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.IMarkupWriter;
026    import org.apache.tapestry.IRequestCycle;
027    import org.apache.tapestry.IScript;
028    import org.apache.tapestry.PageRenderSupport;
029    import org.apache.tapestry.Tapestry;
030    import org.apache.tapestry.TapestryUtils;
031    import org.apache.tapestry.engine.IScriptSource;
032    
033    /**
034     * Works with the {@link Body}component to add a script (and perhaps some initialization) to the
035     * HTML response. [ <a href="../../../../../ComponentReference/Script.html">Component Reference
036     * </a>]
037     * 
038     * @author Howard Lewis Ship
039     */
040    
041    public abstract class Script extends AbstractComponent
042    {
043        /**
044         * Injected
045         * 
046         * @since 4.0
047         */
048    
049        public abstract IScriptSource getScriptSource();
050    
051        /**
052         * A Map of input and output symbols visible to the body of the Script.
053         * 
054         * @since 2.2
055         */
056    
057        private Map _symbols;
058    
059        /**
060         * Constructs the symbols {@link Map}. This starts with the contents of the symbols parameter
061         * (if specified) to which is added any informal parameters. If both a symbols parameter and
062         * informal parameters are bound, then a copy of the symbols parameter's value is made (that is,
063         * the {@link Map}provided by the symbols parameter is read, but not modified).
064         */
065    
066        private Map getInputSymbols()
067        {
068            Map result = new HashMap();
069    
070            Map baseSymbols = getBaseSymbols();
071    
072            if (baseSymbols != null)
073                result.putAll(baseSymbols);
074    
075            // Now, iterate through all the binding names (which includes both
076            // formal and informal parmeters). Skip the formal ones and
077            // access the informal ones.
078    
079            Iterator i = getBindingNames().iterator();
080            while (i.hasNext())
081            {
082                String bindingName = (String) i.next();
083    
084                // Skip formal parameters
085    
086                if (getSpecification().getParameter(bindingName) != null)
087                    continue;
088    
089                IBinding binding = getBinding(bindingName);
090    
091                Object value = binding.getObject();
092    
093                result.put(bindingName, value);
094            }
095    
096            return result;
097        }
098    
099        /**
100         * Gets the {@link IScript}for the correct script.
101         */
102    
103        private IScript getParsedScript()
104        {
105            String scriptPath = getScriptPath();
106    
107            if (scriptPath == null)
108                throw Tapestry.createRequiredParameterException(this, "scriptPath");
109    
110            IScriptSource source = getScriptSource();
111    
112            // If the script path is relative, it should be relative to the Script component's
113            // container (i.e., relative to a page in the application).
114    
115            Resource rootLocation = getContainer().getSpecification().getSpecificationLocation();
116            Resource scriptLocation = rootLocation.getRelativeResource(scriptPath);
117    
118            try
119            {
120                return source.getScript(scriptLocation);
121            }
122            catch (RuntimeException ex)
123            {
124                throw new ApplicationRuntimeException(ex.getMessage(), this, getBinding("script")
125                        .getLocation(), ex);
126            }
127    
128        }
129    
130        protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
131        {
132            if (!cycle.isRewinding())
133            {
134                PageRenderSupport pageRenderSupport = TapestryUtils.getPageRenderSupport(cycle, this);
135    
136                _symbols = getInputSymbols();
137    
138                getParsedScript().execute(cycle, pageRenderSupport, _symbols);
139            }
140    
141            // Render the body of the Script;
142            renderBody(writer, cycle);
143        }
144    
145        public abstract String getScriptPath();
146    
147        // Parameter
148    
149        public abstract Map getBaseSymbols();
150    
151        /**
152         * Returns the complete set of symbols (input and output) from the script execution. This is
153         * visible to the body of the Script, but is cleared after the Script finishes rendering.
154         * 
155         * @since 2.2
156         */
157    
158        public Map getSymbols()
159        {
160            return _symbols;
161        }
162    
163        protected void cleanupAfterRender(IRequestCycle cycle)
164        {
165            _symbols = null;
166    
167            super.cleanupAfterRender(cycle);
168        }
169    
170    }