SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package net.multiphasicapps.collections;

import cc.squirreljme.runtime.cldc.util.UnmodifiableIterator;
import java.util.Iterator;
import org.jetbrains.annotations.UnmodifiableView;

/**
 * Wraps an iterable which makes it not able to be modified.
 *
 * @param <T> The type to iterate through.
 * @since 2021/04/25
 */
@UnmodifiableView
public final class UnmodifiableIterable<T>
    implements Iterable<T>
{
    /** The iterable used. */
    private final Iterable<T> iterable;
    
    /**
     * Initializes the unmodifiable iterable.
     * 
     * @param __it The iterable used.
     * @throws NullPointerException On null arguments.
     * @since 2021/04/25
     */
    UnmodifiableIterable(Iterable<T> __it)
        throws NullPointerException
    {
        if (__it == null)
            throw new NullPointerException("NARG");
        
        this.iterable = __it;
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/04/25
     */
    @Override
    public Iterator<T> iterator()
    {
        return UnmodifiableIterator.<T>of(this.iterable);
    }
    
    /**
     * Returns an unmodifiable iterable from the given one.
     * 
     * @param <T> The type used.
     * @param __it The iterator to wrap.
     * @return The iterable but it cannot be modified.
     * @throws NullPointerException On null arguments.
     * @since 2021/04/25
     */
    public static <T> Iterable<T> of(Iterable<T> __it)
        throws NullPointerException
    {
        if (__it == null)
            throw new NullPointerException("NARG");
        
        return new UnmodifiableIterable<>(__it);
    }
}