001    // Copyright 2007 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry.javascript;
016    
017    import java.util.List;
018    
019    import org.apache.tapestry.IAsset;
020    import org.apache.tapestry.IMarkupWriter;
021    import org.apache.tapestry.IPage;
022    import org.apache.tapestry.IRender;
023    import org.apache.tapestry.IRequestCycle;
024    
025    /**
026     * Outputs the main js packages and the tapestry js 
027     * that are defined by the {@link JavascriptManager} service.
028     */
029    public class SimpleAjaxShellDelegate implements IRender
030    {
031        private static final String SYSTEM_NEWLINE = "\n";
032    
033        private JavascriptManager _javascriptManager;
034    
035        public SimpleAjaxShellDelegate(JavascriptManager javascriptManager)
036        {
037            _javascriptManager = javascriptManager;
038        }
039    
040        /**
041         * {@inheritDoc}
042         */
043        public void render(IMarkupWriter writer, IRequestCycle cycle)
044        {        
045            StringBuffer str = new StringBuffer(300);
046            
047            processPath(str, cycle, _javascriptManager.getPath());
048    
049            // include all the main js packages
050            appendAssetsAsJavascript(str, cycle, _javascriptManager.getAssets());
051            
052            IPage page = cycle.getPage();
053            if (page.hasFormComponents())
054            {
055                appendAssetsAsJavascript(str, cycle, _javascriptManager.getFormAssets());
056            }
057            if (page.hasWidgets())
058            {
059                appendAssetsAsJavascript(str, cycle, _javascriptManager.getWidgetAssets());
060            }
061            
062            processTapestryPath(str, cycle, _javascriptManager.getTapestryPath());
063            
064            // include the tapestry js
065            IAsset tapestryAsset = _javascriptManager.getTapestryAsset();
066            if (tapestryAsset!=null)
067            {
068                appendAssetAsJavascript(str, cycle, tapestryAsset);
069            }
070    
071            writer.printRaw(str.toString());
072            writer.println();
073        }
074        
075        /**
076         * Called before including any javascript. It does nothing by default, but allows
077         * subclasses to change this behavior.  
078         * @param cycle
079         * @param str 
080         * @param path The base path to the javascript files. May be null.
081         */
082        protected void processPath(StringBuffer str, IRequestCycle cycle, IAsset path) 
083        {
084        }  
085        
086        /**
087         * Called before including tapestry's base javascript. It does nothing by default, 
088         * but allows subclasses to change this behavior.  
089         * @param cycle
090         * @param str 
091         * @param path The base path to the tapestry javascript file. May be null.
092         */    
093        protected void processTapestryPath(StringBuffer str, IRequestCycle cycle, IAsset path) 
094        {
095        }      
096        
097        /**
098         * Appends a script tag to include the given asset. 
099         * @param str
100         * @param cycle
101         * @param asset
102         */
103        protected void appendAssetAsJavascript(StringBuffer str, IRequestCycle cycle, IAsset asset)
104        {
105            final String url = asset.buildURL();
106            str.append("<script type=\"text/javascript\" src=\"").append(url)
107                    .append("\"></script>").append(SYSTEM_NEWLINE);
108            
109        }        
110    
111        private void appendAssetsAsJavascript(StringBuffer str, IRequestCycle cycle, List jsAssets)
112        {
113            for (int i = 0; i < jsAssets.size(); i++)
114            {
115                appendAssetAsJavascript(str, cycle, (IAsset) jsAssets.get(i));
116            }
117        }
118    }