introduce a signalling exception and improve error messages

darcs-hash:20041124220047-2eb37-3e02150c6258dcc816ca174af821f1b46c093bc2.gz

diff --git a/src/java/org/ibex/xt/JSElement.java b/src/java/org/ibex/xt/JSElement.java
index cfa1a1f..c6eee6e 100644 (file)
--- a/src/java/org/ibex/xt/JSElement.java
+++ b/src/java/org/ibex/xt/JSElement.java
@@ -9,6 +9,7 @@ import java.util.*;
 import org.ibex.util.*;
 import org.ibex.js.JS;
 import org.ibex.js.JSScope;
+import org.ibex.js.JSExn;
 
 public class JSElement extends JSScope implements XML.Element {
     protected XML.Element wrapped;
@@ -42,7 +43,7 @@ public class JSElement extends JSScope implements XML.Element {
                 declare(a.getKey(i));
                 put(a.getKey(i), eval(a.getVal(i)));
             }
-        } catch (Exception e) { throw new RuntimeException(e); }
+        } catch (JSExn e) { throw new Exn(e); }
     }
 
     private Object eval(String s) {
@@ -58,9 +59,9 @@ public class JSElement extends JSScope implements XML.Element {
                   app instanceof String ||
                   app instanceof Number ||
                   app instanceof Boolean))
-                throw new RuntimeException("javascripts within ${...} can only return " +
-                                           "strings, numbers, and booleans; not a " +
-                                           app.getClass().getName());
+                throw new Exn("javascripts within ${...} can only return " +
+                              "strings, numbers, and booleans; not a " +
+                              app.getClass().getName());
 
             ret.append(app == null ? "null" : app.toString());
         }
@@ -72,9 +73,11 @@ public class JSElement extends JSScope implements XML.Element {
         try {
             return JS.eval(JS.cloneWithNewParentScope(
                            JS.fromReader("input", 0, new StringReader(s)), this));
-        } catch (Exception e) {
+        } catch (IOException e) {
             e.printStackTrace();
-            throw new RuntimeException(e);
+            throw new Exn("impossible IOException, reading from StringReader");
+        } catch (JSExn e) {
+            throw new Exn(e);
         }
     }
 
@@ -147,4 +150,10 @@ public class JSElement extends JSScope implements XML.Element {
             return i >= a.attrSize() ? b.getUri(i-a.attrSize()) : a.getUri(i); }
         public int attrSize() { return a.attrSize() + b.attrSize(); }
     }
+
+    public static class Exn extends RuntimeException {
+        public Exn(String cause) { super(cause); }
+        public Exn(JSExn e) { super(e); }
+        public String toString() { return "JSElement.Exn: "+getMessage(); }
+    }
 }

diff --git a/src/java/org/ibex/xt/Servlet.java b/src/java/org/ibex/xt/Servlet.java
index 7402dd2..53eb197 100644 (file)
--- a/src/java/org/ibex/xt/Servlet.java
+++ b/src/java/org/ibex/xt/Servlet.java
@@ -13,7 +13,6 @@ import org.prevayler.*;
 
 public class Servlet extends HttpServlet {
 
-    private String path;
     private Prevayler prevayler;
     private JS prevalent;
     private ServletContext cx = null;
@@ -35,12 +34,30 @@ public class Servlet extends HttpServlet {
 
     public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException { doGet(request, response); }
     public void doGet(HttpServletRequest rq, HttpServletResponse rs) throws IOException {
-        String path = cx.getRealPath(rq.getServletPath());
+        String src = rq.getServletPath();
         Servlet.Scope scope = new Servlet.Scope(cx, rq, rs, prevayler);
-        rs.getWriter().write("beginning output...");
-        try { Template.wrap(Template.parse(path, scope), scope).out(rs.getWriter()); }
-        catch (Exception e) { e.printStackTrace(); System.out.println("e = "+e); }
-        rs.getWriter().write("...output ends.");
+        try {
+            while (src != null) {
+                try {
+                    StringWriter w = new StringWriter();
+                    Template t = Template.parse(cx.getRealPath(src), scope);
+                    Template.wrap(t, scope).out(w);
+                    rs.getWriter().write(w.toString());
+                    src = null;
+                } catch (Template.RedirectSignal r) {
+                    src = r.getTarget();
+                }
+            }
+        } catch (Template.Signal s) {
+        } catch (JSElement.Exn e) {
+            PrintWriter w = new PrintWriter(rs.getWriter());
+            w.print("\n"+src+": ");
+            w.println(e.getMessage());
+            System.out.println(e);
+        } catch (Exception e) {
+            System.out.println("Unexpected Exception:");
+            e.printStackTrace();
+        }
     }
 
     public static class Scope extends Template.Scope {

diff --git a/src/java/org/ibex/xt/Template.java b/src/java/org/ibex/xt/Template.java
index 445a6ee..8456f61 100644 (file)
--- a/src/java/org/ibex/xt/Template.java
+++ b/src/java/org/ibex/xt/Template.java
@@ -36,7 +36,7 @@ public class Template extends JSElement {
             //#switch(uri.substring(19))
             case "io": System.out.println("ibex.xt.io not yet implemented"); // TODO
             //#end
-            //throw new RuntimeException("Unknown XT library: "+uri);
+            //throw new JSElement.Exn("Unknown XT library: "+uri);
 
         } else if (uri.startsWith("local:")) {
             Template t = parse(s.getLocalPath() + uri.substring(6), s);
@@ -45,7 +45,7 @@ public class Template extends JSElement {
             if (c.size() > 0) {
                 // move all children from e to placeholder
                 XML.Element placeholder = findPlaceholder(t);
-                if (placeholder == null) throw new RuntimeException(
+                if (placeholder == null) throw new JSElement.Exn(
                     "<"+e.getQName()+"> attempted to include children into a " +
                     "template which does not contain an <xt:children /> tag.");
 
@@ -102,7 +102,7 @@ public class Template extends JSElement {
             try {
                 Object varIf = get("if"); if (varIf != null) undeclare("if");
                 if (varIf != null && !"true".equals(varIf)) return;
-            } catch (JSExn e) { throw new RuntimeException(e); }
+            } catch (JSExn e) { throw new JSElement.Exn(e); }
 
             wrapped.out(w);
         }
@@ -113,7 +113,7 @@ public class Template extends JSElement {
             super(e);
             List c = getChildren();
             for (int i=0; i < c.size(); i++)
-                if (c.get(i) instanceof XML.Element) throw new RuntimeException(
+                if (c.get(i) instanceof XML.Element) throw new JSElement.Exn(
                     "<"+getPrefix()+":js> tags may not have child elements");
         }
 
@@ -138,16 +138,16 @@ public class Template extends JSElement {
                 Object varPut = get("put"); if (varPut != null) undeclare("put");
 
                 varIn = exec("return (" + varIn + ");");
-                if (varIn == null || (varIn instanceof JSArray)) throw new RuntimeException(
+                if (varIn == null || (varIn instanceof JSArray)) throw new JSElement.Exn(
                     "<"+getPrefix()+":foreach> requires attribute 'in' to specify " +
                     "the name of a valid js array in the current scope, not in='"+varIn+"'.");
 
                 if (varPut == null) varPut = "x";
                 else if (!(varPut instanceof String) || get(varPut) != null)
-                    throw new RuntimeException(
+                    throw new JSElement.Exn(
                     "<"+getPrefix()+":foreach> 'put' attribute requires the name of "+
                     "an undeclared variable, not put='"+varPut+"'.");
-                if (get(varPut) != null) throw new RuntimeException(
+                if (get(varPut) != null) throw new JSElement.Exn(
                     "<"+getPrefix()+":foreach> has no 'put' attribute defined and the "+
                     "default variable 'x' already exists in the current scope.");
 
@@ -158,7 +158,7 @@ public class Template extends JSElement {
                     put(varPut, it.next());
                     for (int i=0; i < c.size(); i++) ((Tree.Leaf)c.get(i)).out(w);
                 }
-            } catch (JSExn e) { throw new RuntimeException(e); }
+            } catch (JSExn e) { throw new JSElement.Exn(e); }
         }
     }
 
@@ -184,11 +184,6 @@ public class Template extends JSElement {
         }
     }
 
-    public static final class Java extends JSElement {
-        // TODO what exactly?
-        public Java(XML.Element w) { super(w); }
-    }
-
     public abstract static class Scope extends JSScope {
         public Scope(JSScope j) { super(j); }
 
@@ -199,4 +194,11 @@ public class Template extends JSElement {
         public abstract void transaction(JS t);
     }
 
+    public static class Signal extends RuntimeException {}
+    public static class ReturnSignal extends Signal { }
+    public static class RedirectSignal extends Signal {
+        protected String target;
+        public RedirectSignal(String target) { super(); this.target = target; }
+        public String getTarget() { return target; }
+    }
 }