentBean}. </p>

      *

      * @param jsfid parent id of a config bean

      * @return parent config bean

      */

     protected ComponentBean getTopLevelElement(String jsfid) {

         if (validMoniker(jsfid)) {

             return getElement(jsfid);

         }

         //broaden the search to the other ConfigBean's

         ConfigBean config = ConfigBeanFactory.findConfig(jsfid);

         if (config == null) {

             throw new NullPointerException(messages

                     .getMessage("config.notloaded", new Object[] { jsfid }));

         }

         if (config == this) {

             throw new NullPointerException(messages.getMessage(

                     "jsfid.notfound", new Object[] { jsfid }));

         }

         // find the top-level display element associated with the subtree

         ComponentBean b = config.getElement(jsfid);

         if (b == null) {

             throw new NullPointerException(messages.getMessage(

                     "jsfid.notfound", new Object[] { jsfid }));

         }

         return b;

     }

     /**

      * <p>Determines if the <code>node</code> is a transient

      * <code>outputText</code> (<strong>verbatim</strong>) component.</p>

      *

      * @param node a config bean that represents a template token

      * @return <code>true</code> if the node is a verbatim node

      */

     private boolean isVerbatim(ComponentBean node) {

         AttributeBean attr = null;

         if ((node.getJsfid().equals("verbatim") || node.getJsfid().equals("f:verbatim"))

              && node.getComponentType().equals("javax.faces.HtmlOutputText")) {

             attr = node.getAttribute("isTransient");

             if (attr != null) {

                 if (attr.getValue() != null && attr.getValue().length() > 0) {

                     return (Character.toLowerCase(attr.getValue().charAt(0)) == 't');

                 }

             }

         }

         return false;

     }

     /**

      * <p>Recursively walks down the graph of meta-data {@link ComponentBean}'s

      * looking at the children of the <code>root</code>.  Adjacent

      * children that are both <code>verbatim</code> component

      * definitions are merged.  If there is only one child and

      * the child and root nodes are both <code>verbatim</code>

      * definitions, the child is merged up to the root.</p>

      *

      * @param root top config bean that represents a markup template

      */

     public void optimizeTree(ComponentBean root) {

         // children is a TreeSet that is returned as a Collection.

         int size = root.getChildren().size();

         ComponentBean[] children = new ComponentBean[size];

         BitSet verbatimSet = new BitSet(size);

         verbatimSet.clear(0, size);

         StringBuffer buff = new StringBuffer();

         int i = 0;

         Iterator ci = root.getChildrenIterator();

         while (ci.hasNext()) {

             children[i] = (ComponentBean) ci.next();

             if (isVerbatim(children[i])) {

                 verbatimSet.set(i);

             }

             if (children[i].getChildren().size() > 0) {

                 optimizeTree(children[i]);    // merge children for the top down

                 // starting a the botton of the tree.

             }

             i++;

         }

         int s = -1;

         while ((s = verbatimSet.nextSetBit(++s)) > -1) {

             merge: for (int j = s + 1; j < children.length; j++) {

                 if (verbatimSet.get(j)) {

                     buff.setLength(0);

                     // grap the value attribute of the first one in the stack

                     // and concat to a buffer

                     AttributeBean attrTop = children[s].getAttribute("value");

                     if (attrTop != null) {

                         if (attrTop.getValue() != null) {

                             buff.append(attrTop.getValue());

                         }

                     } else {

                         break merge;   // a verbatim without a value should never happen

                     }

                     AttributeBean attrNext = children[j].getAttribute("value");  // the next in sequence to be merged

                     if (attrNext != null) {

                         if (attrNext.getValue() != null) {

                             buff.append(attrNext.getValue());

                         }

                     } else {

                         continue merge;   // a verbatim without a value should never happen

                     }

                     // merge node values

                     attrTop.setValue(buff.toString());

                     root.getChildren().remove(children[j]); // delete the node after merge from the parent

                 } else {

                     // the verbatims are not in sequence (true, false, true)

                     s = j;

                     break merge;

                 }

             }

         }

         // if the root is a verbatim and the only child is a verbatim

         // merge up to the root

         if (isVerbatim(root) && root.getChildren().size() == 1

                 && isVerbatim(children[0])) {

             buff.setLength(0);

             // grap the value attribute of the first one in the stack

             // and concat to a buffer

             AttributeBean attrTop = root.getAttribute("value");

             if (attrTop != null) {

                 if (attrTop.getValue() != null) {

                     buff.append(attrTop.getValue());

                 }

                 AttributeBean attrNext = children[0].getAttribute("value");  // the next in sequence to be merged

                 if (attrNext != null) {

                     if (attrNext.getValue() != null) {

                         buff.append(attrNext.getValue());

                     }

                 }

                 // merge node values

                 attrTop.setValue(buff.toString());

                 root.getChildren().clear(); // delete the node after merge from the parent

             }

         }

     }

 }