/* // $Id: //guest/julian_hyde/saffron/src/main/saffron/rel/convert/ConverterRule.java#1 $ // Saffron preprocessor and data engine // Copyright (C) 2002 Julian Hyde <julian.hyde@mail.com> // // This library is free software; you can redistribute it and/or // modify it under the terms of the GNU Library General Public // License as published by the Free Software Foundation; either // version 2 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 // Library General Public License for more details. // // You should have received a copy of the GNU Library 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. // // See the COPYING file located in the top-level-directory of // the archive of this library for complete text of license. */ package saffron.rel.convert; import openjava.mop.Environment; import saffron.opt.Operand; import saffron.opt.SingleConventionRule; import saffron.rel.Rel; import saffron.util.Util; /** * Generic rule to translate a {@link saffron.rel.Rel} whose class is * <code>clazz</code> into an equivalent expression with * <code>convention</code> calling convention. **/ public class ConverterRule extends SingleConventionRule { Class clazz; public ConverterRule(int convention, Class clazz) { super( new Operand(clazz, null), convention); this.clazz = clazz; } public Rel apply(Environment env, Rel[] rels) { Rel rel = rels[0]; Class actualClass = rel.getClass(); // Rel must be a sub-type of clazz otherwise the rule would not // have matched. Util.assert(clazz.isAssignableFrom(actualClass)); if (clazz != actualClass) { // Sub-types are not good enough. We can translate a Filter to // an JavaFilter, but if we translate an JavaFilter into a // JavaFilter, we get a cycle. return null; } return rel.changeConvention(planner, convention); } }
# | Change | User | Description | Committed | |
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#2 | 1801 | Julian Hyde |
saffron: add ObjectSchema; rules can now be matched more than once; started to implement correlations in queries in from list. |
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#1 | 1467 | Julian Hyde |
saffron: First saffron check-in; incorporate my changes to openjava. |