package detective.common.annotation; 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; /** * The class to which this annotation is applied is immutable. This means that * its state cannot be seen to change by callers, which implies that * <ul> * <li> all public fields are final, </li> * <li> all public final reference fields refer to other immutable objects, and </li> * <li> constructors and methods do not publish references to any internal state * which is potentially mutable by the implementation. </li> * </ul> * Immutable objects may still have internal mutable state for purposes of performance * optimization; some state variables may be lazily computed, so long as they are computed * from immutable state and that callers cannot tell the difference. * <p> * Immutable objects are inherently thread-safe; they may be passed between threads or * published without synchronization. * <p> * Based on code developed by Brian Goetz and Tim Peierls and concepts * published in 'Java Concurrency in Practice' by Brian Goetz, Tim Peierls, * Joshua Bloch, Joseph Bowbeer, David Holmes and Doug Lea. */ @Documented @Target(ElementType.TYPE) @Retention(RetentionPolicy.CLASS) // The original version used RUNTIME public @interface Immutable { }