Some refactoring of query generation; addition of "for update" support. From

Zell.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@1961 6335cc39-0255-0410-8fd6-9bcaacd3b74c

src/java/com/samskivert/jdbc/depot/DepotMarshaller.java

@@ -472,7 +472,7 @@ public class DepotMarshaller<T>
             }
             update.append(field).append(" = ?");
         }
-        update.append(" where "); key.appendClause(null, update);
+        key.appendClause(null, update);
 
         try {
             PreparedStatement pstmt = conn.prepareStatement(update.toString());
@@ -513,7 +513,7 @@ public class DepotMarshaller<T>
             }
             update.append(field).append(" = ?");
         }
-        update.append(" where "); key.appendClause(null, update);
+        key.appendClause(null, update);
 
         PreparedStatement pstmt = conn.prepareStatement(update.toString());
         idx = 0;
@@ -533,7 +533,7 @@ public class DepotMarshaller<T>
     public PreparedStatement createDelete (Connection conn, Key key)
         throws SQLException
     {
-        StringBuilder query = new StringBuilder("delete from " + getTableName() + " where ");
+        StringBuilder query = new StringBuilder("delete from " + getTableName());
         key.appendClause(null, query);
         PreparedStatement pstmt = conn.prepareStatement(query.toString());
         key.bindArguments(pstmt, 1);
@@ -557,7 +557,7 @@ public class DepotMarshaller<T>
             update.append(modifiedFields[ii]).append(" = ");
             update.append(modifiedValues[ii]);
         }
-        update.append(" where "); key.appendClause(null, update);
+        key.appendClause(null, update);
 
         PreparedStatement pstmt = conn.prepareStatement(update.toString());
         key.bindArguments(pstmt, 1);

src/java/com/samskivert/jdbc/depot/DepotRepository.java

@@ -58,20 +58,20 @@ public class DepotRepository
     /**
      * Loads the persistent object that matches the specified primary key.
      */
-    protected <T> T load (Class<T> type, Comparable primaryKey)
+    protected <T> T load (Class<T> type, Comparable primaryKey, QueryClause... clauses)
         throws PersistenceException
     {
-        return load(type, _ctx.getMarshaller(type).makePrimaryKey(primaryKey));
+        return load(type, _ctx.getMarshaller(type).makePrimaryKey(primaryKey), clauses);
     }
 
     /**
      * Loads the first persistent object that matches the supplied key.
      */
-    protected <T> T load (Class<T> type, Key key)
+    protected <T> T load (Class<T> type, Key key, QueryClause... clauses)
         throws PersistenceException
     {
         final DepotMarshaller<T> marsh = _ctx.getMarshaller(type);
-        return _ctx.invoke(new Query<T>(_ctx, type, key) {
+        return _ctx.invoke(new Query<T>(_ctx, type, key, clauses) {
             public T invoke (Connection conn) throws SQLException {
                 PreparedStatement stmt = createQuery(conn);
                 try {

src/java/com/samskivert/jdbc/depot/Key.java

@@ -89,6 +89,7 @@ public class Key
 
     public void appendClause (Query query, StringBuilder builder)
     {
+        builder.append(" where ");
         for (int ii = 0; ii < columns.length; ii++) {
             if (ii > 0) {
                 builder.append(" and ");

src/java/com/samskivert/jdbc/depot/Query.java

@@ -33,6 +33,7 @@ import java.util.Set;
 
 import com.samskivert.io.PersistenceException;
 import com.samskivert.jdbc.depot.clause.FieldOverrideClause;
+import com.samskivert.jdbc.depot.clause.ForUpdateClause;
 import com.samskivert.jdbc.depot.clause.GroupByClause;
 import com.samskivert.jdbc.depot.clause.JoinClause;
 import com.samskivert.jdbc.depot.clause.LimitClause;
@@ -130,25 +131,23 @@ public abstract class Query<T>
         query.append("   from " + mainMarshaller.getTableName() + " as T ");
 
         for (JoinClause clause : _joinClauses) {
-            query.append(" inner join " );
             clause.appendClause(this, query);
         }
         if (_key != null) {
-            query.append(" where ");
             _key.appendClause(this, query);
         }
         if (_groupBy != null) {
-            query.append(" group by ");
             _groupBy.appendClause(this, query);
         }
         if (_orderBy != null) {
-            query.append(" order by ");
             _orderBy.appendClause(this, query);
         }
         if (_limit != null) {
-            query.append(" limit ");
             _limit.appendClause(this, query);
         }
+        if (_forUpdate != null) {
+            _forUpdate.appendClause(this, query);
+        }
 
         PreparedStatement pstmt = conn.prepareStatement(query.toString());
         int argIdx = 1;
@@ -164,6 +163,9 @@ public abstract class Query<T>
         if (_limit != null) {
             argIdx = _limit.bindArguments(pstmt, argIdx);
         }
+        if (_forUpdate != null) {
+            argIdx = _forUpdate.bindArguments(pstmt, argIdx);
+        }
 
         return pstmt;
     }
@@ -215,6 +217,13 @@ public abstract class Query<T>
                         "Query can't contain multiple Limit clauses.");
                 }
                 _limit = (LimitClause) clause;
+
+            } else if (clause instanceof ForUpdateClause) {
+                if (_forUpdate != null) {
+                    throw new IllegalArgumentException(
+                        "Query can't contain multiple For Update clauses.");
+                }
+                _forUpdate = (ForUpdateClause) clause;
             }
         }
         _classMap = new HashMap<Class, DepotMarshaller>();
@@ -251,4 +260,7 @@ public abstract class Query<T>
 
     /** The limit clause, if any. */
     protected LimitClause _limit;
+    
+    /** The For Update clause, if any. */
+    protected ForUpdateClause _forUpdate;
 }

src/java/com/samskivert/jdbc/depot/clause/ForUpdateClause.java

@@ -0,0 +1,53 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006 Michael Bayne, Pär Winzell
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot.clause;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.util.Collection;
+
+import com.samskivert.jdbc.depot.Query;
+
+/**
+ *  Represents a FOR UPDATE clause.
+ */
+public class ForUpdateClause
+    implements QueryClause
+{
+    // from QueryClause
+    public Collection<Class> getClassSet ()
+    {
+        return null;
+    }
+
+    // from QueryClause
+    public void appendClause (Query query, StringBuilder builder)
+    {
+        builder.append(" for update ");
+    }
+
+    // from QueryClause
+    public int bindArguments (PreparedStatement pstmt, int argIdx)
+        throws SQLException
+    {
+        return argIdx;
+    }
+}

src/java/com/samskivert/jdbc/depot/clause/GroupByClause.java

@@ -48,6 +48,7 @@ public class GroupByClause
     // from QueryClause
     public void appendClause (Query query, StringBuilder builder)
     {
+        builder.append(" group by ");
         for (int ii = 0; ii < _values.length; ii++) {
             if (ii > 0) {
                 builder.append(", ");

src/java/com/samskivert/jdbc/depot/clause/JoinClause.java

@@ -51,6 +51,7 @@ public class JoinClause
     // from QueryClause
     public void appendClause (Query query, StringBuilder builder)
     {
+        builder.append(" inner join " );
         String jAbbrev = query.getTableAbbreviation(_joinClass);
         builder.append(query.getTableName(_joinClass) + " as " + jAbbrev + " on T." +
                        _primaryColumn + " = " + jAbbrev + "." + _joinColumn);

src/java/com/samskivert/jdbc/depot/clause/LimitClause.java

@@ -48,7 +48,7 @@ public class LimitClause
     // from QueryClause
     public void appendClause (Query query, StringBuilder builder)
     {
-        builder.append("? offset ?");
+        builder.append(" limit ? offset ? ");
     }
 
     // from QueryClause

src/java/com/samskivert/jdbc/depot/clause/OrderByClause.java

@@ -48,6 +48,7 @@ public class OrderByClause
     // from QueryClause
     public void appendClause (Query query, StringBuilder builder)
     {
+        builder.append(" order by ");
         for (int ii = 0; ii < _values.length; ii++) {
             if (ii > 0) {
                 builder.append(", ");