8  * http://www.apache.org/licenses/LICENSE-2.0
11  * distributed under the License is distributed on an "AS IS" BASIS,
21  * An adaptation of Guava's {@code com.google.common.base.Preconditions} that is specially tailored
26    * Ensures that an object reference passed as a parameter to the calling method is not null.
28    * @param reference an object reference
29    * @return the non-null reference that was validated
30    * @throws NullPointerException if {@code reference} is null
32   public static <T> T checkNotNull(T reference) {  in checkNotNull()  argument
33     if (reference == null) {  in checkNotNull()
36     return reference;  in checkNotNull()
40    * Ensures that an object reference passed as a parameter to the calling method is not null.
42    * @param reference an object reference
44    * @return the non-null reference that was validated
45    * @throws NullPointerException if {@code reference} is null
47   public static <T> T checkNotNull(T reference, String errorMessage) {  in checkNotNull()  argument
48     if (reference == null) {  in checkNotNull()
51     return reference;  in checkNotNull()
55    * Ensures that an object reference returned from a provides method is not null.
57    * @param reference an object reference
58    * @return the non-null reference that was validated
59    * @throws NullPointerException if {@code reference} is null
61   public static <T> T checkNotNullFromProvides(T reference) {  in checkNotNullFromProvides()  argument
62     if (reference == null) {  in checkNotNullFromProvides()
63       throw new NullPointerException("Cannot return null from a non-@Nullable @Provides method");  in checkNotNullFromProvides()
65     return reference;  in checkNotNullFromProvides()
69    * Ensures that an object reference returned from a component method is not null.
71    * @param reference an object reference
72    * @return the non-null reference that was validated
73    * @throws NullPointerException if {@code reference} is null
75   public static <T> T checkNotNullFromComponent(T reference) {  in checkNotNullFromComponent()  argument
76     if (reference == null) {  in checkNotNullFromComponent()
77       throw new NullPointerException("Cannot return null from a non-@Nullable component method");  in checkNotNullFromComponent()
79     return reference;  in checkNotNullFromComponent()
83    * Ensures that an object reference passed as a parameter to the calling method is not null.
85    * @param reference an object reference
87    *     message is formed by replacing the single {@code %s} placeholder in the template with
92    * @return the non-null reference that was validated
93    * @throws NullPointerException if {@code reference} is null
98       T reference, String errorMessageTemplate, Object errorMessageArg) {  in checkNotNull()  argument
99     if (reference == null) {  in checkNotNull()
100       // Simple implementation of String.format, which is not GWT-compatible  in checkNotNull()
114     return reference;  in checkNotNull()
120    * @throws IllegalStateException if {@code requirement is null}