* Implement db mapping dependencies introduced by additionalTables switch

* Try to get extract column name from sql functions when converting db column to property
* Added Javadoc comments

src/helma/objectmodel/db/DbMapping.java

@@ -112,6 +112,9 @@ public final class DbMapping {
     // evict objects of this type when received via replication
     private boolean evictOnReplication;
 
+    // Set of mappings that depend on us and should be forwarded last data change events
+    HashSet dependentMappings = new HashSet();
+
     /**
      * Create an empty DbMapping
      */
@@ -140,12 +143,10 @@ public final class DbMapping {
         db2prop = new HashMap();
 
         columnMap = new HashMap();
-
         parentInfo = null;
-
         idField = null;
-
         this.props = props;
+        readBasicProperties();
     }
 
     /**
@@ -155,17 +156,12 @@ public final class DbMapping {
         return props.lastModified() != lastTypeChange;
     }
 
-
     /**
-     * Read the mapping from the Properties. Return true if the properties were changed.
+     * Read in basic properties and register dbmapping with the
-     * The read is split in two, this method and the rewire method. The reason is that in order
+     * dbsource.
-     * for rewire to work, all other db mappings must have been initialized and registered.
      */
-    public synchronized void update() {
+    private void readBasicProperties() {
-        // read in properties
         tableName = props.getProperty("_table");
-        idgen = props.getProperty("_idgen");
-
         dbSourceName = props.getProperty("_db");
 
         if (dbSourceName != null) {
@@ -183,21 +179,33 @@ public final class DbMapping {
 
                 // mark mapping as invalid by nulling the dbSource field
                 dbSource = null;
+            } else {
+                // dbSource and tableName not null - register this instance
+                dbSource.registerDbMapping(this);
+            }
         }
     }
 
+
+
+    /**
+     * Read the mapping from the Properties. Return true if the properties were changed.
+     * The read is split in two, this method and the rewire method. The reason is that in order
+     * for rewire to work, all other db mappings must have been initialized and registered.
+     */
+    public synchronized void update() {
+        // read in properties
+        readBasicProperties();
+        idgen = props.getProperty("_idgen");
         // if id field is null, we assume "ID" as default. We don't set it
         // however, so that if null we check the parent prototype first.
         idField = props.getProperty("_id");
-
         nameField = props.getProperty("_name");
-
         protoField = props.getProperty("_prototype");
+        evictOnReplication = "true".equals(props.getProperty("_evictOnReplication"));
 
         String parentSpec = props.getProperty("_parent");
 
-        evictOnReplication = "true".equals(props.getProperty("_evictOnReplication"));
-
         if (parentSpec != null) {
             // comma-separated list of properties to be used as parent
             StringTokenizer st = new StringTokenizer(parentSpec, ",;");
@@ -503,6 +511,14 @@ public final class DbMapping {
             return null;
         }
 
+        // SEMIHACK: If columnName is a function call, try to extract actual
+        // column name from it
+        int open = columnName.indexOf('(');
+        int close = columnName.indexOf(')');
+        if (open > -1 && close > open) {
+            columnName = columnName.substring(open + 1, close);
+        }
+
         return _columnNameToProperty(columnName.toUpperCase());
     }
 
@@ -1163,9 +1179,9 @@ public final class DbMapping {
     }
 
     /**
+     * Return a string representation for this DbMapping
      *
-     *
+     * @return a string representation
-     * @return ...
      */
     public String toString() {
         if (typename == null) {
@@ -1176,18 +1192,18 @@ public final class DbMapping {
     }
 
     /**
+     * Get the last time something changed in the Mapping
      *
-     *
+     * @return time of last mapping change
-     * @return ...
      */
     public long getLastTypeChange() {
         return lastTypeChange;
     }
 
     /**
+     * Get the last time something changed in our data
      *
-     *
+     * @return time of last data change
-     * @return ...
      */
     public long getLastDataChange() {
         // refer to parent mapping if it uses the same db/table
@@ -1199,25 +1215,48 @@ public final class DbMapping {
     }
 
     /**
-     *
+     * Set the last time something changed in the data, propagating the event
+     * to mappings that depend on us through an additionalTables switch.
      */
     public void setLastDataChange(long t) {
-        // propagate data change timestamp to storage-compatible parent mapping
+        // forward data change timestamp to storage-compatible parent mapping
         if (inheritsStorage()) {
             parentMapping.setLastDataChange(t);
+        } else {
+            lastDataChange = t;
+            // propagate data change timestamp to mappings that depend on us
+            if (!dependentMappings.isEmpty()) {
+                Iterator it = dependentMappings.iterator();
+                while(it.hasNext()) {
+                    DbMapping dbmap = (DbMapping) it.next();
+                    dbmap.setIndirectDataChange(t);
+                }
+            }
+        }
+    }
+
+    /**
+     * Set the last time something changed in the data. This is already an indirect
+     * data change triggered by a mapping we depend on, so we don't propagate it to
+     * mappings that depend on us through an additionalTables switch.
+     */
+    protected void setIndirectDataChange(long t) {
+        // forward data change timestamp to storage-compatible parent mapping
+        if (inheritsStorage()) {
+            parentMapping.setIndirectDataChange(t);
         } else {
             lastDataChange = t;
         }
     }
 
     /**
+     * Helper method to generate a new ID. This is only used in the special case
+     * when using the select(max) method and the underlying table is still empty.
      *
-     *
+     * @param dbmax the maximum value already stored in db
-     * @param dbmax ...
+     * @return a new and hopefully unique id
-     *
-     * @return ...
      */
-    public synchronized long getNewID(long dbmax) {
+    protected synchronized long getNewID(long dbmax) {
         // refer to parent mapping if it uses the same db/table
         if (inheritsStorage()) {
             return parentMapping.getNewID(dbmax);
@@ -1228,9 +1267,9 @@ public final class DbMapping {
     }
 
     /**
+     * Return an enumeration of all properties defined by this db mapping.
      *
-     *
+     * @return the property enumeration
-     * @return ...
      */
     public Enumeration getPropertyEnumeration() {
         HashSet set = new HashSet();
@@ -1250,6 +1289,11 @@ public final class DbMapping {
             };
     }
 
+    /**
+     * Collect a set of all properties defined by this db mapping
+     *
+     * @param basket the set to put properties into
+     */
     private void collectPropertyNames(HashSet basket) {
         // fetch propnames from parent mapping first, than add our own.
         if (parentMapping != null) {
@@ -1282,7 +1326,7 @@ public final class DbMapping {
      *
      * @return true if this mapping shares its parent mapping storage
      */
-    private boolean inheritsStorage() {
+    protected boolean inheritsStorage() {
         // note: tableName and dbSourceName are nulled out in update() if they
         // are inherited from the parent mapping. This way we know that
         // storage is not inherited if either of them is not null.
@@ -1344,20 +1388,30 @@ public final class DbMapping {
     }
 
     /**
+     * Get the mapping we inherit from, or null
      *
-     *
+     * @return the parent DbMapping, or null
-     * @return ...
      */
     public DbMapping getParentMapping() {
         return parentMapping;
     }
 
     /**
+     * Get our ResourceProperties
      *
-     *
+     * @return our properties
-     * @return ...
      */
     public ResourceProperties getProperties() {
         return props;
     }
+
+    /**
+     * Register a DbMapping that depends on this DbMapping, so that collections of other mapping
+     * should be reloaded if data on this mapping is updated.
+     *
+     * @param dbmap the DbMapping that depends on us
+     */
+    protected void addDependency(DbMapping dbmap) {
+        this.dependentMappings.add(dbmap);
+    }
 }

src/helma/objectmodel/db/DbSource.java

@@ -23,6 +23,7 @@ import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.util.Enumeration;
 import java.util.Properties;
+import java.util.Hashtable;
 
 /**
  *  This class describes a releational data source (URL, driver, user and password).
@@ -36,6 +37,7 @@ public class DbSource {
     private String driver;
     private boolean isOracle;
     private long lastRead = 0L;
+    private Hashtable dbmappings = new Hashtable();
 
     /**
      * Creates a new DbSource object.
@@ -143,38 +145,59 @@ public class DbSource {
     }
 
     /**
+     * Return the class name of the JDBC driver
      *
-     *
+     * @return the class name of the JDBC driver
-     * @return ...
      */
     public String getDriverName() {
         return driver;
     }
 
     /**
+     * Return the name of the db dource
      *
-     *
+     * @return the name of the db dource
-     * @return ...
      */
     public String getName() {
         return name;
     }
 
     /**
+     * Set the default (server-wide) properties
      *
-     *
+     * @param props server default db.properties
-     * @param props ...
      */
     public static void setDefaultProps(ResourceProperties props) {
         defaultProps = props;
     }
 
     /**
-     * Is this an Oracle database?
+     * Check if this DbSource represents an Oracle database
      *
      * @return true if we're using an oracle JDBC driver
      */
     public boolean isOracle() {
         return isOracle;
     }
+
+    /**
+     * Register a dbmapping by its table name.
+     *
+     * @param dbmap the DbMapping instance to register
+     */
+    protected void registerDbMapping(DbMapping dbmap) {
+        if (!dbmap.inheritsStorage() && dbmap.getTableName() != null) {
+            dbmappings.put(dbmap.getTableName().toUpperCase(), dbmap);
+        }
+    }
+
+    /**
+     * Look up a DbMapping instance for the given table name.
+     *
+     * @param tablename the table name
+     * @return the matching DbMapping instance
+     */
+    protected DbMapping getDbMapping(String tablename) {
+        return (DbMapping) dbmappings.get(tablename.toUpperCase());
+    }
 }

src/helma/objectmodel/db/Relation.java

@@ -19,6 +19,7 @@ package helma.objectmodel.db;
 import helma.framework.core.Application;
 import helma.objectmodel.INode;
 import helma.objectmodel.IProperty;
+import helma.util.StringUtils;
 
 import java.sql.SQLException;
 import java.util.HashMap;
@@ -297,6 +298,21 @@ public final class Relation {
                 additionalTables = null;
             } else {
                 String ucTables = additionalTables.toUpperCase();
+                // create dependencies implied by additional tables
+                DbSource dbsource = otherType.getDbSource();
+                if (dbsource != null) {
+                    String[] tables = StringUtils.split(ucTables, ", ");
+                    for (int i=0; i<tables.length; i++) {
+                        // Skip some join-related keyworks we might encounter here
+                        if ("AS".equals(tables[i]) || "ON".equals(tables[i])) {
+                            continue;
+                        }
+                        DbMapping dbmap = dbsource.getDbMapping(tables[i]);
+                        if (dbmap != null) {
+                            dbmap.addDependency(otherType);
+                        }
+                    }
+                }
                 // 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 ||