package liquibase.ext.spatial.sqlgenerator;
   
   import java.util.Map.Entry;
   
   import liquibase.database.Database;
   import liquibase.exception.ValidationErrors;
   import liquibase.sql.Sql;
   import liquibase.sqlgenerator.SqlGeneratorChain;
   import liquibase.sqlgenerator.core.UpdateGenerator;
  import liquibase.statement.core.UpdateStatement;
  
  /**
   * Implementations of <code>AbstractSpatialInsertGenerator</code> convert a Well-Known Text string
   * and EPSG SRID string to the database-specific geometry.
   * 
   * @author Lonny
   */
  public abstract class AbstractSpatialUpdateGenerator extends UpdateGenerator implements
        WktInsertOrUpdateGenerator {
     @Override
     public int getPriority() {
        return super.getPriority() + 1;
     }
  
     @Override
     public ValidationErrors validate(final UpdateStatement statement, final Database database,
           final SqlGeneratorChain sqlGeneratorChain) {
        return sqlGeneratorChain.validate(statement, database);
     }
  
     /**
      * Find any fields that look like WKT or EWKT and replace them with the database-specific value.
      */
     @Override
     public Sql[] generateSql(final UpdateStatement statement, final Database database,
           final SqlGeneratorChain sqlGeneratorChain) {
        for (final Entry<String, Object> entry : statement.getNewColumnValues().entrySet()) {
           entry.setValue(handleColumnValue(entry.getValue(), database));
        }
        return super.generateSql(statement, database, sqlGeneratorChain);
     }
  
     /**
      * @see liquibase.sqlgenerator.core.AbstractSqlGenerator#looksLikeFunctionCall(java.lang.String,
      *      liquibase.database.Database)
      */
     @Override
     public boolean looksLikeFunctionCall(final String value, final Database database) {
        final boolean result;
        if (value.trim().toUpperCase().startsWith(getGeomFromWktFunction().trim().toUpperCase())) {
           result = true;
        } else {
           result = super.looksLikeFunctionCall(value, database);
        }
        return result;
     }
  
     /**
      * Indicates if the SRID parameter is required in the function returned from
      * {@link #getGeomFromWktFunction()}.
      * 
      * @param database
      *           the database instance.
      * 
      * @return <code>true</code> if the SRID parameter is required in order to invoke the function.
      */
     @Override
     public boolean isSridRequiredInFunction(final Database database) {
        return false;
     }
  
     /**
      * If the old value is a geometry or a Well-Known Text, convert it to the appropriate new value.
      * Otherwise, this method returns the old value.
      * 
      * @param oldValue
      *           the old value.
      * @param database
      *           the database instance.
      * 
      * @return the new value.
      */
     protected Object handleColumnValue(final Object oldValue, final Database database) {
        final Object newValue = WktConversionUtils.handleColumnValue(oldValue, database, this);
        return newValue;
     }
  
     /**
      * @param wkt
      *           the Well-Known Text string.
      * @param srid
      *           the SRID string which may be an empty string.
      * @param database
      *           the database instance.
      * @return the string that converts the WKT to a database-specific geometry.
      */
     @Override
     public String convertToFunction(final String wkt, final String srid, final Database database) {
        final String function = WktConversionUtils.convertToFunction(wkt, srid, database, this);
       return function;
    }
 }