Java Map from Array toMap(Object[] array)

Description

Converts the given array into a java.util.Map .

License

Open Source License

Parameter

Parameter	Description
array	an array whose elements are either a java.util.Map.Entry or an Array containing at least two elements, may be null

Exception

Parameter	Description
IllegalArgumentException	if the array contains elements otherthan java.util.Map.Entry and an Array

Return

a Map that was created from the array

Declaration

public static Map<Object, Object> toMap(Object[] array) 

Method Source Code

//package com.java2s;

import java.util.HashMap;

import java.util.Map;

public class Main {
    /**//from   w  w  w  . j  a v  a  2 s  .  c  om
     * <p>Converts the given array into a {@link java.util.Map}. Each element of the array
     * must be either a {@link java.util.Map.Entry} or an Array, containing at least two
     * elements, where the first element is used as key and the second as
     * value.</p>
     *
     * <p>This method can be used to initialize:</p>
     * <pre>
     * // Create a Map mapping colors.
     * Map colorMap = MapUtils.toMap(new String[][] {{
     *     {"RED", "#FF0000"},
     *     {"GREEN", "#00FF00"},
     *     {"BLUE", "#0000FF"}});
     * </pre>
     *
     * <p>This method returns {@code null} for a {@code null} input array.</p>
     *
     * @param array  an array whose elements are either a {@link java.util.Map.Entry} or
     *  an Array containing at least two elements, may be {@code null}
     * @return a {@code Map} that was created from the array
     * @throws IllegalArgumentException  if one element of this Array is
     *  itself an Array containing less then two elements
     * @throws IllegalArgumentException  if the array contains elements other
     *  than {@link java.util.Map.Entry} and an Array
     */
    public static Map<Object, Object> toMap(Object[] array) {
        if (array == null) {
            return null;
        }
        final Map<Object, Object> map = new HashMap<Object, Object>((int) (array.length * 1.5));
        for (int i = 0; i < array.length; i++) {
            Object object = array[i];
            if (object instanceof Map.Entry<?, ?>) {
                Map.Entry<?, ?> entry = (Map.Entry<?, ?>) object;
                map.put(entry.getKey(), entry.getValue());
            } else if (object instanceof Object[]) {
                Object[] entry = (Object[]) object;
                if (entry.length < 2) {
                    throw new IllegalArgumentException(
                            "Array element " + i + ", '" + object + "', has a length less than 2");
                }
                map.put(entry[0], entry[1]);
            } else {
                throw new IllegalArgumentException(
                        "Array element " + i + ", '" + object + "', is neither of type Map.Entry nor an Array");
            }
        }
        return map;
    }
}

Related

1. toMap(Object... objects)
2. toMap(Object... objects)
3. toMap(Object... pairs)
4. toMap(Object... pairs)
5. toMap(Object[] array)
6. toMap(Object[] array, Map map)
7. toMap(Object[] keys, Object[] values)
8. toMap(Object[][] array)