Java Array Copy arraycopy(T[] src, int srcPos, T[] dest, int destPos, int length)

Description

Short-hand method for deciding whether or not to use the native System#arraycopy(Object,int,Object,int,int) method or an element-by-element copy, based on the #JNI_COPY_ARRAY_THRESHOLD .

License

Open Source License

Parameter

Parameter	Description
src	The source array.
srcPos	The source starting position.
dest	The destination array.
destPos	The destination starting position.
length	The amount of bytes to copy.

Declaration

private static <T> void arraycopy(T[] src, int srcPos, T[] dest, int destPos, int length)

Method Source Code

//package com.java2s;
//License from project: Open Source License 

public class Main {
    /**/*w w  w  . ja va2 s. c om*/
     * Empirically determined point at which the average cost of a JNI call exceeds the expense
     * of an element-by-element copy. This number may change over time.
     */
    private static final int JNI_COPY_ARRAY_THRESHOLD = 6;

    /**
     * Short-hand method for deciding whether or not to use the native
     * {@link System#arraycopy(Object, int, Object, int, int)} method or an element-by-element
     * copy, based on the {@link #JNI_COPY_ARRAY_THRESHOLD}.
     * 
     * @param src
     *            The source array.
     * @param srcPos
     *            The source starting position.
     * @param dest
     *            The destination array.
     * @param destPos
     *            The destination starting position.
     * @param length
     *            The amount of bytes to copy.
     */
    private static <T> void arraycopy(T[] src, int srcPos, T[] dest, int destPos, int length) {
        if (length >= JNI_COPY_ARRAY_THRESHOLD) {
            System.arraycopy(src, srcPos, dest, destPos, length);
        } else {
            for (int i = 0; i < length; i++) {
                dest[destPos + i] = src[srcPos + i];
            }
        }
    }
}