DummyArrayWriter (Drill : 1.19.0 API)

java.lang.Object
- org.apache.drill.exec.vector.accessor.writer.AbstractArrayWriter
- - org.apache.drill.exec.vector.accessor.writer.dummy.DummyArrayWriter

All Implemented Interfaces:

ArrayWriter, ColumnWriter, WriterEvents, WriterPosition

Direct Known Subclasses:

DummyDictWriter
```
public class DummyArrayWriter
extends AbstractArrayWriter
```
Dummy scalar array writer that allows a client to write values into the array, but discards all of them. Provides no implementations of any methods, all are simply ignored.
Experience may suggest that some methods must return non-dummy values, such as the number of items in the array. That can be added as needed.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class DummyArrayWriter.DummyOffsetVectorWriter
- Nested classes/interfaces inherited from class org.apache.drill.exec.vector.accessor.writer.AbstractArrayWriter
  AbstractArrayWriter.ArrayElementWriterIndex, AbstractArrayWriter.ArrayObjectWriter, AbstractArrayWriter.BaseArrayWriter
- Nested classes/interfaces inherited from interface org.apache.drill.exec.vector.accessor.writer.WriterEvents
  WriterEvents.ColumnWriterListener, WriterEvents.State

Nested Classes
Modifier and Type	Class and Description
`static class`	`DummyArrayWriter.DummyOffsetVectorWriter`

Field Summary

Fields
Modifier and Type Field and Description

static DummyArrayWriter.DummyOffsetVectorWriter offsetVectorWriter
- Fields inherited from class org.apache.drill.exec.vector.accessor.writer.AbstractArrayWriter
  elementIndex, elementObjWriter, offsetsWriter, outerIndex

Fields
Modifier and Type	Field and Description
`static DummyArrayWriter.DummyOffsetVectorWriter`	`offsetVectorWriter`

Constructor Summary

Constructors
Constructor and Description

DummyArrayWriter(ColumnMetadata schema, AbstractObjectWriter elementWriter)

Constructors
Constructor and Description
`DummyArrayWriter(ColumnMetadata schema, AbstractObjectWriter elementWriter)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`bindIndex(ColumnWriterIndex index)` Bind the writer to a writer index.
`void`	`copy(ColumnReader from)` Copy a single value from the given reader, which must be of the same type as this writer.
`void`	`endArrayValue()` End a value.
`void`	`endWrite()` End a batch: finalize any vector values.
`boolean`	`isProjected()` Whether this writer is projected (is backed by a materialized vector), or is unprojected (is just a dummy writer.) In most cases, clients can ignore whether the column is projected and just write to the writer.
`int`	`lastWriteIndex()` Return the last write position in the vector.
`void`	`postRollover()` The vectors backing this writer rolled over.
`void`	`preRollover()` The vectors backing this vector are about to roll over.
`void`	`restartRow()` During a writer to a row, rewind the the current index position to restart the row.
`void`	`save()` When the array contains a tuple or an array, call `save()` after each array value.
`void`	`saveRow()` Saves a row.
`void`	`setObject(Object array)` Generic technique to write data as a generic Java object.
`void`	`startRow()` Start a new row.
`void`	`startWrite()` Start a write (batch) operation.

Methods inherited from class org.apache.drill.exec.vector.accessor.writer.AbstractArrayWriter
array, bindListener, dict, dump, entry, entryType, nullable, offsetWriter, rowStartIndex, scalar, schema, setNull, setNull, size, tuple, type, variant, writeIndex

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

- Field Detail
  - offsetVectorWriter
```
public static final DummyArrayWriter.DummyOffsetVectorWriter offsetVectorWriter
```
- Constructor Detail
  - DummyArrayWriter
```
public DummyArrayWriter(ColumnMetadata schema,
                        AbstractObjectWriter elementWriter)
```
- Method Detail
  - save
```
public void save()
```
    Description copied from interface: ArrayWriter
    
    When the array contains a tuple or an array, call save() after each array value. Not necessary when writing scalars; each set operation calls save automatically.
  - setObject
```
public void setObject(Object array)
```
    Description copied from interface: ColumnWriter
    Generic technique to write data as a generic Java object. The type of the object must match the target writer. Primarily for testing.
    - Scalar: The type of the Java object must match the type of the target vector. String or byte[] can be used for Varchar vectors.
    - Array: Write the array given an array of values. The object must be a Java array. The type of the array must match the type of element in the repeated vector. That is, if the vector is a Repeated Int, provide an int[] array.
    - Tuple (map or row): The Java object must be an array of objects in which the members of the array have a 1:1 correspondence with the members of the tuple in the order defined by the writer metadata. That is, if the map is (Int, Varchar), provide a Object[] array like this: {10, "fred"}.
    - Union: Uses the Java object type to determine the type of the backing vector. Creates a vector of the required type if needed.
    Parameters:
    
    array - value to write to the vector. The Java type of the object indicates the Drill storage type
  - startWrite
```
public void startWrite()
```
    Description copied from interface: WriterEvents
    
    Start a write (batch) operation. Performs any vector initialization required at the start of a batch (especially for offset vectors.)
  - startRow
```
public void startRow()
```
    Description copied from interface: WriterEvents
    
    Start a new row. To be called only when a row is not active. To restart a row, call WriterEvents.restartRow() instead.
  - endArrayValue
```
public void endArrayValue()
```
    Description copied from interface: WriterEvents
    
    End a value. Similar to WriterEvents.saveRow(), but the save of a value is conditional on saving the row. This version is primarily of use in tuples nested inside arrays: it saves each tuple within the array, advancing to a new position in the array. The update of the array's offset vector based on the cumulative value saves is done when saving the row.
  - restartRow
```
public void restartRow()
```
    Description copied from interface: WriterEvents
    
    During a writer to a row, rewind the the current index position to restart the row. Done when abandoning the current row, such as when filtering out a row at read time.
  - saveRow
```
public void saveRow()
```
    Description copied from interface: WriterEvents
    
    Saves a row. Commits offset vector locations and advances each to the next position. Can be called only when a row is active.
  - endWrite
```
public void endWrite()
```
    Description copied from interface: WriterEvents
    
    End a batch: finalize any vector values.
  - preRollover
```
public void preRollover()
```
    Description copied from interface: WriterEvents
    
    The vectors backing this vector are about to roll over. Finish the current batch up to, but not including, the current row.
  - postRollover
```
public void postRollover()
```
    Description copied from interface: WriterEvents
    
    The vectors backing this writer rolled over. This means that data for the current row has been rolled over into a new vector. Offsets and indexes should be shifted based on the understanding that data for the current row now resides at the start of a new vector instead of its previous location elsewhere in an old vector.
  - lastWriteIndex
```
public int lastWriteIndex()
```
    Description copied from interface: WriterPosition
    
    Return the last write position in the vector. This may be the same as the writer index position (if the vector was written at that point), or an earlier point. In either case, this value points to the last valid value in the vector.
    
    Specified by:
    
    lastWriteIndex in interface WriterPosition
    
    Overrides:
    
    lastWriteIndex in class AbstractArrayWriter
    
    Returns:
    
    index of the last valid value in the vector
  - bindIndex
```
public void bindIndex(ColumnWriterIndex index)
```
    Description copied from interface: WriterEvents
    
    Bind the writer to a writer index.
    
    Parameters:
    
    index - the writer index (top level or nested for arrays)
  - isProjected
```
public boolean isProjected()
```
    Description copied from interface: ColumnWriter
    
    Whether this writer is projected (is backed by a materialized vector), or is unprojected (is just a dummy writer.) In most cases, clients can ignore whether the column is projected and just write to the writer. This flag handles those special cases where it is helpful to know if the column is projected or not.
    
    Specified by:
    
    isProjected in interface ColumnWriter
    
    Overrides:
    
    isProjected in class AbstractArrayWriter
  - copy
```
public void copy(ColumnReader from)
```
    Description copied from interface: ColumnWriter
    
    Copy a single value from the given reader, which must be of the same type as this writer.
    
    Specified by:
    
    copy in interface ColumnWriter
    
    Overrides:
    
    copy in class AbstractArrayWriter
    
    Parameters:
    
    from - reader to provide the data

Class DummyArrayWriter

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.drill.exec.vector.accessor.writer.AbstractArrayWriter

Nested classes/interfaces inherited from interface org.apache.drill.exec.vector.accessor.writer.WriterEvents

Field Summary

Fields inherited from class org.apache.drill.exec.vector.accessor.writer.AbstractArrayWriter

Constructor Summary

Method Summary

Methods inherited from class org.apache.drill.exec.vector.accessor.writer.AbstractArrayWriter

Methods inherited from class java.lang.Object

Field Detail

offsetVectorWriter

Constructor Detail

DummyArrayWriter

Method Detail

save

setObject

startWrite

startRow

endArrayValue

restartRow

saveRow

endWrite

preRollover

postRollover

lastWriteIndex

bindIndex

isProjected

copy