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package org.apache.taglibs.standard.tag.el.sql;

import javax.servlet.jsp.JspException;

import org.apache.taglibs.standard.lang.support.ExpressionEvaluatorManager;
import org.apache.taglibs.standard.tag.common.sql.QueryTagSupport;

/**
 * Subclass for the JSTL library with EL support.
 *
 * @author Hans Bergsten
 * @author Justyna Horwat
 */
public class QueryTag extends QueryTagSupport {

    private String dataSourceEL;
    private String sqlEL;
    private String startRowEL;
    private String maxRowsEL;

    //*********************************************************************
    // Constructor

    /**
     * Constructs a new QueryTag.  As with TagSupport, subclasses
     * should not provide other constructors and are expected to call
     * the superclass constructor
     */
    public QueryTag() {
        super();
    }

    //*********************************************************************
    // Accessor methods

    public void setDataSource(String dataSourceEL) {
	this.dataSourceEL = dataSourceEL;
	this.dataSourceSpecified = true;
    }

    /**
     * The index of the first row returned can be
     * specified using startRow.
     */
    public void setStartRow(String startRowEL) {
	this.startRowEL = startRowEL;
    }

    /**
     * Query result can be limited by specifying
     * the maximum number of rows returned.
     */
    public void setMaxRows(String maxRowsEL) {
	this.maxRowsEL = maxRowsEL;
	this.maxRowsSpecified = true;
    }

    /**
     * Setter method for the SQL statement to use for the
     * query. The statement may contain parameter markers
     * (question marks, ?). If so, the parameter values must
     * be set using nested value elements.
     */
    public void setSql(String sqlEL) {
	this.sqlEL = sqlEL;
    }

    public int doStartTag() throws JspException {
        evaluateExpressions();
	return super.doStartTag();
    }

    //*********************************************************************
    // Private utility methods

    // Evaluates expressions as necessary
    private void evaluateExpressions() throws JspException {
        Integer tempInt = null;

        if (dataSourceEL != null) {
            rawDataSource = (Object) ExpressionEvaluatorManager.evaluate(
                "dataSource", dataSourceEL, Object.class, this, pageContext);
        }

        if (sqlEL != null) {
            sql = (String) ExpressionEvaluatorManager.evaluate("sql", sqlEL,
                String.class, this, pageContext);
        }

	if (startRowEL != null) {
	    tempInt = (Integer) ExpressionEvaluatorManager.evaluate(
                "startRow", startRowEL, Integer.class, this, pageContext);
	    if (tempInt != null)
		startRow = tempInt.intValue();
	}

	if (maxRowsEL != null) {
	    tempInt = (Integer) ExpressionEvaluatorManager.evaluate(
                "maxRows", maxRowsEL, Integer.class, this, pageContext);
	    if (tempInt != null)
		maxRows = tempInt.intValue();
	}
    }
}