package org.apache.torque.engine.database.model;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License.  You may obtain a copy of the License at

  *

  *   http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing,

  * software distributed under the License is distributed on an

  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

  * KIND, either express or implied.  See the License for the

  * specific language governing permissions and limitations

  * under the License.

  */

 import java.util.List;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.apache.torque.engine.EngineException;

 /**

  * A <code>NameGenerator</code> implementation for table-specific

  * constraints.  Conforms to the maximum column name length for the

  * type of database in use.

  *

  * @author <a href="mailto:dlr@finemaltcoding.com>Daniel Rall</a>

  * @version $Id: ConstraintNameGenerator.java,v 1.1 2007-10-21 07:57:27 abyrne Exp $

  */

 public class ConstraintNameGenerator implements NameGenerator

 {

     /** Logging class from commons.logging */

     private static Log log = LogFactory.getLog(ConstraintNameGenerator.class);

     /**

      * First element of <code>inputs</code> should be of type {@link

      * org.apache.torque.engine.database.model.Database}, second

      * should be a table name, third is the type identifier (spared if

      * trimming is necessary due to database type length constraints),

      * and the fourth is a <code>Integer</code> indicating the number

      * of this contraint.

      *

      * @see org.apache.torque.engine.database.model.NameGenerator

      */

     public String generateName(List inputs)

         throws EngineException

     {

         StringBuffer name = new StringBuffer();

         Database db = (Database) inputs.get(0);

         name.append((String) inputs.get(1));

         String namePostfix = (String) inputs.get(2);

         String constraintNbr = inputs.get(3).toString();

         // Calculate maximum RDBMS-specific column character limit.

         int maxBodyLength = -1;

         try

         {

             int maxColumnNameLength = db.getPlatform().getMaxColumnNameLength();

             maxBodyLength = (maxColumnNameLength - namePostfix.length()

                     - constraintNbr.length() - 2);

             if (log.isDebugEnabled())

             {

                 log.debug("maxColumnNameLength=" + maxColumnNameLength

                         + " maxBodyLength=" + maxBodyLength);

             }

         }

         catch (NumberFormatException maxLengthUnknown)

         {

         }

         // Do any necessary trimming.

         if (maxBodyLength != -1 && name.length() > maxBodyLength)

         {

             name.setLength(maxBodyLength);

         }

         name.append(STD_SEPARATOR_CHAR).append(namePostfix)

             .append(STD_SEPARATOR_CHAR).append(constraintNbr);

         return name.toString();

     }

 }