mdb
4747fa8f68
git-svn-id: https://samskivert.googlecode.com/svn/trunk@2132 6335cc39-0255-0410-8fd6-9bcaacd3b74c
84 lines
2.7 KiB
Java
84 lines
2.7 KiB
Java
//
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// $Id$
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//
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// samskivert library - useful routines for java programs
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// Copyright (C) 2006-2007 Michael Bayne, Pär Winzell
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//
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// This library is free software; you can redistribute it and/or modify it
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// under the terms of the GNU Lesser General Public License as published
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// by the Free Software Foundation; either version 2.1 of the License, or
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// (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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package com.samskivert.jdbc.depot.clause;
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import java.sql.PreparedStatement;
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import java.sql.SQLException;
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import java.util.Collection;
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import com.samskivert.io.PersistenceException;
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import com.samskivert.jdbc.depot.QueryBuilderContext;
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import com.samskivert.jdbc.depot.PersistentRecord;
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import com.samskivert.jdbc.depot.expression.ColumnExp;
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import com.samskivert.jdbc.depot.expression.LiteralExp;
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import com.samskivert.jdbc.depot.expression.SQLExpression;
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/**
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* Redirects one field of the persistent object we're creating from its default associated column
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* to a general {@link SQLExpression}.
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*
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* Thus the select portion of a query can include a reference to a different column in a different
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* table through a {@link ColumnExp}, or a literal expression such as COUNT(*) through a
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* {@link LiteralExp}.
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*/
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public class FieldOverride extends QueryClause
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{
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public FieldOverride (String field, String str)
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throws PersistenceException
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{
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this(field, new LiteralExp(str));
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}
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public FieldOverride (String field, Class<? extends PersistentRecord> pClass, String pCol)
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throws PersistenceException
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{
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this(field, new ColumnExp(pClass, pCol));
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}
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public FieldOverride (String field, SQLExpression override)
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throws PersistenceException
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{
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_field = field;
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_override = override;
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}
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/**
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* The field we're overriding. The Query object uses this for indexing.
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*/
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public String getField ()
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{
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return _field;
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}
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// from QueryClause
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public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
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{
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_override.appendExpression(query, builder);
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builder.append(" as ").append(_field);
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}
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/** The name of the field on the persistent object to override. */
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protected String _field;
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/** The overriding expression. */
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protected SQLExpression _override;
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}
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