From c0be9ea48d9fea344148d74639e2e5f7923dea0e Mon Sep 17 00:00:00 2001
From: mdb <mdb@6335cc39-0255-0410-8fd6-9bcaacd3b74c>
Date: Thu, 1 Mar 2001 21:06:22 +0000
Subject: [PATCH] Various enhancements to our webmacro extensions.

git-svn-id: https://samskivert.googlecode.com/svn/trunk@60 6335cc39-0255-0410-8fd6-9bcaacd3b74c
---
 .../samskivert/webmacro/ContextPopulator.java |  30 ----
 .../webmacro/DispatcherServlet.java           | 162 +++++++++++++-----
 .../com/samskivert/webmacro/DummyLogic.java   |  19 ++
 .../samskivert/webmacro/DummyPopulator.java   |  19 --
 .../com/samskivert/webmacro/FormUtil.java     |  90 +++++++++-
 .../src/java/com/samskivert/webmacro/Log.java |   8 +-
 .../java/com/samskivert/webmacro/Logic.java   |  30 ++++
 .../src/java/com/samskivert/webmacro/Makefile |   6 +-
 8 files changed, 265 insertions(+), 99 deletions(-)
 delete mode 100644 projects/samskivert/src/java/com/samskivert/webmacro/ContextPopulator.java
 create mode 100644 projects/samskivert/src/java/com/samskivert/webmacro/DummyLogic.java
 delete mode 100644 projects/samskivert/src/java/com/samskivert/webmacro/DummyPopulator.java
 create mode 100644 projects/samskivert/src/java/com/samskivert/webmacro/Logic.java

diff --git a/projects/samskivert/src/java/com/samskivert/webmacro/ContextPopulator.java b/projects/samskivert/src/java/com/samskivert/webmacro/ContextPopulator.java
deleted file mode 100644
index 9e4e7845..00000000
--- a/projects/samskivert/src/java/com/samskivert/webmacro/ContextPopulator.java
+++ /dev/null
@@ -1,30 +0,0 @@
-//
-// $Id: ContextPopulator.java,v 1.1 2001/02/15 01:44:34 mdb Exp $
-
-package com.samskivert.webmacro;
-
-import org.webmacro.servlet.WebContext;
-
-/**
- * The context populator is called upon to populate the WebMacro web
- * context, prior to invoking a particular WebMacro template upon it to
- * generate a response page. The populator takes the place of the servlet
- * in the standard WebMacro architecture and should perform all of the
- * logic involved in handling a particular request.
- *
- * @see DispatcherServlet
- */
-public interface ContextPopulator
-{
-    /**
-     * Perform any necessary computation and populate the context with
-     * data for this request. Any exceptions that are thrown will be
-     * converted into friendly error messages using the exception mapping
-     * services.
-     *
-     * @param context The WebMacro context in scope for this request.
-     *
-     * @see ExceptionMap
-     */
-    public void populate (WebContext context) throws Exception;
-}
diff --git a/projects/samskivert/src/java/com/samskivert/webmacro/DispatcherServlet.java b/projects/samskivert/src/java/com/samskivert/webmacro/DispatcherServlet.java
index 8b10de7d..9264cf29 100644
--- a/projects/samskivert/src/java/com/samskivert/webmacro/DispatcherServlet.java
+++ b/projects/samskivert/src/java/com/samskivert/webmacro/DispatcherServlet.java
@@ -1,5 +1,5 @@
 //
-// $Id: DispatcherServlet.java,v 1.2 2001/02/16 03:27:54 mdb Exp $
+// $Id: DispatcherServlet.java,v 1.3 2001/03/01 21:06:22 mdb Exp $
 
 package com.samskivert.webmacro;
 
@@ -9,7 +9,11 @@ import java.util.HashMap;
 import java.util.Properties;
 import java.util.StringTokenizer;
 
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+
 import javax.servlet.ServletConfig;
+import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
 
 import com.samskivert.util.ConfigUtil;
@@ -22,12 +26,12 @@ import org.webmacro.servlet.*;
  * in the following ways:
  *
  * <ul>
- * <li> It defines the notion of a context populator which populates the
- * context with data to be used to satisfy a particular request. The
- * context populator is not a servlet and is therefore limited in what it
- * can do while populating data. Experience dictates that ultimate
- * flexibility leads to bad design decisions and that this is a place
- * where that sort of thing can be comfortably nipped in the bud. <br><br>
+ * <li> It defines the notion of a logic object which populates the
+ * context with data to be used to satisfy a particular request. The logic
+ * is not a servlet and is therefore limited in what it can do while
+ * populating data. Experience dictates that ultimate flexibility leads to
+ * bad design decisions and that this is a place where that sort of thing
+ * can be comfortably nipped in the bud. <br><br>
  *
  * <li> It allows .wm files to be referenced directly in the URL while
  * maintaining the ability to choose a cobranded template based. The URI
@@ -60,7 +64,7 @@ import org.webmacro.servlet.*;
  * <pre>
  * applications=whowhere
  * whowhere.base_uri=/whowhere
- * whowhere.base_pkg=whowhere.servlets
+ * whowhere.base_pkg=whowhere.logic
  * </pre>
  *
  * This defines an application identified as <code>whowhere</code>. An
@@ -69,10 +73,10 @@ import org.webmacro.servlet.*;
  * <code>base_uri</code> defines the prefix shared by all pages served by
  * the application and which serves to identify which application to
  * invoke when processing a request. The <code>base_pkg</code> is used to
- * construct the populator classname based on the URI and the
+ * construct the logic classname based on the URI and the
  * <code>base_uri</code> parameter.
  *
- * <p> Now let's look at a sample request to determine how the populator
+ * <p> Now let's look at a sample request to determine how the logic
  * classname is resolved. Consider the following request URI:
  *
  * <pre>
@@ -102,16 +106,16 @@ import org.webmacro.servlet.*;
  *
  * <p><b>Error handling</b><br>
  * The dispatcher servlet provides a common error handling mechanism. The
- * design is to catch any exceptions thrown by the populator and to
- * convert them into friendly error messages that are inserted into the
- * web context with the key <code>"error"</code> for easy display in the
+ * design is to catch any exceptions thrown by the logic and to convert
+ * them into friendly error messages that are inserted into the web
+ * context with the key <code>"error"</code> for easy display in the
  * resulting web page.
  *
  * <p> The process of mapping exceptions to friendly error messages is
  * done using the <code>ExceptionMap</code> class. Consult its
  * documentation for an explanation of how it works.
  *
- * @see ContextPopulator
+ * @see Logic
  * @see ExceptionMap
  */
 public class DispatcherServlet extends WMServlet
@@ -148,6 +152,7 @@ public class DispatcherServlet extends WMServlet
 		String appid = tok.nextToken();
 		String baseURI = props.getProperty(appid + ".base_uri");
 		String basePkg = props.getProperty(appid + ".base_pkg");
+		String appcl = props.getProperty(appid + ".application");
 
 		// make sure we're not missing anything
 		if (baseURI == null) {
@@ -161,8 +166,14 @@ public class DispatcherServlet extends WMServlet
 		    continue;
 		}
 
+		Application app = new Application(baseURI, basePkg);
+		// if an application class was specified, initialize it
+		if (appcl != null) {
+		    app.init(appcl, getServletContext());
+		}
+
 		// construct an application object and add it to our list
-		_apps.add(new Application(baseURI, basePkg));
+		_apps.add(app);
 	    }
 	}
     }
@@ -177,19 +188,18 @@ public class DispatcherServlet extends WMServlet
 	    throw new HandlerException("Unable to load template: " + e);
 	}
 
-	// assume an HTML response unless otherwise massaged by the data
-	// populator
+	// assume an HTML response unless otherwise massaged by the logic
 	ctx.getResponse().setContentType("text/html");
 
 	// then we populate the context with data
 	try {
-	    ContextPopulator pop = selectPopulator(ctx);
-	    // if no populator is matched, we simply execute the template
+	    Logic logic = selectLogic(ctx);
+	    // if no logic is matched, we simply execute the template
 	    // directly with the default information in the context (tools
 	    // and other WebMacro services can be used by the template to
 	    // do their WebMacro thing)
-	    if (pop != null) {
-		pop.populate(ctx);
+	    if (logic != null) {
+		logic.invoke(ctx);
 	    }
 	    
 	} catch (DataValidationException dve) {
@@ -197,6 +207,7 @@ public class DispatcherServlet extends WMServlet
 
 	} catch (Exception e) {
 	    ctx.put(ERROR_KEY, ExceptionMap.getMessage(e));
+	    Log.logStackTrace(e);
 	}
 
 	return tmpl;
@@ -222,57 +233,57 @@ public class DispatcherServlet extends WMServlet
     }
 
     /**
-     * This method is called to select the appropriate context populator
-     * for this request. The dispatcher configuration described in this
-     * class's documentation is consulted to map the URI to a populator
-     * class which is then instantiated and a single instance used to
-     * process all matching requests.
+     * This method is called to select the appropriate logic for this
+     * request. The dispatcher configuration described in this class's
+     * documentation is consulted to map the URI to a logic class which is
+     * then instantiated and a single instance used to process all
+     * matching requests.
      *
      * @param ctx The context of this request.
      *
-     * @return The populator to be used in generating the response or null
-     * if no populator could be matched.
+     * @return The logic to be used in generating the response or null if
+     * no logic could be matched.
      */
-    protected ContextPopulator selectPopulator (WebContext ctx)
+    protected Logic selectLogic (WebContext ctx)
     {
 	String path = cleanupURI(ctx.getRequest().getRequestURI());
-	String pclass = null;
-	// Log.info("Loading populator [path=" + path + "].");
+	String lclass = null;
+	// Log.info("Loading logic [path=" + path + "].");
 
 	// try to locate an application that matches this URI
 	for (int i = 0; i < _apps.size(); i++) {
 	    Application app = (Application)_apps.get(i);
 	    if (app.matches(path)) {
-		pclass = app.generateClass(path);
+		lclass = app.generateClass(path);
 		break;
 	    }
 	}
 
 	// if we didn't find a matching application, we can stop now
-	if (pclass == null) {
+	if (lclass == null) {
 	    return null;
 	}
 
-	// otherwise look for a cached populator instance
-	ContextPopulator pop = (ContextPopulator)_pops.get(pclass);
-	if (pop == null) {
+	// otherwise look for a cached logic instance
+	Logic logic = (Logic)_logic.get(lclass);
+	if (logic == null) {
 	    try {
-		Class pcl = Class.forName(pclass);
-		pop = (ContextPopulator)pcl.newInstance();
+		Class pcl = Class.forName(lclass);
+		logic = (Logic)pcl.newInstance();
 
 	    } catch (Throwable t) {
-		Log.warning("Unable to instantiate populator for " +
+		Log.warning("Unable to instantiate logic for " +
 			    "matching application [path=" + path +
-			    ", pclass=" + pclass + ", error=" + t + "].");
+			    ", lclass=" + lclass + ", error=" + t + "].");
 		// use a dummy in it's place so that we don't sit around
 		// all day freaking out about our inability to instantiate
-		// the proper populator class
-		pop = new DummyPopulator();
+		// the proper logic class
+		logic = new DummyLogic();
 	    }
-	    _pops.put(pclass, pop);
+	    _logic.put(lclass, logic);
 	}
 
-	return pop;
+	return logic;
     }
 
     /**
@@ -343,12 +354,73 @@ public class DispatcherServlet extends WMServlet
 	    return _basePkg + uri;
 	}
 
+	public void init (String appclass, ServletContext context)
+	{
+	    // keep track of this for later
+	    _appclass = appclass;
+
+	    try {
+		// get the application class
+		Class appcl = Class.forName(appclass);
+
+		// look up the init method
+		Class[] ptypes = new Class[] { ServletContext.class };
+		Method initmeth = appcl.getDeclaredMethod("init", ptypes);
+
+		// make sure it's static
+		if ((initmeth.getModifiers() & Modifier.STATIC) == 0) {
+		    Log.warning("Application init() method not static " +
+				"[app=" + appclass + "].");
+		    return;
+		}
+
+		// look  up the shutdown method
+		_shutdownMethod =
+		    appcl.getDeclaredMethod("shutdown", new Class[0]);
+
+		// make sure it's static
+		if ((_shutdownMethod.getModifiers() & Modifier.STATIC) == 0) {
+		    Log.warning("Application shutdown() method not static " +
+				"[app=" + appclass + "].");
+		    return;
+		}
+
+		// invoke the init method
+		Object[] args = new Object[] { context };
+		initmeth.invoke(null, args);
+
+	    } catch (NoSuchMethodError nsme) {
+		Log.warning("Application class missing init() method " +
+			    "[app=" + appclass + "].");
+
+	    } catch (Throwable t) {
+		Log.warning("Error initializing application [app=" + appclass +
+			    ", error=" + t + "].");
+	    }
+	}
+
+	public void shutdown ()
+	{
+	    if (_shutdownMethod != null) {
+		try {
+		    _shutdownMethod.invoke(null, null);
+		} catch (Throwable t) {
+		    Log.warning("Error shutting down application " +
+				"[app=" + _appclass + ", error=" + t + "].");
+		    Log.logStackTrace(t);
+		}
+	    }
+	}
+
 	protected String _baseURI;
 	protected String _basePkg;
+
+	protected String _appclass;
+	protected Method _shutdownMethod;
     }
 
     protected ArrayList _apps = new ArrayList();
-    protected HashMap _pops = new HashMap();
+    protected HashMap _logic = new HashMap();
 
     /** This is the key used in the context for error messages. */
     protected static final String ERROR_KEY = "error";
diff --git a/projects/samskivert/src/java/com/samskivert/webmacro/DummyLogic.java b/projects/samskivert/src/java/com/samskivert/webmacro/DummyLogic.java
new file mode 100644
index 00000000..9389b6ec
--- /dev/null
+++ b/projects/samskivert/src/java/com/samskivert/webmacro/DummyLogic.java
@@ -0,0 +1,19 @@
+//
+// $Id: DummyLogic.java,v 1.1 2001/03/01 21:06:22 mdb Exp $
+
+package com.samskivert.webmacro;
+
+import org.webmacro.servlet.WebContext;
+
+/**
+ * The dummy logic is used as a placeholder for URIs that match no normal
+ * logic or for which the matching logic could not be instantiated. It
+ * does nothing.
+ */
+public class DummyLogic implements Logic
+{
+    public void invoke (WebContext context) throws Exception
+    {
+	// we're such a dummy that we do absolutely nothing.
+    }
+}
diff --git a/projects/samskivert/src/java/com/samskivert/webmacro/DummyPopulator.java b/projects/samskivert/src/java/com/samskivert/webmacro/DummyPopulator.java
deleted file mode 100644
index 8fcf555a..00000000
--- a/projects/samskivert/src/java/com/samskivert/webmacro/DummyPopulator.java
+++ /dev/null
@@ -1,19 +0,0 @@
-//
-// $Id: DummyPopulator.java,v 1.1 2001/02/15 01:44:34 mdb Exp $
-
-package com.samskivert.webmacro;
-
-import org.webmacro.servlet.WebContext;
-
-/**
- * The dummy populator is used as a placeholder for URIs that match no
- * normal populator or for which the matching populator could not be
- * instantiated. It does nothing.
- */
-public class DummyPopulator implements ContextPopulator
-{
-    public void populate (WebContext context) throws Exception
-    {
-	// we're such a dummy that we do absolutely nothing.
-    }
-}
diff --git a/projects/samskivert/src/java/com/samskivert/webmacro/FormUtil.java b/projects/samskivert/src/java/com/samskivert/webmacro/FormUtil.java
index d9ef799f..93884fef 100644
--- a/projects/samskivert/src/java/com/samskivert/webmacro/FormUtil.java
+++ b/projects/samskivert/src/java/com/samskivert/webmacro/FormUtil.java
@@ -1,8 +1,13 @@
 //
-// $Id: FormUtil.java,v 1.1 2001/02/15 01:44:34 mdb Exp $
+// $Id: FormUtil.java,v 1.2 2001/03/01 21:06:22 mdb Exp $
 
 package com.samskivert.webmacro;
 
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
+import com.samskivert.util.StringUtil;
 import org.webmacro.servlet.WebContext;
 
 /**
@@ -28,4 +33,87 @@ public class FormUtil
 	    throw new DataValidationException(invalidDataMessage);
 	}
     }
+
+    /**
+     * Fetches the supplied parameter from the request. If the parameter
+     * does not exist, a data validation exception is thrown with the
+     * supplied message.
+     */
+    public static String requireParameter (WebContext context, String name,
+					   String missingDataMessage)
+	throws DataValidationException
+    {
+	String value = context.getForm(name);
+	if (StringUtil.blank(value)) {
+	    throw new DataValidationException(missingDataMessage);
+	}
+	return value;
+    }
+
+    /**
+     * Fetches the supplied parameter from the request and converts it to
+     * a date. The value of the parameter should be a date formatted like
+     * so: 2001-12-25. If the parameter does not exist or is not a
+     * well-formed date, a data validation exception is thrown with the
+     * supplied message.
+     */
+    public static Date requireDateParameter (WebContext context, String name,
+					     String invalidDataMessage)
+	throws DataValidationException
+    {
+	String value = context.getForm(name);
+	Date date = null;
+
+	try {
+	    if (value != null) {
+		date = _dparser.parse(value);
+	    }
+	} catch (ParseException pe) {
+	    // fall through with date == null
+	    Log.info("Date parsing failed: " + pe);
+	}
+
+	// freak out if we failed to parse the date for some reason
+	if (date == null) {
+	    throw new DataValidationException(invalidDataMessage);
+	}
+
+	return date;
+    }
+
+    /**
+     * Returns true if the specified parameter is set in the request
+     * context.
+     *
+     * @return true if the specified parameter is set in the request
+     * context, false otherwise.
+     */
+    public static boolean isSet (WebContext context, String name)
+    {
+	return !StringUtil.blank(context.getForm(name));
+    }
+
+    /**
+     * Returns true if the specified parameter is equal to the supplied
+     * value. If the parameter is not set in the request context, false is
+     * returned.
+     *
+     * @param context The request context.
+     * @param name The parameter whose value should be compared with the
+     * supplied value.
+     * @param value The value to which the parameter may be equal. This
+     * should not be null.
+     *
+     * @return true if the specified parameter is equal to the supplied
+     * parameter, false otherwise.
+     */
+    public static boolean equals (WebContext context, String name,
+				  String value)
+    {
+	return value.equals(context.getForm(name));
+    }
+
+    /** We use this to parse dates in requireDateParameter(). */
+    protected static SimpleDateFormat _dparser =
+	new SimpleDateFormat("yyyy-MM-dd");
 }
diff --git a/projects/samskivert/src/java/com/samskivert/webmacro/Log.java b/projects/samskivert/src/java/com/samskivert/webmacro/Log.java
index 6aca94b3..eed018a1 100644
--- a/projects/samskivert/src/java/com/samskivert/webmacro/Log.java
+++ b/projects/samskivert/src/java/com/samskivert/webmacro/Log.java
@@ -1,5 +1,5 @@
 //
-// $Id: Log.java,v 1.2 2001/02/16 03:27:54 mdb Exp $
+// $Id: Log.java,v 1.3 2001/03/01 21:06:22 mdb Exp $
 
 package com.samskivert.webmacro;
 
@@ -29,4 +29,10 @@ public class Log
     {
 	log.warning(message);
     }
+
+    /** Convenience function. */
+    public static void logStackTrace (Throwable t)
+    {
+	log.logStackTrace(com.samskivert.util.Log.WARNING, t);
+    }
 }
diff --git a/projects/samskivert/src/java/com/samskivert/webmacro/Logic.java b/projects/samskivert/src/java/com/samskivert/webmacro/Logic.java
new file mode 100644
index 00000000..28a0c74f
--- /dev/null
+++ b/projects/samskivert/src/java/com/samskivert/webmacro/Logic.java
@@ -0,0 +1,30 @@
+//
+// $Id: Logic.java,v 1.1 2001/03/01 21:06:22 mdb Exp $
+
+package com.samskivert.webmacro;
+
+import org.webmacro.servlet.WebContext;
+
+/**
+ * The logic class is called upon to populate the WebMacro web context,
+ * prior to invoking a particular WebMacro template upon it to generate a
+ * response page. The logic takes the place of the servlet in the standard
+ * WebMacro architecture and should perform all of the logic involved in
+ * handling a particular request.
+ *
+ * @see DispatcherServlet
+ */
+public interface Logic
+{
+    /**
+     * Perform any necessary computation and populate the context with
+     * data for this request. Any exceptions that are thrown will be
+     * converted into friendly error messages using the exception mapping
+     * services.
+     *
+     * @param context The WebMacro context in scope for this request.
+     *
+     * @see ExceptionMap
+     */
+    public void invoke (WebContext context) throws Exception;
+}
diff --git a/projects/samskivert/src/java/com/samskivert/webmacro/Makefile b/projects/samskivert/src/java/com/samskivert/webmacro/Makefile
index 7a6bc4a6..5b81698d 100644
--- a/projects/samskivert/src/java/com/samskivert/webmacro/Makefile
+++ b/projects/samskivert/src/java/com/samskivert/webmacro/Makefile
@@ -1,16 +1,16 @@
 #
-# $Id: Makefile,v 1.3 2001/02/15 01:44:34 mdb Exp $
+# $Id: Makefile,v 1.4 2001/03/01 21:06:22 mdb Exp $
 
 ROOT = ../../..
 
 SRCS = \
-	ContextPopulator.java \
 	DataValidationException.java \
 	DispatcherServlet.java \
-	DummyPopulator.java \
+	DummyLogic.java \
 	ExceptionMap.java \
 	FormUtil.java \
 	FriendlyException.java \
 	Log.java \
+	Logic.java \
 
 include $(ROOT)/build/Makefile.java