Application: gvSIG desktop

package org.gvsig.expressionevaluator.impl;

import java.util.UUID;

import org.gvsig.expressionevaluator.ExpressionBuilder;

import org.gvsig.expressionevaluator.ExpressionBuilder.Value;

import org.gvsig.expressionevaluator.ExpressionUtils;

import static org.gvsig.fmap.dal.DataManager.FUNCTION_CURRENT_ROW;

import static org.gvsig.fmap.dal.DataManager.FUNCTION_CURRENT_STORE;

import static org.gvsig.fmap.dal.DataManager.FUNCTION_EXISTS;

import static org.gvsig.fmap.dal.DataManager.FUNCTION_FOREING_VALUE;

import static org.gvsig.fmap.dal.DataManager.FUNCTION_ISSELECTED_CURRENT_ROW;

import static org.gvsig.fmap.dal.DataManager.FUNCTION_SELECT;

import static org.gvsig.fmap.dal.DataManager.FUNCTION_SELECT_COUNT;

import org.gvsig.fmap.dal.expressionevaluator.DALExpressionBuilder;

/**

 *

 * @author jjdelcerro

 */

public class DefaultDALExpressionBuilder implements DALExpressionBuilder {

  private class DefaultSelectBuilder implements SelectBuilder {

    private Value columns;

    private String tableName;

    private Value where;

    private Long limit;

    private final ExpressionBuilder.Function order;

    private final ExpressionBuilder.Function order_mode;

    public DefaultSelectBuilder() {

      this.columns = expression().tuple(); // ALL === empty tuple

      this.where = null;

      this.order = expression().tuple();

      this.order_mode = expression().tuple();

      this.limit = null;

    }

    @Override

    public SelectBuilder column(String name) {

      ((ExpressionBuilder.Function)columns).parameter(expression().column(name));

      return this;

    }

    @Override

    public SelectBuilder column_all() {

      this.columns = expression().tuple(); // ALL === empty tuple

      return this;

    }

    @Override

    public SelectBuilder table(String tableName) {

      this.tableName = tableName;

      return this;

    }

    @Override

    public SelectBuilder where(ExpressionBuilder.Value where) {

      this.where = where;

      return this;

    }

    @Override

    public SelectBuilder order(String columnName, boolean asc) {

      this.order.parameter(expression().variable(columnName));

      this.order_mode.parameter(expression().constant(asc));

      return this;

    }

    @Override

    public SelectBuilder limit(long limit) {

      this.limit = limit;

      return this;

    }

    @Override

    public ExpressionBuilder.Value toValue() {

      ExpressionBuilder.Function select = expression().function(FUNCTION_SELECT);

      select.parameter(columns);

      select.parameter(expression().variable(tableName));

      select.parameter(where);

      select.parameter(order);

      select.parameter(order_mode);

      select.parameter(expression().constant(limit));

      return select;

    }

    @Override

    public String toString() {

      return this.toValue().toString();

    }

  }

  private class DefaultSelectCountBuilder implements SelectCountBuilder {

    private String tableName;

    private Value where;

    public DefaultSelectCountBuilder() {

    }

    @Override

    public SelectCountBuilder table(String tableName) {

      this.tableName = tableName;

      return this;

    }

    @Override

    public SelectCountBuilder where(ExpressionBuilder.Value where) {

      this.where = where;

      return this;

    }

    @Override

    public ExpressionBuilder.Value toValue() {

      ExpressionBuilder.Function select = expression().function(FUNCTION_SELECT_COUNT);

      select.parameter(expression().variable(tableName));

      if( where != null ) {

        select.parameter(where);

      }

      return select;

    }

    @Override

    public String toString() {

      return this.toValue().toString();

    }

  }

  private ExpressionBuilder expressionBuilder;

  @Override

  public ExpressionBuilder expression() {

    if( this.expressionBuilder == null ) {

      this.expressionBuilder = ExpressionUtils.createExpressionBuilder();

    }

    return this.expressionBuilder;

  }

  @Override

  public SelectBuilder select() {

    return new DefaultSelectBuilder();

  }

  @Override

  public SelectCountBuilder select_count() {

    return new DefaultSelectCountBuilder();

  }

  @Override

  public ExpressionBuilder.Function exists(Value list) {

    return exists(list, null);

  }

  @Override

  public ExpressionBuilder.Function exists(Value list, String exists_id) {

      if( exists_id==null ) {

        exists_id = "EXISTS"+UUID.randomUUID().toString().replaceAll("-", "");

      }

      ExpressionBuilder.Function exists = expression().function(

              FUNCTION_EXISTS,

              list, 

              expression().constant(exists_id)

      );

      return exists;

  }

  @Override

  public ExpressionBuilder.Function foreing_value(String attrlocal, String attrforeing) {

    ExpressionBuilder.Function foreing_value = expression().function(

          FUNCTION_FOREING_VALUE,

          expression().tuple(

                  expression().constant(attrlocal),

                  expression().constant(attrforeing)

          )

    );

    return foreing_value;

  }

  @Override

  public ExpressionBuilder.Function current_row() {

    return expression().function(FUNCTION_CURRENT_ROW);

  }

  @Override

  public ExpressionBuilder.Function current_table() {

    return expression().function(FUNCTION_CURRENT_STORE);

  }

  @Override

  public ExpressionBuilder.Function isselected_current_row() {

    return expression().function(FUNCTION_ISSELECTED_CURRENT_ROW);

  }

}