org.checkerframework.checker.index.qual.IndexFor Maven / Gradle / Ivy
package org.checkerframework.checker.index.qual;
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;
/**
* An integer that can be used to index any of the given sequences.
*
* For example, an expression with type {@code @IndexFor({"a", "b"})} is non-negative and is less
* than both {@code a.length} and {@code b.length}. The sequences {@code a} and {@code b} might have
* different lengths.
*
*
The
* {@code String.charAt(int)} method is declared as
*
*
{@code
* class String {
* char charAt(@IndexFor("this") index) { ... }
* }
* }
*
* Writing {@code @IndexFor("arr")} is equivalent to writing {@link NonNegative @NonNegative}
* {@link LTLengthOf @LTLengthOf("arr")}, and that is how it is treated internally by the checker.
* Thus, if you write an {@code @IndexFor("arr")} annotation, you might see warnings about
* {@code @NonNegative} or {@code @LTLengthOf}.
*
* @see NonNegative
* @see LTLengthOf
* @checker_framework.manual #index-checker Index Checker
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE_USE, ElementType.TYPE_PARAMETER})
public @interface IndexFor {
/** Sequences that the annotated expression is a valid index for. */
String[] value();
}