package liquibase.sqlgenerator.core;

 import liquibase.database.Database;

 import liquibase.database.typeconversion.TypeConverterFactory;

 import liquibase.exception.ValidationErrors;

 import liquibase.sql.Sql;

 import liquibase.sql.UnparsedSql;

 import liquibase.sqlgenerator.SqlGenerator;

 import liquibase.sqlgenerator.SqlGeneratorChain;

 import liquibase.statement.core.UpdateStatement;

 import java.util.Date;

 public class UpdateGenerator extends AbstractSqlGenerator<UpdateStatement> {

     public ValidationErrors validate(UpdateStatement updateStatement, Database database,

             SqlGeneratorChain sqlGeneratorChain) {

         ValidationErrors validationErrors = new ValidationErrors();

         validationErrors.checkRequiredField("tableName", updateStatement.getTableName());

         validationErrors.checkRequiredField("columns", updateStatement.getNewColumnValues());

         return validationErrors;

     }

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

         StringBuffer sql = new StringBuffer("UPDATE "

                 + database.escapeTableName(statement.getSchemaName(), statement.getTableName()) + " SET");

         for (String column : statement.getNewColumnValues().keySet()) {

             sql.append(" ")

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

                     .append(" = ");

             sql.append(convertToString(statement.getNewColumnValues().get(column), database));

             sql.append(",");

         }

         sql.deleteCharAt(sql.lastIndexOf(","));

         if (statement.getWhereClause() != null) {

             String fixedWhereClause = "WHERE " + statement.getWhereClause().trim();

             for (Object param : statement.getWhereParameters()) {

                 fixedWhereClause = fixedWhereClause.replaceFirst("\\?", convertToString(param, database));

             }

             sql.append(" ").append(fixedWhereClause);

         }

         return new Sql[] { new UnparsedSql(sql.toString()) };

     }

     private String convertToString(Object newValue, Database database) {

         String sqlString;

         if (newValue == null || newValue.toString().equalsIgnoreCase("NULL")) {

             sqlString = "NULL";

         } else if (newValue instanceof String && database.shouldQuoteValue(((String) newValue))) {

             sqlString = "'" + database.escapeStringForDatabase(newValue.toString()) + "'";

         } else if (newValue instanceof Date) {

             // converting java.util.Date to java.sql.Date

             Date date = (Date) newValue;

             if (date.getClass().equals(java.util.Date.class)) {

                 date = new java.sql.Date(date.getTime());

             }

             sqlString = database.getDateLiteral(date);

         } else if (newValue instanceof Boolean) {

             if (((Boolean) newValue)) {

                 sqlString = TypeConverterFactory.getInstance().findTypeConverter(database).getBooleanType()

                         .getTrueBooleanValue();

             } else {

                 sqlString = TypeConverterFactory.getInstance().findTypeConverter(database).getBooleanType()

                         .getFalseBooleanValue();

             }

         } else {

             sqlString = newValue.toString();

         }

         return sqlString;

     }

 }