NonNull.java

/*
 * Copyright (C) 2009-2013 The Project Lombok Authors.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package lombok;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * If put on a parameter, lombok will insert a null-check at the start of the method / constructor's body, throwing a
 * {@code NullPointerException} with the parameter's name as message. If put on a field, any generated method assigning
 * a value to this field will also produce these nullchecks.
 * <p>
 * Note that any annotation named {@code NonNull} with any casing and any package will result in nullchecks produced for
 * generated methods (and the annotation will be copied to the getter return type and any parameters of generated methods),
 * but <em>only</em> this annotation, if present on a parameter, will result in a null check inserted into your otherwise
 * handwritten method.
 *
 * WARNING: If the java community ever does decide on supporting a single {@code @NonNull} annotation (for example via JSR305), then
 * this annotation will <strong>be deleted</strong> from the lombok package. If the need to update an import statement scares
 * you, you should use your own annotation named {@code @NonNull} instead of this one.
 */
@Target({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER, ElementType.LOCAL_VARIABLE})
@Retention(RetentionPolicy.CLASS)
@Documented
public @interface NonNull {
}