view src/main/java/nl/cwi/monetdb/embedded/resultset/QueryResultSetBooleanColumn.java @ 82:4231a7f5cdc3 embedded

Added better null values mapping for JDBC embedded connection compatibility. The previous potential bug on boolean columns in now fixed
author Pedro Ferreira <pedro.ferreira@monetdbsolutions.com>
date Tue, 27 Dec 2016 17:23:38 +0000 (2016-12-27)
parents 86967be24645
children
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/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0.  If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * Copyright 2016 MonetDB B.V.
 */

package nl.cwi.monetdb.embedded.resultset;

import nl.cwi.monetdb.embedded.env.MonetDBEmbeddedException;

/**
 * A MonetDB column converted to an array of Java boolean values.
 *
 * @author <a href="mailto:pedro.ferreira@monetdbsolutions.com">Pedro Ferreira</a>
 */
public final class QueryResultSetBooleanColumn extends AbstractQueryResultSetColumn<boolean[]> {

    /**
     * Gets MonetDB's boolean null constant
     *
     * @return MonetDB's boolean null constant
     */
    public static native boolean GetBooleanNullConstant();

    /**
     * Due to restrictions on the representation of boolean values in the Java language, this method should be called
     * to check if a boolean value is null or not.
     *
     * @param value The value to evaluate
     * @return If the value is null or not
     */
    public static native boolean CheckBooleanIsNull(boolean value);

    /**
     * Array with the retrieved values.
     */
    private final boolean[] values;

    protected QueryResultSetBooleanColumn(String columnType, long tablePointer, int resultSetIndex, String columnName,
                                          int columnDigits, int columnScale, int numberOfRows) {
        super(columnType, tablePointer, resultSetIndex, columnName, columnDigits, columnScale, numberOfRows);
        if(!this.getMapping().getJavaClass().equals(Boolean.class)) {
            throw new ClassCastException("The parameter must be of boolean type!!");
        }
        this.values = new boolean[numberOfRows];
    }

    @Override
    protected void fetchMoreData(int startIndex, int endIndex) throws MonetDBEmbeddedException {
        this.fetchValuesInternal(this.tablePointer, this.resultSetIndex, startIndex, endIndex, this.values, this.nullValues);
    }

    @Override
    protected boolean[] storeNewDataAndGetResult(int startIndex, int numberOfRowsToRetrieve) {
        boolean[] result = new boolean[numberOfRowsToRetrieve];
        System.arraycopy(this.values, startIndex, result, 0, numberOfRowsToRetrieve);
        return result;
    }

    @Override
    protected Boolean[] mapValuesToObjectArrayImplementation(int startIndex, int numberOfRowsToRetrieve) {
        Boolean[] res = new Boolean[numberOfRowsToRetrieve];
        int endIndex = startIndex + numberOfRowsToRetrieve;
        for(int i = startIndex, j = 0 ; i < endIndex ; i++, j++) {
            res[j] = (this.nullValues[i]) ? null : this.values[i];
        }
        return res;
    }

    /**
     * Internal implementation to fetch values from the column.
     */
    private native void fetchValuesInternal(long tablePointer, int resultSetIndex, int startIndex, int endIndex,
                                            boolean[] values, boolean[] nullValues) throws MonetDBEmbeddedException;
}