EnumerableDefaults.MergeJoinEnumerator (Apache Calcite API)

java.lang.Object
- org.apache.calcite.linq4j.EnumerableDefaults.MergeJoinEnumerator<TResult,TSource,TInner,TKey>

Type Parameters:

TResult - result type

TSource - left input record type

TKey - key type

TInner - right input record type

All Implemented Interfaces:

AutoCloseable, Enumerator<TResult>

Enclosing class:

EnumerableDefaults
```
private static class EnumerableDefaults.MergeJoinEnumerator<TResult,TSource,TInner,TKey extends Comparable<TKey>>
extends Object
implements Enumerator<TResult>
```
Enumerator that performs a merge join on its sorted inputs.

Field Summary

Fields
Modifier and Type	Field and Description
`(package private) Enumerator<List<Object>>`	`cartesians`
`(package private) boolean`	`done`
`private Function1<TInner,TKey>`	`innerKeySelector`
`private Enumerator<TSource>`	`leftEnumerator`
`(package private) List<TSource>`	`lefts`
`private Function1<TSource,TKey>`	`outerKeySelector`
`private Function2<TSource,TInner,TResult>`	`resultSelector`
`private Enumerator<TInner>`	`rightEnumerator`
`(package private) List<TInner>`	`rights`

Constructor Summary

Constructors
Constructor and Description
`MergeJoinEnumerator(Enumerator<TSource> leftEnumerator, Enumerator<TInner> rightEnumerator, Function1<TSource,TKey> outerKeySelector, Function1<TInner,TKey> innerKeySelector, Function2<TSource,TInner,TResult> resultSelector)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`private boolean`	`advance()` Moves to the next key that is present in both sides.
`void`	`close()` Closes this enumerable and releases resources.
`TResult`	`current()` Gets the current element in the collection.
`boolean`	`moveNext()` Advances the enumerator to the next element of the collection.
`void`	`reset()` Sets the enumerator to its initial position, which is before the first element in the collection.
`private void`	`start()`

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

- Field Detail
  - lefts
```
final List<TSource> lefts
```
  - rights
```
final List<TInner> rights
```
  - leftEnumerator
```
private final Enumerator<TSource> leftEnumerator
```
  - rightEnumerator
```
private final Enumerator<TInner> rightEnumerator
```
  - outerKeySelector
```
private final Function1<TSource,TKey extends Comparable<TKey>> outerKeySelector
```
  - innerKeySelector
```
private final Function1<TInner,TKey extends Comparable<TKey>> innerKeySelector
```
  - resultSelector
```
private final Function2<TSource,TInner,TResult> resultSelector
```
  - done
```
boolean done
```
  - cartesians
```
Enumerator<List<Object>> cartesians
```
- Constructor Detail
  - MergeJoinEnumerator
```
MergeJoinEnumerator(Enumerator<TSource> leftEnumerator,
                    Enumerator<TInner> rightEnumerator,
                    Function1<TSource,TKey> outerKeySelector,
                    Function1<TInner,TKey> innerKeySelector,
                    Function2<TSource,TInner,TResult> resultSelector)
```
- Method Detail
  - start
```
private void start()
```
  - advance
```
private boolean advance()
```
    Moves to the next key that is present in both sides. Populates lefts and rights with the rows. Restarts the cross-join enumerator.
  - current
```
public TResult current()
```
    Description copied from interface: Enumerator
    
    Gets the current element in the collection.
    After an enumerator is created or after the Enumerator.reset() method is called, the Enumerator.moveNext() method must be called to advance the enumerator to the first element of the collection before reading the value of the current property; otherwise, current is undefined.
    This method also throws NoSuchElementException if the last call to moveNext returned false, which indicates the end of the collection.
    This method does not move the position of the enumerator, and consecutive calls to current return the same object until either moveNext or reset is called.
    An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated. The next call to moveNext or reset may, at the discretion of the implementation, throw a ConcurrentModificationException. If the collection is modified between moveNext and current, current returns the element that it is set to, even if the enumerator is already invalidated.
    
    Specified by:
    
    current in interface Enumerator<TResult>
    
    Returns:
    
    Current element
  - moveNext
```
public boolean moveNext()
```
    Description copied from interface: Enumerator
    
    Advances the enumerator to the next element of the collection.
    After an enumerator is created or after the reset method is called, an enumerator is positioned before the first element of the collection, and the first call to the moveNext method moves the enumerator over the first element of the collection.
    If moveNext passes the end of the collection, the enumerator is positioned after the last element in the collection and moveNext returns false. When the enumerator is at this position, subsequent calls to moveNext also return false until #reset is called.
    An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated. The next call to moveNext or Enumerator.reset() may, at the discretion of the implementation, throw a ConcurrentModificationException.
    
    Specified by:
    
    moveNext in interface Enumerator<TResult>
    
    Returns:
    
    true if the enumerator was successfully advanced to the next element; false if the enumerator has passed the end of the collection
  - reset
```
public void reset()
```
    Description copied from interface: Enumerator
    
    Sets the enumerator to its initial position, which is before the first element in the collection.
    An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated. The next call to Enumerator.moveNext() or reset may, at the discretion of the implementation, throw a ConcurrentModificationException.
    This method is optional; it may throw UnsupportedOperationException.
    Notes to Implementers
    All calls to Reset must result in the same state for the enumerator. The preferred implementation is to move the enumerator to the beginning of the collection, before the first element. This invalidates the enumerator if the collection has been modified since the enumerator was created, which is consistent with Enumerator.moveNext() and Enumerator.current().
    
    Specified by:
    
    reset in interface Enumerator<TResult>
  - close
```
public void close()
```
    Description copied from interface: Enumerator
    
    Closes this enumerable and releases resources.
    This method is idempotent. Calling it multiple times has the same effect as calling it once.
    
    Specified by:
    
    close in interface AutoCloseable
    
    Specified by:
    
    close in interface Enumerator<TResult>

Class EnumerableDefaults.MergeJoinEnumerator<TResult,TSource,TInner,TKey extends Comparable<TKey>>

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

lefts

rights

leftEnumerator

rightEnumerator

outerKeySelector

innerKeySelector

resultSelector

done

cartesians

Constructor Detail

MergeJoinEnumerator

Method Detail

start

advance

current

moveNext

reset

close