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:
- KeyInfo.READABLE: if reading an existing key is supported.
- KeyInfo.MODIFIABLE: if writing an existing key is supported.
- KeyInfo.INSERTABLE if writing a new key is supported.
- KeyInfo.INVOCABLE: if invoking an existing key is supported.
- KeyInfo.REMOVABLE if removing an existing key is supported.
- KeyInfo.INTERNAL if an existing key is internal.
- KeyInfo.READ_SIDE_EFFECTS if Message.READ of the key value may have side-effects, i.e. may change values of some keys, state of objects, etc.
- KeyInfo.WRITE_SIDE_EFFECTS if Message.WRITE of the key value may have side-effects, i.e. may change values of other keys, state of other objects, etc.
  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 Message.INVOKE message.
Since:

0.26

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`INSERTABLE` Single bit that is set if `writing` a new key is supported.
`static int`	`INTERNAL` Single bit that is set if an existing key is internal.
`static int`	`INVOCABLE` Single bit that is set if `invoking` an existing key is supported.
`static int`	`MODIFIABLE` Single bit that is set if `writing` an existing key is supported.
`static int`	`NONE` Value of the key info if the key has no capability.
`static int`	`READ_SIDE_EFFECTS` Single bit that is set if `Message.READ` may have side-effects.
`static int`	`READABLE` Single bit that is set if `reading` an existing key is supported.
`static int`	`REMOVABLE` Single bit that is set if `removing` an existing key is supported.
`static int`	`WRITE_SIDE_EFFECTS` Single bit that is set if `Message.WRITE` may have side-effects.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static boolean`	`hasReadSideEffects(int infoBits)` Test if `Message.READ` may have side-effects.
`static boolean`	`hasWriteSideEffects(int infoBits)` Test if `Message.WRITE` may have side-effects.
`static boolean`	`isExisting(int infoBits)` Test if the bits represent an existing key.
`static boolean`	`isInsertable(int infoBits)` Test if `writing` a new key is supported.
`static boolean`	`isInternal(int infoBits)` Test if an existing key is internal.
`static boolean`	`isInvocable(int infoBits)` Test if `invoking` an existing key is supported.
`static boolean`	`isModifiable(int infoBits)` Test if `writing` an existing key is supported.
`static boolean`	`isReadable(int infoBits)` Test if `reading` an existing key is supported.
`static boolean`	`isRemovable(int infoBits)` Test if `writing` a new key is supported.
`static boolean`	`isWritable(int infoBits)` Test if `writing` an existing or new key is supported.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - NONE
```
public static final int NONE
```
    Value of the key info if the key has no capability.
    
    Since:
    
    0.33
    
    See Also:
    
    Constant Field Values
  - READABLE
```
public static final int READABLE
```
    Single bit that is set if reading an existing key is supported.
    
    Since:
    
    0.33
    
    See Also:
    
    KeyInfo.READ_SIDE_EFFECTS, Constant Field Values
  - MODIFIABLE
```
public static final int MODIFIABLE
```
    Single bit that is set if writing an existing key is supported.
    
    Since:
    
    0.33
    
    See Also:
    
    KeyInfo.WRITE_SIDE_EFFECTS, Constant Field Values
  - INVOCABLE
```
public static final int INVOCABLE
```
    Single bit that is set if invoking an existing key is supported.
    
    Since:
    
    0.33
    
    See Also:
    
    Constant Field Values
  - INTERNAL
```
public static final int INTERNAL
```
    Single bit that is set if an existing key is internal.
    
    Since:
    
    0.33
    
    See Also:
    
    Constant Field Values
  - REMOVABLE
```
public static final int REMOVABLE
```
    Single bit that is set if removing an existing key is supported.
    
    Since:
    
    0.33
    
    See Also:
    
    Constant Field Values
  - INSERTABLE
```
public static final int INSERTABLE
```
    Single bit that is set if writing a new key is supported.
    
    Since:
    
    0.33
    
    See Also:
    
    Constant Field Values
  - READ_SIDE_EFFECTS
```
public static final int READ_SIDE_EFFECTS
```
    Single bit that is set if Message.READ may have side-effects. A read side-effect means any change in runtime state that is observable by the guest language program. For instance in JavaScript a property Message.READ may have side-effects if the property has a getter function.
    
    Since:
    
    1.0
    
    See Also:
    
    Constant Field Values
  - WRITE_SIDE_EFFECTS
```
public static final int WRITE_SIDE_EFFECTS
```
    Single bit that is set if Message.WRITE may have side-effects. A write side-effect means any change in runtime state, besides the write operation of the member, that is observable by the guest language program. For instance in JavaScript a property Message.WRITE may have side-effects if the property has a setter function.
    
    Since:
    
    1.0
    
    See Also:
    
    Constant Field Values
- Method Detail
  - 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 reading an existing key is supported.
    
    Since:
    
    0.26
  - isWritable
```
public static boolean isWritable(int infoBits)
```
    Test if writing an existing or new key is supported.
    
    Since:
    
    0.26
  - hasReadSideEffects
```
public static boolean hasReadSideEffects(int infoBits)
```
    Test if Message.READ may have side-effects.
    
    Since:
    
    1.0
  - hasWriteSideEffects
```
public static boolean hasWriteSideEffects(int infoBits)
```
    Test if Message.WRITE may have side-effects.
    
    Since:
    
    1.0
  - isInvocable
```
public static boolean isInvocable(int infoBits)
```
    Test if invoking an existing key is supported.
    
    Since:
    
    0.26
  - isInternal
```
public static boolean isInternal(int infoBits)
```
    Test if an existing key is internal.
    
    Since:
    
    0.26
  - isRemovable
```
public static boolean isRemovable(int infoBits)
```
    Test if writing a new key is supported.
    
    Since:
    
    0.33
  - isModifiable
```
public static boolean isModifiable(int infoBits)
```
    Test if writing an existing key is supported.
    
    Since:
    
    0.33
  - isInsertable
```
public static boolean isInsertable(int infoBits)
```
    Test if writing a new key is supported.
    
    Since:
    
    0.33

Class KeyInfo

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

NONE

READABLE

MODIFIABLE

INVOCABLE

INTERNAL

REMOVABLE

INSERTABLE

READ_SIDE_EFFECTS

WRITE_SIDE_EFFECTS

Method Detail

isExisting

isReadable

isWritable

hasReadSideEffects

hasWriteSideEffects

isInvocable

isInternal

isRemovable

isModifiable

isInsertable