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ResultImpl.javaAPI DocGlassfish v2 API6661Sat May 05 19:17:54 BST 2007org.apache.taglibs.standard.tag.common.sql

ResultImpl

public class ResultImpl extends Object implements javax.servlet.jsp.jstl.sql.Result

This class creates a cached version of a ResultSet. It's represented as a Result implementation, capable of returing an array of Row objects containing a Column instance for each column in the row.

Note -- this is a private copy for the RI to avoid making the corresponding class in javax.servlet.* public.

author
Hans Bergsten
author
Justyna Horwat

Fields Summary
private List
rowMap
private List
rowByIndex
private String[]
columnNames
private boolean
isLimited
Constructors Summary
public ResultImpl(ResultSet rs, int startRow, int maxRows)
This constructor reads the ResultSet and saves a cached copy.

param
rs an open ResultSet, positioned before the first row
param
startRow, beginning row to be cached
param
maxRows, query maximum rows limit
exception
if a database error occurs

        rowMap = new ArrayList();
        rowByIndex = new ArrayList();

        ResultSetMetaData rsmd = rs.getMetaData();
        int noOfColumns = rsmd.getColumnCount();

        // Create the column name array
        columnNames = new String[noOfColumns];
        for (int i = 1; i <= noOfColumns; i++) {
            columnNames[i-1] = rsmd.getColumnName(i);
        }

        // Throw away all rows upto startRow
        for (int i = 0; i < startRow; i++) {
            rs.next();
        }

        // Process the remaining rows upto maxRows
        int processedRows = 0;
        while (rs.next()) {
            if ((maxRows != -1) && (processedRows == maxRows)) {
                isLimited = true; 
                break;
            }
            Object[] columns = new Object[noOfColumns];
            SortedMap columnMap = 
                new TreeMap(String.CASE_INSENSITIVE_ORDER);

            // JDBC uses 1 as the lowest index!
            for (int i = 1; i <= noOfColumns; i++) {
                Object value =  rs.getObject(i);
                if (rs.wasNull()) {
                    value = null;
                }
                columns[i-1] = value;
                columnMap.put(columnNames[i-1], value);
            }
            rowMap.add(columnMap);
            rowByIndex.add(columns);
            processedRows++;
        }
Methods Summary
public java.lang.String[]getColumnNames()
Returns an array of String objects. The array represents the names of the columns arranged in the same order as in the getRowsByIndex() method.

return
an array of String[]

        return columnNames;
public intgetRowCount()
Returns the number of rows in the cached ResultSet

return
the number of cached rows, or -1 if the Result could not be initialized due to SQLExceptions

        if (rowMap == null) {
            return -1;
        }
        return rowMap.size();
public java.util.SortedMap[]getRows()
Returns an array of SortedMap objects. The SortedMap object key is the ColumnName and the value is the ColumnValue. SortedMap was created using the CASE_INSENSITIVE_ORDER Comparator so the key is the case insensitive representation of the ColumnName.

return
an array of Map, or null if there are no rows

        if (rowMap == null) {
            return null;
        }

        //should just be able to return SortedMap[] object
        return (SortedMap []) rowMap.toArray(new SortedMap[0]);
public java.lang.Object[][]getRowsByIndex()
Returns an array of Object[] objects. The first index designates the Row, the second the Column. The array stores the value at the specified row and column.

return
an array of Object[], or null if there are no rows

        if (rowByIndex == null) {
            return null;
        }

        //should just be able to return Object[][] object
        return (Object [][])rowByIndex.toArray(new Object[0][0]);
public booleanisLimitedByMaxRows()
Returns true of the query was limited by a maximum row setting

return
true if the query was limited by a MaxRows attribute

        return isLimited;