com.oracle.truffle.api.interop

Class KeyInfo

java.lang.Object

com.oracle.truffle.api.interop.KeyInfo

public final class KeyInfo
extends Object

This class represents key info bit flags. Use this class as a utility to get or set the bit flags when dealing with Message.KEY_INFO message.

The bit flags have following meaning:

• 0. bit: Existence of the key
• 1. bit: Readability of the key (Message.READ is supported)
• 2. bit: Writability of the key (Message.WRITE is supported)
• 3. bit: Invocability of the key (Message.createInvoke(int) is supported)
• 4. bit: Internal attribute of the key (see an internal argument to Message.KEYS)

When a readable or writable flag is true, it does not necessarily guarantee that subsequent Message.READ or Message.WRITE message will succeed. Read or write can fail due to some momentary bad state. An object field is expected not to be readable resp. writable when it's known that the field can not be read (e.g. a bean property without a getter) resp. can not be written to (e.g. a bean property without a setter). The same applies to invocable flag and invoke message.

When the key does not exist (0. bit is zero), then all other bits must be zero as well.

Since:

0.26

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	KeyInfo.Builder A builder of bit flags.

Method Summary

Modifier and Type	Method and Description
static boolean	isExisting(int infoBits) Test if the bits represent an existing key.
static boolean	isInternal(int infoBits) Test if internal flag is on.
static boolean	isInvocable(int infoBits) Test if invocable flag is on.
static boolean	isReadable(int infoBits) Test if readable flag is on.
static boolean	isWritable(int infoBits) Test if writable flag is on.
static KeyInfo.Builder	newBuilder() Create a new bit flags builder.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

newBuilder

public static KeyInfo.Builder newBuilder()

Create a new bit flags builder. The builder is reusable and builds key info of existing keys only. Use 0 directly to inform about a non-existing key.

Since:

0.26

isExisting

public static boolean isExisting(int infoBits)

Test if the bits represent an existing key.

Since:

0.26

isReadable

public static boolean isReadable(int infoBits)

Test if readable flag is on.

Since:

0.26

isWritable

public static boolean isWritable(int infoBits)

Test if writable flag is on.

Since:

0.26

isInvocable

public static boolean isInvocable(int infoBits)

Test if invocable flag is on.

Since:

0.26

isInternal

public static boolean isInternal(int infoBits)

Test if internal flag is on.

Since:

0.26