JCArray.java

package ee.esutoniagodesu.util;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * class for various static operations with arrays
 */
public final class JCArray {

    /**
     * Reallocates an array with a new size, and copies the contents of the old
     * array to the new array.
     *
     * @param oldArray the old array, to be reallocated.
     * @param newSize  the new array size.
     * @return A new array with the same contents.
     */
    @SuppressWarnings("SuspiciousSystemArraycopy")
    public static Object resizeArray(Object oldArray, int newSize) {
        int oldSize = java.lang.reflect.Array.getLength(oldArray);
        Class elementType = oldArray.getClass().getComponentType();
        Object newArray = java.lang.reflect.Array.newInstance(elementType,
            newSize);
        int preserveLength = Math.min(oldSize, newSize);
        if (preserveLength > 0) {
            System.arraycopy(oldArray, 0, newArray, 0, preserveLength);
        }
        return newArray;
    }

    public static void print(int[] arr) {
        String print = "";
        for (int anArr : arr) {
            print += anArr + " ";
        }

        System.out.println("------");
        System.out.println(print);
        System.out.println("------");

    }

    /**
     * @param arr - two-dimensional array
     */
    public static void print(double[][] arr) {
        for (double[] anArr : arr) {
            for (int j = 0; j < arr[0].length; j++) {
                System.out.print(anArr[j] + "	");
            }
            System.out.println();
        }
    }

    /**
     * @param arr - one-dimensional array
     */
    public static void print(double[] arr) {
        for (double anArr : arr) {
            System.out.print(anArr + " ");
        }
    }

    public static List<Map> resultSetToArrayList(ResultSet rs)
        throws SQLException {

        ResultSetMetaData md = rs.getMetaData();
        int columns = md.getColumnCount();
        List<Map> results = new ArrayList<>();

        while (rs.next()) {

            Map row = new HashMap();

            results.add(row);

            for (int i = 1; i <= columns; i++) {

                row.put(md.getColumnName(i), rs.getObject(i));
            }
        }
        return results;
    }
}