* Patch from Juerg Lehni: try to autodetect Joins in additionalTables option.

* Some code cleanup:
    - Don't do string concatenation in arguments to StringBuffer.append()
    - Remove redundant if clause
    - Remove throws statement for unthrown exceptions
    - Remove unneeded variable initialzation

src/helma/objectmodel/db/DbMapping.java

@@ -945,11 +945,8 @@ public final class DbMapping {
      * @param rel the Relation we use to select. Currently only used for optimizer hints.
      *            Is null if selecting by primary key.
      * @return the StringBuffer containing the first part of the select query
-     *
-     * @throws SQLException if the table meta data could not be retrieved
-     * @throws ClassNotFoundException if the JDBC driver class was not found
      */
-    public StringBuffer getSelect(Relation rel) throws SQLException, ClassNotFoundException {
+    public StringBuffer getSelect(Relation rel) {
         // assign to local variable first so we are thread safe
         // (selectString may be reset by other threads)
         String sel = selectString;
@@ -985,8 +982,8 @@ public final class DbMapping {
 
         s.append(table);
 
-        if (rel != null && rel.additionalTables != null) {
+        if (rel != null) {
-            s.append(',').append(rel.additionalTables);
+            rel.appendAdditionalTables(s);
         }
 
         s.append(" ");
@@ -1053,7 +1050,7 @@ public final class DbMapping {
                     rel.isReference())) ||
                     name.equalsIgnoreCase(getNameField()) ||
                     name.equalsIgnoreCase(getPrototypeField())) {
-                b1.append(", " + cols[i].getName());
+                b1.append(", ").append(cols[i].getName());
                 b2.append(", ?");
             }
         }

src/helma/objectmodel/db/NodeManager.java

@@ -453,7 +453,7 @@ public final class NodeManager {
 
         if (dbm == null) {
             throw new IllegalArgumentException("DbMapping can't be null in exportNode");
-        } else if ((dbm == null) || !dbm.isRelational()) {
+        } else if (!dbm.isRelational()) {
             throw new IllegalArgumentException("Can't export into non-relational database");
         } else {
             insertRelationalNode(node, dbm, dbm.getConnection());
@@ -901,7 +901,7 @@ public final class NodeManager {
             Statement stmt = null;
 
             try {
-                String q = null;
+                String q;
 
                 StringBuffer b = new StringBuffer("SELECT ");
 
@@ -913,9 +913,7 @@ public final class NodeManager {
                                .append(idfield).append(" FROM ")
                                .append(table);
 
-                if (rel.additionalTables != null) {
+                rel.appendAdditionalTables(b);
-                     b.append(',').append(rel.additionalTables);
-                }
 
                 if (home.getSubnodeRelation() != null) {
                     // subnode relation was explicitly set
@@ -1282,9 +1280,7 @@ public final class NodeManager {
                 String q = null;
                 StringBuffer tables = new StringBuffer(table);
 
-                if (rel.additionalTables != null) {
+                rel.appendAdditionalTables(tables);
-                     tables.append(',').append(rel.additionalTables);
-                }
 
                 // NOTE: we explicitly convert tables StringBuffer to a String
                 // before appending to be compatible with JDK 1.3
@@ -1360,9 +1356,7 @@ public final class NodeManager {
 
             StringBuffer tables = new StringBuffer(table);
 
-            if (rel.additionalTables != null) {
+            rel.appendAdditionalTables(tables);
-                 tables.append(',').append(rel.additionalTables);
-            }
 
             try {
                 // NOTE: we explicitly convert tables StringBuffer to a String

src/helma/objectmodel/db/Relation.java

@@ -92,7 +92,8 @@ public final class Relation {
     String prototype;
     String groupbyPrototype;
     String filter;
-    String additionalTables;
+    private String additionalTables;
+    private boolean additionalTablesJoined = false;
     String queryHints;
     Vector filterFragments;
     Vector filterPropertyRefs;
@@ -115,6 +116,7 @@ public final class Relation {
         this.filterFragments =          rel.filterFragments;
         this.filterPropertyRefs =       rel.filterPropertyRefs;
         this.additionalTables =         rel.additionalTables;
+        this.additionalTablesJoined =   rel.additionalTablesJoined;
         this.queryHints =               rel.queryHints;
         this.maxSize =                  rel.maxSize;
         this.constraints =              rel.constraints;
@@ -290,8 +292,16 @@ public final class Relation {
         // get additional tables
         additionalTables = props.getProperty(propName + ".filter.additionalTables");
 
-        if (additionalTables != null && additionalTables.trim().length() == 0) {
+        if (additionalTables != null) {
+            if (additionalTables.trim().length() == 0) {
                 additionalTables = null;
+            } else {
+                String ucTables = additionalTables.toUpperCase();
+                // see wether the JOIN syntax is used. look for " join " with whitespaces on both sides
+                // and for "join " at the beginning:
+                additionalTablesJoined = (ucTables.indexOf(" JOIN ") != -1 ||
+                        ucTables.startsWith("STRAIGHT_JOIN ") || ucTables.startsWith("JOIN "));
+            }
         }
 
         // get query hints
@@ -787,22 +797,29 @@ public final class Relation {
 
         // add group and order clauses
         if (groupby != null) {
-            q.append(" GROUP BY " + groupby);
+            q.append(" GROUP BY ").append(groupby);
 
             if (useOrder && (groupbyOrder != null)) {
-                q.append(" ORDER BY " + groupbyOrder);
+                q.append(" ORDER BY ").append(groupbyOrder);
             }
         } else if (useOrder && (order != null)) {
-            q.append(" ORDER BY " + order);
+            q.append(" ORDER BY ").append(order);
         }
 
         return q.toString();
     }
 
+    protected void appendAdditionalTables(StringBuffer q) {
+        if (additionalTables != null) {
+            q.append(additionalTablesJoined ? ' ' : ',');
+            q.append(additionalTables);
+        }
+    }
+
     /**
      *  Build the filter.
      */
-    protected void appendFilter(StringBuffer q, INode nonvirtual, String prefix) throws SQLException {
+    protected void appendFilter(StringBuffer q, INode nonvirtual, String prefix) {
         q.append(prefix);
         q.append('(');
         if (filterFragments == null) {
@@ -813,26 +830,6 @@ public final class Relation {
             while (i.hasMoreElements()) {
                 String fragment = (String) i.nextElement();
                 if (fragment == null) {
-                    /*
-                    // begin property version
-                    String propertyName = (String) j.nextElement();
-                    Object value = null;
-                    if (propertyName != null) {
-                        if (propertyName.equals("__id__") || propertyName.equals("_id")) {
-                            value = nonvirtual.getID();
-                        } else if (propertyName.equals("__name__")) {
-                            value = nonvirtual.getName();
-                        } else if (propertyName.equals("__prototype__") || propertyName.equals("_prototype")) {
-                            value = nonvirtual.getPrototype();
-                        } else {
-                            IProperty property = nonvirtual.get(propertyName);
-                            if (property != null) {
-                                value = property.getValue();
-                            }
-                        }
-                    }
-                    // end property version
-                    */
                     // begin column version
                     String columnName = (String) j.nextElement();
                     Object value = null;