org.apache.commons.collections.iterators.ArrayIterator Java Examples

/**
 * Ensures that there are no duplicate channels in the array (i.e. not using the same ChannelUID)
 *
 * @param channels the channels to check
 * @throws IllegalArgumentException in case there are duplicate channels found
 */
public static void ensureUniqueChannels(final Channel[] channels) {
    @SuppressWarnings("unchecked")
    final Iterator<Channel> it = new ArrayIterator(channels);

    ensureUniqueChannels(it, new HashSet<UID>(channels.length));
}
 

/** 
 * Gets a suitable Iterator for the given object.
 * <p>
 * This method can handles objects as follows
 * <ul>
 * <li>null - empty iterator
 * <li>Iterator - returned directly
 * <li>Enumeration - wrapped
 * <li>Collection - iterator from collection returned
 * <li>Map - values iterator returned
 * <li>Dictionary - values (elements) enumeration returned as iterator
 * <li>array - iterator over array returned
 * <li>object with iterator() public method accessed by reflection
 * <li>object - singleton iterator
 * </ul>
 * 
 * @param obj  the object to convert to an iterator
 * @return a suitable iterator, never null
 */
public static Iterator getIterator(Object obj) {
    if (obj == null) {
        return emptyIterator();
        
    } else if (obj instanceof Iterator) {
        return (Iterator) obj;
        
    } else if (obj instanceof Collection) {
        return ((Collection) obj).iterator();
        
    } else if (obj instanceof Object[]) {
        return new ObjectArrayIterator((Object[]) obj);
        
    } else if (obj instanceof Enumeration) {
        return new EnumerationIterator((Enumeration) obj);
        
    } else if (obj instanceof Map) {
        return ((Map) obj).values().iterator();
        
    } else if (obj instanceof Dictionary) {
        return new EnumerationIterator(((Dictionary) obj).elements());
        
    } else if (obj != null && obj.getClass().isArray()) {
        return new ArrayIterator(obj);
        
    } else {
        try {
            Method method = obj.getClass().getMethod("iterator", null);
            if (Iterator.class.isAssignableFrom(method.getReturnType())) {
                Iterator it = (Iterator) method.invoke(obj, null);
                if (it != null) {
                    return it;
                }
            }
        } catch (Exception ex) {
            // ignore
        }
        return singletonIterator(obj);
    }
}
 

/**
 * Gets an iterator over an object or primitive array.
 * <p>
 * This method will handle primitive arrays as well as object arrays.
 * The primitives will be wrapped in the appropriate wrapper class.
 *
 * @param array  the array over which to iterate
 * @return  an iterator over the array
 * @throws IllegalArgumentException if the array is not an array
 * @throws NullPointerException if array is null
 */
public static ResettableIterator arrayIterator(Object array) {
    return new ArrayIterator(array);
}
 

/**
 * Gets an iterator over the end part of an object or primitive array.
 * <p>
 * This method will handle primitive arrays as well as object arrays.
 * The primitives will be wrapped in the appropriate wrapper class.
 *
 * @param array  the array over which to iterate
 * @param start  the index to start iterating at
 * @return an iterator over part of the array
 * @throws IllegalArgumentException if the array is not an array
 * @throws IndexOutOfBoundsException if start is less than zero or greater
 *  than the length of the array
 * @throws NullPointerException if array is null
 */
public static ResettableIterator arrayIterator(Object array, int start) {
    return new ArrayIterator(array, start);
}
 

/**
 * Gets an iterator over part of an object or primitive array.
 * <p>
 * This method will handle primitive arrays as well as object arrays.
 * The primitives will be wrapped in the appropriate wrapper class.
 *
 * @param array  the array over which to iterate
 * @param start  the index to start iterating at
 * @param end  the index to finish iterating at
 * @return an iterator over part of the array
 * @throws IllegalArgumentException if the array is not an array
 * @throws IndexOutOfBoundsException if array bounds are invalid
 * @throws IllegalArgumentException if end is before start
 * @throws NullPointerException if array is null
 */
public static ResettableIterator arrayIterator(Object array, int start, int end) {
    return new ArrayIterator(array, start, end);
}