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();

     }

 }