// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package io.flutter.util;

/**
 * Static convenience methods that help a method or constructor check whether
 * it was invoked correctly (that is, whether its <i>preconditions</i> were
 * met).
 */
public final class Preconditions {
    private Preconditions() {}

    /**
     * Ensures that an object reference passed as a parameter to the calling
     * method is not null.
     *
     * @param reference an object reference
     * @return the non-null reference that was validated
     * @throws NullPointerException if {@code reference} is null
     */
    public static <T> T checkNotNull(T reference) {
        if (reference == null) {
            throw new NullPointerException();
        }
        return reference;
    }
}