package liquibase.change.core;

 import liquibase.change.AbstractChange;

 import liquibase.change.ChangeMetaData;

 import liquibase.database.Database;

 import liquibase.database.core.PostgresDatabase;

 import liquibase.statement.DatabaseFunction;

 import liquibase.statement.SqlStatement;

 import liquibase.statement.core.AddAutoIncrementStatement;

 import liquibase.statement.core.AddDefaultValueStatement;

 import liquibase.statement.core.CreateSequenceStatement;

 import liquibase.statement.core.SetNullableStatement;

 import liquibase.util.StringUtils;

 /**

  * Makes an existing column into an auto-increment column. This change is only valid for databases with

  * auto-increment/identity columns. The current version does not support MS-SQL.

  */

 public class AddAutoIncrementChange extends AbstractChange {

     private String schemaName;

     private String tableName;

     private String columnName;

     private String columnDataType;

     public AddAutoIncrementChange() {

         super("addAutoIncrement", "Set Column as Auto-Increment", ChangeMetaData.PRIORITY_DEFAULT);

     }

     public String getSchemaName() {

         return schemaName;

     }

     public void setSchemaName(String schemaName) {

         this.schemaName = StringUtils.trimToNull(schemaName);

     }

     public String getTableName() {

         return tableName;

     }

     public void setTableName(String tableName) {

         this.tableName = tableName;

     }

     public String getColumnName() {

         return columnName;

     }

     public void setColumnName(String columnName) {

         this.columnName = columnName;

     }

     public String getColumnDataType() {

         return columnDataType;

     }

     public void setColumnDataType(String columnDataType) {

         this.columnDataType = columnDataType;

     }

     public SqlStatement[] generateStatements(Database database) {

         if (database instanceof PostgresDatabase) {

             String sequenceName = (getTableName() + "_" + getColumnName() + "_seq").toLowerCase();

             return new SqlStatement[] {

                     new CreateSequenceStatement(schemaName, sequenceName),

                     new SetNullableStatement(schemaName, getTableName(), getColumnName(), null, false),

                     new AddDefaultValueStatement(schemaName, getTableName(), getColumnName(), getColumnDataType(),

                             new DatabaseFunction("NEXTVAL('" + sequenceName + "')")), };

         }

         return new SqlStatement[] { new AddAutoIncrementStatement(getSchemaName(), getTableName(), getColumnName(),

                 getColumnDataType()) };

     }

     public String getConfirmationMessage() {

         return "Auto-increment added to " + getTableName() + "." + getColumnName();

     }

 }