package liquibase.sqlgenerator.core;

 import liquibase.database.Database;

 import liquibase.database.core.InformixDatabase;

 import liquibase.database.typeconversion.TypeConverterFactory;

 import liquibase.database.core.SybaseDatabase;

 import liquibase.database.structure.Column;

 import liquibase.database.structure.Table;

 import liquibase.exception.ValidationErrors;

 import liquibase.sql.Sql;

 import liquibase.sql.UnparsedSql;

 import liquibase.sqlgenerator.SqlGeneratorChain;

 import liquibase.statement.core.AddDefaultValueStatement;

 public class AddDefaultValueGeneratorInformix extends AddDefaultValueGenerator {

     @Override

     public int getPriority() {

         return PRIORITY_DATABASE;

     }

     @Override

     public boolean supports(AddDefaultValueStatement statement, Database database) {

         return database instanceof InformixDatabase;

     }

     @Override

     public ValidationErrors validate(AddDefaultValueStatement addDefaultValueStatement, Database database,

             SqlGeneratorChain sqlGeneratorChain) {

         ValidationErrors validationErrors = super.validate(addDefaultValueStatement, database, sqlGeneratorChain);

         if (addDefaultValueStatement.getColumnDataType() == null) {

             validationErrors.checkRequiredField("columnDataType", addDefaultValueStatement.getColumnDataType());

         }

         return validationErrors;

     }

     @Override

     public Sql[] generateSql(AddDefaultValueStatement statement, Database database, SqlGeneratorChain sqlGeneratorChain) {

         Column column = new Column().setTable(new Table(statement.getTableName()).setSchema(statement.getSchemaName()))

                 .setName(statement.getColumnName());

         Object defaultValue = statement.getDefaultValue();

         StringBuffer sql = new StringBuffer("ALTER TABLE ");

         sql.append(database.escapeTableName(statement.getSchemaName(), statement.getTableName()));

         sql.append(" MODIFY (");

         sql.append(database.escapeColumnName(statement.getSchemaName(), statement.getTableName(),

                 statement.getColumnName()));

         sql.append(" ");

         sql.append(TypeConverterFactory.getInstance().findTypeConverter(database)

                 .getDataType(statement.getColumnDataType(), false));

         sql.append(" DEFAULT ");

         sql.append(TypeConverterFactory.getInstance().findTypeConverter(database).getDataType(defaultValue)

                 .convertObjectToString(defaultValue, database));

         sql.append(")");

         UnparsedSql unparsedSql = new UnparsedSql(sql.toString(), column);

         return new Sql[] { unparsedSql };

     }

 }