| 1 | /******************************************************************************* |
| 2 | * Copyright (c) 2014, 2015 Ericsson |
| 3 | * |
| 4 | * All rights reserved. This program and the accompanying materials are |
| 5 | * made available under the terms of the Eclipse Public License v1.0 which |
| 6 | * accompanies this distribution, and is available at |
| 7 | * http://www.eclipse.org/legal/epl-v10.html |
| 8 | * |
| 9 | * Contributors: |
| 10 | * Alexandre Montplaisir - Initial API and implementation |
| 11 | *******************************************************************************/ |
| 12 | |
| 13 | package org.eclipse.tracecompass.common.core; |
| 14 | |
| 15 | import org.eclipse.jdt.annotation.NonNull; |
| 16 | import org.eclipse.jdt.annotation.Nullable; |
| 17 | |
| 18 | /** |
| 19 | * Utility methods to handle {@link org.eclipse.jdt.annotation.NonNull} |
| 20 | * annotations. |
| 21 | * |
| 22 | * @author Alexandre Montplaisir |
| 23 | */ |
| 24 | public final class NonNullUtils { |
| 25 | |
| 26 | private NonNullUtils() {} |
| 27 | |
| 28 | /** |
| 29 | * Returns a non-null {@link String} for a potentially null object. This |
| 30 | * method calls {@link Object#toString()} if the object is not null, or |
| 31 | * returns an empty string otherwise. |
| 32 | * |
| 33 | * @param obj |
| 34 | * A {@link Nullable} object that we want converted to a string |
| 35 | * @return The non-null string |
| 36 | */ |
| 37 | public static String nullToEmptyString(@Nullable Object obj) { |
| 38 | if (obj == null) { |
| 39 | return ""; //$NON-NLS-1$ |
| 40 | } |
| 41 | String str = obj.toString(); |
| 42 | return (str == null ? "" : str); //$NON-NLS-1$ |
| 43 | } |
| 44 | |
| 45 | /** |
| 46 | * Convert a non-annotated object reference to a {@link NonNull} one. |
| 47 | * |
| 48 | * If the reference is actually null, a {@link NullPointerException} is |
| 49 | * thrown. This is usually more desirable than letting an unwanted null |
| 50 | * reference go through and fail much later. |
| 51 | * |
| 52 | * @param obj |
| 53 | * The object that is supposed to be non-null |
| 54 | * @return A {@link NonNull} reference to the same object |
| 55 | * @throws NullPointerException |
| 56 | * If the reference was actually null |
| 57 | */ |
| 58 | public static <T> T checkNotNull(@Nullable T obj) { |
| 59 | if (obj == null) { |
| 60 | throw new NullPointerException(); |
| 61 | } |
| 62 | return obj; |
| 63 | } |
| 64 | } |