001    // Copyright 2004, 2005 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.html;
016    
017    import java.util.HashMap;
018    import java.util.Iterator;
019    import java.util.Map;
020    
021    import org.apache.hivemind.ApplicationRuntimeException;
022    import org.apache.hivemind.Resource;
023    import org.apache.tapestry.AbstractComponent;
024    import org.apache.tapestry.IBinding;
025    import org.apache.tapestry.IEngine;
026    import org.apache.tapestry.IMarkupWriter;
027    import org.apache.tapestry.IRequestCycle;
028    import org.apache.tapestry.IScript;
029    import org.apache.tapestry.PageRenderSupport;
030    import org.apache.tapestry.Tapestry;
031    import org.apache.tapestry.TapestryUtils;
032    import org.apache.tapestry.engine.IScriptSource;
033    
034    /**
035     * Works with the {@link Body}component to add a script (and perhaps some initialization) to the
036     * HTML response. [ <a href="../../../../../ComponentReference/Script.html">Component Reference
037     * </a>]
038     * 
039     * @author Howard Lewis Ship
040     */
041    
042    public abstract class Script extends AbstractComponent
043    {
044        /**
045         * A Map of input and output symbols visible to the body of the Script.
046         * 
047         * @since 2.2
048         */
049    
050        private Map _symbols;
051    
052        /**
053         * Constructs the symbols {@link Map}. This starts with the contents of the symbols parameter
054         * (if specified) to which is added any informal parameters. If both a symbols parameter and
055         * informal parameters are bound, then a copy of the symbols parameter's value is made (that is,
056         * the {@link Map}provided by the symbols parameter is read, but not modified).
057         */
058    
059        private Map getInputSymbols()
060        {
061            Map result = new HashMap();
062    
063            Map baseSymbols = getBaseSymbols();
064    
065            if (baseSymbols != null)
066                result.putAll(baseSymbols);
067    
068            // Now, iterate through all the binding names (which includes both
069            // formal and informal parmeters). Skip the formal ones and
070            // access the informal ones.
071    
072            Iterator i = getBindingNames().iterator();
073            while (i.hasNext())
074            {
075                String bindingName = (String) i.next();
076    
077                // Skip formal parameters
078    
079                if (getSpecification().getParameter(bindingName) != null)
080                    continue;
081    
082                IBinding binding = getBinding(bindingName);
083    
084                Object value = binding.getObject();
085    
086                result.put(bindingName, value);
087            }
088    
089            return result;
090        }
091    
092        /**
093         * Gets the {@link IScript}for the correct script.
094         */
095    
096        private IScript getParsedScript(IRequestCycle cycle)
097        {
098            String scriptPath = getScriptPath();
099    
100            if (scriptPath == null)
101                throw Tapestry.createRequiredParameterException(this, "scriptPath");
102    
103            IEngine engine = cycle.getEngine();
104            IScriptSource source = engine.getScriptSource();
105    
106            // If the script path is relative, it should be relative to the Script component's
107            // container (i.e., relative to a page in the application).
108    
109            Resource rootLocation = getContainer().getSpecification().getSpecificationLocation();
110            Resource scriptLocation = rootLocation.getRelativeResource(scriptPath);
111    
112            try
113            {
114                return source.getScript(scriptLocation);
115            }
116            catch (RuntimeException ex)
117            {
118                throw new ApplicationRuntimeException(ex.getMessage(), this, null, ex);
119            }
120    
121        }
122    
123        protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
124        {
125            if (!cycle.isRewinding())
126            {
127                PageRenderSupport pageRenderSupport = TapestryUtils.getPageRenderSupport(cycle, this);
128    
129                _symbols = getInputSymbols();
130    
131                getParsedScript(cycle).execute(cycle, pageRenderSupport, _symbols);
132            }
133    
134            // Render the body of the Script;
135            renderBody(writer, cycle);
136        }
137    
138        public abstract String getScriptPath();
139    
140        // Parameter
141    
142        public abstract Map getBaseSymbols();
143    
144        /**
145         * Returns the complete set of symbols (input and output) from the script execution. This is
146         * visible to the body of the Script, but is cleared after the Script finishes rendering.
147         * 
148         * @since 2.2
149         */
150    
151        public Map getSymbols()
152        {
153            return _symbols;
154        }
155    
156        protected void cleanupAfterRender(IRequestCycle cycle)
157        {
158            _symbols = null;
159    
160            super.cleanupAfterRender(cycle);
161        }
162    
163    }