Returns a primitive array by unwrapping the corresponding types. - Java Collection Framework

Java examples for Collection Framework:Array Element

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Description

Returns a primitive array by unwrapping the corresponding types.

Demo Code


//package com.java2s;
import java.lang.reflect.Array;

public class Main {
    public static void main(String[] argv) throws Exception {
        Object[] sourceArray = new String[] { "1", "abc", "level", null,
                "java2s.com", "asdf 123" };
        System.out.println(convertToPrimitiveArray(sourceArray));
    }//from  w  w  w  .  j  a  v  a2s. co m

    /**
     * Returns a primitive array by unwrapping the corresponding types. If the 
     * specified array is not an array of primitive wrapper types (e.g. <code>Integer[]</code>), 
     * an <code>IllegalArgumentException</code> will be thrown.
     * If an array element is <code>null</code>, an <code>IllegalArgumentException</code> 
     * will be thrown.
     * @param sourceArray the array
     * @return the corresponding primitive array
     * @throws IllegalArgumentException if the specified array
     *         is not an array of primitive wrapper types or if an
     *         array element is <code>null</code>
     */
    public static Object convertToPrimitiveArray(Object[] sourceArray) {
        Class componentType = sourceArray.getClass().getComponentType();
        if (componentType.equals(Boolean.class)) {
            componentType = Boolean.TYPE;
        } else if (componentType.equals(Byte.class)) {
            componentType = Byte.TYPE;
        } else if (componentType.equals(Character.class)) {
            componentType = Character.TYPE;
        } else if (componentType.equals(Short.class)) {
            componentType = Short.TYPE;
        } else if (componentType.equals(Integer.class)) {
            componentType = Integer.TYPE;
        } else if (componentType.equals(Long.class)) {
            componentType = Long.TYPE;
        } else if (componentType.equals(Float.class)) {
            componentType = Float.TYPE;
        } else if (componentType.equals(Double.class)) {
            componentType = Double.TYPE;
        } else {
            throw new IllegalArgumentException("sourceArray is of type "
                    + componentType + " which is not allowed");
        }
        int length = Array.getLength(sourceArray);
        Object targetArray = Array.newInstance(componentType, length);
        for (int ii = 0; ii < length; ii++) {
            Array.set(targetArray, ii, Array.get(sourceArray, ii));
        }
        return targetArray;
    }
}

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