Holder (Apache Calcite API)

java.lang.Object
- org.apache.calcite.util.Holder<E>

Type Parameters:

E - Element type
```
public class Holder<E>
extends java.lang.Object
```
A mutable slot that can contain one object.
A holder is useful for implementing OUT or IN-OUT parameters.

It is possible to sub-class to receive events on get or set.

Field Summary

Fields
Modifier and Type Field Description

private E e

Constructor Summary

Constructors
Modifier Constructor Description

protected Holder(E e)
Creates a Holder containing a given value.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`E`	`get()`	Gets the value.
`static <E> Holder<E>`	`of(E e)`	Creates a holder containing a given value.
`void`	`set(E e)`	Sets the value.

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

- Field Detail
  - e
```
private E e
```
- Constructor Detail
  - Holder
```
protected Holder(E e)
```
    Creates a Holder containing a given value.
    Call this method from a derived constructor or via the of(E) method.
- Method Detail
  - set
```
public void set(E e)
```
    Sets the value.
  - get
```
public E get()
```
    Gets the value.
  - of
```
public static <E> Holder<E> of(E e)
```
    Creates a holder containing a given value.