groovy.transform.AutoFinal Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package groovy.transform;
import org.codehaus.groovy.control.CompilerConfiguration;
import org.codehaus.groovy.transform.GroovyASTTransformationClass;
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;
/**
* Annotation to automatically add the final qualifier to method, constructor,
* and closure parameters.
* The annotation can be placed at the class level in which case it applies to
* all methods, constructors, and closures within the class and any inner classes.
* It can also be applied to an individual method, constructor, field with a
* Closure initial value or a Closure assigned to a local variable. In the case
* of fields (or local variables) it only adjusts the parameters of the referenced
* Closure not the field (or local variable) itself.
*
If you wish to automatically apply the
* annotation to all classes of a project, consider using
* {@code groovyc --configscript}. Google "Customising The Groovy Compiler",
* or see {@link CompilerConfiguration} for further details.
* This will ensure that all arguments will automatically be final,
* completely eliminating the need to clutter the code with final keywords
* in any parameter list.
*
* Example usage:
*
* {@code @groovy.transform.AutoFinal}
* class Person {
* final String first, last
* Person(String first, String last) {
* this.first = first
* this.last = last
* }
* String fullName(boolean reversed = false, String separator = ' ') {
* final concatCls = { String n0, String n1 {@code ->} "$n0$separator$n1" }
* concatCls(reversed ? last : first, reversed ? first : last)
* }
* }
*
* final js = new Person('John', 'Smith')
* assert js.fullName() == 'John Smith'
* assert js.fullName(true, ', ') == 'Smith, John'
*
* for this case, the constructor for the Person class will be
* equivalent to the following code:
*
* Person(final String first, final String last) {
* ...
* }
*
* And after normal default parameter processing takes place, the following overloaded methods will exist:
*
* String fullName(final boolean reversed, final String separator) { ... }
* String fullName(final boolean reversed) { fullName(reversed, ' ') }
* String fullName() { fullName(false) }
*
* and the closure will have become:
*
* { final String n0, final String n1 {@code ->} "$n0$separator$n1" }
*
*
* @since 2.5.0
*/
@Documented
@Retention(RetentionPolicy.SOURCE)
@Target({ElementType.TYPE, ElementType.METHOD, ElementType.CONSTRUCTOR, ElementType.FIELD, ElementType.LOCAL_VARIABLE})
@GroovyASTTransformationClass("org.codehaus.groovy.transform.AutoFinalASTTransformation")
public @interface AutoFinal {
/**
* Indicates that adding final to parameters should not be applied on this node.
* Normally not required since leaving off the annotation will achieve the same effect.
* However, it can be useful for selectively disabling this annotation in just a small part
* of an otherwise annotated class. As an example, it would make sense to set this to {@code false} on
* a method which altered parameters in a class already marked as {@code @AutoFinal}.
* All nodes in the class except that single method would be processed.
*/
boolean enabled() default true;
}