Snippet.Status (Java SE 15 & JDK 15) (original) (raw)

All Implemented Interfaces:

[Serializable](../../../java.base/java/io/Serializable.html "interface in java.io"), [Comparable](../../../java.base/java/lang/Comparable.html "interface in java.lang")<[Snippet.Status](Snippet.Status.html "enum in jdk.jshell")>, [Constable](../../../java.base/java/lang/constant/Constable.html "interface in java.lang.constant")

Enclosing class:

Snippet

public static enum Snippet.Status extends Enum<Snippet.Status>

Describes the current state of a Snippet. This is a dynamic property of a Snippet within the JShell state -- thus is retrieved with a query on {@code JShell}.

The Status changes as the state changes. For example, creation of another snippet witheval may resolve dependencies of this Snippet (or invalidate those dependencies), oroverwrite this Snippet changing itsStatus.

Important properties associated with Status are:isDefined(), if it is visible to other existing and new snippets; andisActive(), if, as the JShell state changes, the snippet will update, possibly changing Status. An executable Snippet can only be executed if it is in the theVALID Status.

See Also:

JShell.status(jdk.jshell.Snippet)

• Nested Class Summary

• Enum Constant Summary

Enum Constants

• Method Summary

Methods declared in class java.lang.Enum

[clone](../../../java.base/java/lang/Enum.html#clone%28%29), [compareTo](../../../java.base/java/lang/Enum.html#compareTo%28E%29), [describeConstable](../../../java.base/java/lang/Enum.html#describeConstable%28%29), [equals](../../../java.base/java/lang/Enum.html#equals%28java.lang.Object%29), [finalize](../../../java.base/java/lang/Enum.html#finalize%28%29), [getDeclaringClass](../../../java.base/java/lang/Enum.html#getDeclaringClass%28%29), [hashCode](../../../java.base/java/lang/Enum.html#hashCode%28%29), [name](../../../java.base/java/lang/Enum.html#name%28%29), [ordinal](../../../java.base/java/lang/Enum.html#ordinal%28%29), [toString](../../../java.base/java/lang/Enum.html#toString%28%29), [valueOf](../../../java.base/java/lang/Enum.html#valueOf%28java.lang.Class,java.lang.String%29)

• Enum Constant Details

  • VALID

  The snippet is a valid snippet (in the context of current JShell state). Only snippets with VALID Status can be executed (though not allVALID snippets have executable code).
  The snippet is defined (isDefined() == true). If the snippet is a declaration or import (Snippet.Kind.isPersistent()), it is visible to other snippets
  The snippet will update as dependents change (isActive() == true), its status could become RECOVERABLE_DEFINED, RECOVERABLE_NOT_DEFINED,DROPPED, or OVERWRITTEN.

  • RECOVERABLE_DEFINED

  The snippet is a declaration snippet with potentially recoverable unresolved references or other issues in its body (in the context of current JShell state). Only a DeclarationSnippet can have thisStatus.
  The snippet has a valid signature and it is visible to other snippets (isDefined() == true) and thus can be referenced in existing or new snippets but the snippet cannot be executed. An UnresolvedReferenceException will be thrown on an attempt to execute it.
  The snippet will update as dependents change (isActive() == true), its status could become VALID, RECOVERABLE_NOT_DEFINED,DROPPED, or OVERWRITTEN.
  Note: both RECOVERABLE_DEFINED and RECOVERABLE_NOT_DEFINED indicate potentially recoverable errors, they differ in that, forRECOVERABLE_DEFINED, the snippet isdefined.

  • RECOVERABLE_NOT_DEFINED

  public static final Snippet.Status RECOVERABLE_NOT_DEFINED
  The snippet is a declaration snippet with potentially recoverable unresolved references or other issues (in the context of current JShell state). Only a DeclarationSnippet can have thisStatus.
  The snippet has an invalid signature or the implementation is otherwise unable to define it. The snippet it is not visible to other snippets (isDefined() == false) and thus cannot be referenced or executed.
  The snippet will update as dependents change (isActive() == true), its status could become VALID, RECOVERABLE_DEFINED,DROPPED, or OVERWRITTEN.
  Note: both RECOVERABLE_DEFINED and RECOVERABLE_NOT_DEFINED indicate potentially recoverable errors, they differ in that, forRECOVERABLE_DEFINED, the snippet isdefined.

  • DROPPED

  The snippet is inactive because of an explicit call to the JShell.drop(Snippet).
  The snippet is not visible to other snippets (isDefined() == false) and thus cannot be referenced or executed.
  The snippet will not update as dependents change (isActive() == false), itsStatus will never change again.

  • OVERWRITTEN

  The snippet is inactive because it has been replaced by a new snippet. This occurs when the new snippet added witheval matches a previous snippet. A TypeDeclSnippet will match anotherTypeDeclSnippet if the names match. For example class X { } will overwriteclass X { int ii; } orinterface X { }. A MethodSnippet will match anotherMethodSnippet if the names and parameter types match. For example void m(int a) { } will overwriteint m(int a) { return a+a; }. A VarSnippet will match anotherVarSnippet if the names match. For example double z; will overwritelong z = 2L;. Only a PersistentSnippet can have thisStatus.
  The snippet is not visible to other snippets (isDefined() == false) and thus cannot be referenced or executed.
  The snippet will not update as dependents change (isActive() == false), itsStatus will never change again.

  • REJECTED

  The snippet is inactive because it failed compilation on initial evaluation and it is not capable of becoming valid with further changes to the JShell state.
  The snippet is not visible to other snippets (isDefined() == false) and thus cannot be referenced or executed.
  The snippet will not update as dependents change (isActive() == false), itsStatus will never change again.

  • NONEXISTENT

  The snippet is inactive because it does not yet exist. Used only in SnippetEvent.previousStatus for new snippets.JShell.status(Snippet) will never return this Status.
  Vacuously, isDefined() andisActive() are both defined false.

• Method Details

  • values

  Returns an array containing the constants of this enum type, in the order they are declared.
  Returns:
  an array containing the constants of this enum type, in the order they are declared

  • valueOf

  Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
  Parameters:
  name - the name of the enum constant to be returned.
  Returns:
  the enum constant with the specified name
  Throws:
  [IllegalArgumentException](../../../java.base/java/lang/IllegalArgumentException.html "class in java.lang") - if this enum type has no constant with the specified name
  [NullPointerException](../../../java.base/java/lang/NullPointerException.html "class in java.lang") - if the argument is null

  • isActive

  public boolean isActive()
  Indicates whether the Snippet is active, that is, will a persistent snippet be re-evaluated when a newJShell.eval(String) orJShell.drop(Snippet) that could change its status is invoked. This is more broad thanisDefined() since a Snippet which isRECOVERABLE_NOT_DEFINED will be updated.
  Returns:
  true if the Snippet is active; otherwise false

  • isDefined

  public boolean isDefined()
  Indicates whether the snippet is currently part of the defined state of the JShell. Is it visible to compilation of other snippets?
  Returns:
  true if the Snippet is defined; otherwisefalse