Changeset 1495 for MDService2/trunk/MDService2/src/eu/clarin/cmdi/mdservice/action/GenericProxyAction.java

Timestamp:

08/25/11 20:21:23 (13 years ago)

Author:

vronk

Message:

started cleaning up code, adding inline-documentation;
also changes to output method in xsl (xhtml)

File:

• MDService2/trunk/MDService2/src/eu/clarin/cmdi/mdservice/action/GenericProxyAction.java (modified) (13 diffs)

MDService2/trunk/MDService2/src/eu/clarin/cmdi/mdservice/action/GenericProxyAction.java

@@ -26 +26 @@
 
 import org.apache.struts2.interceptor.ServletRequestAware;
-
 import com.opensymphony.xwork2.ActionSupport;
-
 import eu.clarin.cmdi.mdservice.model.Diagnostics;
 
 /**
- * main Struts 2 controller 
- * responds to requests (collections, model, recordset) 
- * by dispatching the requests to appropriate internal methods and filling the inputStream with the result
+ * main Struts2 controller (ie implemenets the struts' execute()-method), all other Actions are derived from.   
+ * Defines the methods used for retrieving the data 
+ * and provides basic implementation where possible.
  *  
  * @author vronk
- *
  */
 public class GenericProxyAction extends ActionSupport 
@@ -69 +66 @@
         private String repository;
         //private Map<String,Object> session;
-         private HttpServletRequest request; 
-         private long duration = 0;
-         
+        private HttpServletRequest request; 
+        private long duration = 0;
+        private InputStream resultStream;
+        private InputStream sourceStream;
+        protected URL base_url ;
+                
          public GenericProxyAction(){
                  super();
@@ -198 +198 @@
         }
 
+        /**
+         * is used in struts.xml to dynamically set the mime-type of the result, depending on the format-parameter
+         * @return
+         */
         public String getActionContentType() {
                 if (format.toLowerCase().startsWith("html")) {
@@ -269 +273 @@
 
         /**
-         * primitive identification of the target-proxy
-         * base for finding the right base_url in the props
+         * internal identification of the target-proxy
+         * base for finding the right base_url in the properties
          * subclass has to override with its specific proxykey
-         * @return
+         * @return the key identifying this type of proxy
          */
         public String getProxyKey() {
@@ -278 +282 @@
         }
         
+        /**
+         * TODO: check what this does, where it is used?
+         * @return
+         */
         public String getUserMsg() {
                 return userMsg;
@@ -286 +294 @@
         }
         
+        /**
+         * TODO: check what this does, where it is used?
+         * @return
+         */
         @Override
         public void setServletRequest(HttpServletRequest arg0) {
@@ -294 +306 @@
                 return request;
         }
-
-
-        private InputStream resultStream;
-        private InputStream sourceStream;
 
         /**
@@ -335 +343 @@
         }
         
-        protected URL base_url ;
-        
+        /**
+         * Reads URI from the configuration (mdservice.properties) based on the proxy-key
+         * @return the base-URI of the target repository or registry
+         */
+        public String getBaseURI() {            
+                String uri =Admin.getConfig().getProperty(getProxyKey() + ".uri");              
+                return uri;
+        }
+
+        /**
+         * Provides the base-URL specific to given target repository or registry 
+         * @return
+         * @throws MalformedURLException
+         */     
         public URL getBaseURL() throws MalformedURLException {          
                 if (base_url == null) {
@@ -344 +364 @@
         }
         
-        public String getBaseURI() {            
-                String uri =Admin.getConfig().getProperty(getProxyKey() + ".uri");              
-                return uri;
-        }
-
-        
+        /**
+         * Constructs the actual URL to be send to the target repository/registry
+         * It has to be overridden by the subclasses 
+         * as every target service has a different request-pattern.  
+         * @return URL of the target request 
+         * @throws IOException
+         */
         public URL getTargetRequest() throws IOException {
-        // URL targetURL =new URL( base_url, compname + ".xml");
-                URL targetURL = getBaseURL();      
-                      
+                URL targetURL = getBaseURL();                      
         return targetURL;
         }
         
-        /*
-        public String getRequestKey() {
-                String key="";
-                if (getActionkey()!=null) {
-                        key += getActionkey() + "//-" ;
-                }
-                if (getQ()!=null) {
-                        key += getQ() + "//-" ;
-                }
-                if (getCollection()!=null) {
-                        key += getCollection();
-                }
-                 
-                return key;
-        }
-*/
-
+        /**
+         * Constructs an unambiguous key for the request (encoding all the parameters).
+         * This is used as identifier for caching 
+         * @return key unambiguously encoding the request
+         */
+        
          public String getRequestKey() {
                         String key="";
@@ -416 +424 @@
                         }else{
                                 key +="//-" ;
-                        }
-                        
+                        }                       
                          
-                        return key;
-        }
+                return key;
+        }
+         
+         
         public InputStream getSourceStream() throws IOException, NoStylesheetException {                
                 return getTargetRequest().openStream();
-                //      Admin.notifyUser(getProxyKey() + ".getSourceStream() - unable to open stream: " + getTargetRequest();  
-        }
-        
+ 
+        }
+        
+        /*
+         * TODO: this should go to Utilities!
+         */
         public  static String convertStreamToString(InputStream is) {  
                 
@@ -677 +689 @@
         }
         
+        /**
+         * This is the work-horse function.
+         * It does two things: 
+         * a) check if the source data is already in cache (based on cache-key that is constructed from the request parameters)
+         * b) if format-parameter provided, invokes the transformation. 
+         * at the end the data to be returned as result is contained in the resultStream
+         * If format is xml, then the data from sourceStream is passed further as resultStream. 
+         *    
+         * @throws Exception  This is handled by struts (is mapped to some result in struts.xml based on the Exception-Class)
+         */
         
         public void prepare() throws Exception {                
@@ -716 +738 @@
                         resultStream = sourceStream;    
                 }else {
+                        MDTransformer transformer = new MDTransformer();
                         // set URL as srcFile (for MDTransformer to pass to xsl-scripts)
-                        MDTransformer transformer = new MDTransformer();
+                        // TODO: WHY??
                         transformer.setSrcFile(getTargetRequest());
-                        // getColumns
-                //      Admin.notifyUser("GPA.getRepository, before xsl:" + getRepository());
                         transformer.setParams(createTransformerParams());
-                        
-                        resultStream = transformer.transformXML(sourceStream);//, getFullFormat(), getColumns(), getStartRecord(), getMaximumRecords(),getLang(),getQ(),String.valueOf(getRepository()));
+                        // here the transformation is invoked
+                        resultStream = transformer.transformXML(sourceStream);
                 }
                         
@@ -730 +751 @@
 
         /**
-         * default Action method
+         * default Action method that gets called by Struts. Everything interesting happens in prepare()
          */
         public String execute() throws Exception {