keycloakjar.com.google.errorprone.annotations.CompileTimeConstant Maven / Gradle / Ivy
Show all versions of camunda-platform-7-keycloak-run Show documentation
/*
* Copyright 2015 The Error Prone Authors.
*
* Licensed 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 com.google.errorprone.annotations;
import static java.lang.annotation.RetentionPolicy.CLASS;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
/**
* Annotation for method parameter and class field declarations, which denotes that corresponding
* actual values must be compile-time constant expressions.
*
* When the formal parameter of a method or constructor is annotated with the {@link
* CompileTimeConstant} type annotation, the corresponding actual parameter must be an expression
* that satisfies one of the following conditions:
*
*
* - The expression is one for which the Java compiler can determine a constant value at compile
* time, or
*
- the expression consists of the literal {@code null}, or
*
- the expression consists of a single identifier, where the identifier is a formal method
* parameter or class field that is declared {@code final} and has the {@link
* CompileTimeConstant} annotation.
*
*
* This constraint on call sites of methods or constructors that have one or more formal
* parameters with this annotation is enforced by error-prone.
*
*
For example, the following code snippet is legal:
*
*
{@code
* public class C {
* private static final String S = "Hello";
* void m(@CompileTimeConstant final String s) { }
* void n(@CompileTimeConstant final String t) {
* m(S + " World!");
* m(null);
* m(t);
* }
* }
* }
*
* In contrast, the following is illegal:
*
*
{@code
* public class C {
* void m(@CompileTimeConstant final String s) { }
* void n(String t) {
* m(t);
* }
* }
* }
*
* When a class field is annotated with the {@link CompileTimeConstant} type annotation, the
* field must also be declared to be {@code final}, and the corresponding initialised value must be
* an expression that satisfies one of the following conditions:
*
*
* - The expression is one for which the Java compiler can determine a constant value at compile
* time, or
*
- the expression consists of the literal {@code null}, or
*
- the expression consists of a single identifier, where the identifier is a formal method
* parameter or class field that is declared {@code final} and has the {@link
* CompileTimeConstant} annotation.
*
*
* This constraint on fields with this annotation is enforced by error-prone.
*
*
For example, the following code snippet is legal:
*
*
{@code
* public class C {
* \@CompileTimeConstant final String S;
* public C(@CompileTimeConstant String s) {
* this.S = s;
* }
* void m(@CompileTimeConstant final String s) { }
* void n() {
* m(S);
* }
* }
* }
*
* In contrast, the following are illegal:
*
*
{@code
* public class C {
* \@CompileTimeConstant String S;
* public C(@CompileTimeConstant String s) {
* this.S = s;
* }
* void m(@CompileTimeConstant final String s) { }
* void n() {
* m(S);
* }
* }
* }
*
* {@code
* public class C {
* \@CompileTimeConstant final String S;
* public C(String s) {
* this.S = s;
* }
* }
* }
*
* Compile-time constant values are implicitly under the control of the trust domain of the
* application whose source code they are part of. Hence, this annotation is useful to constrain the
* use of APIs that may only be safely called with values that are under application control.
*
*
The current implementation of the @CompileTimeConstant checker cannot reason about more
* complex scenarios, for example, returning compile-time-constant values from a method, or storing
* compile-time-constant values in a collection. APIs will typically accommodate such use cases via
* domain-specific types that capture domain-specific aspects of trustworthiness that arise from
* values being under application control.
*/
@Documented
@Retention(CLASS)
@Target({ElementType.PARAMETER, ElementType.FIELD})
public @interface CompileTimeConstant {}