org.apache.drill.exec.record

Class BatchSchema

java.lang.Object

org.apache.drill.exec.record.BatchSchema

All Implemented Interfaces:

Iterable<MaterializedField>

public class BatchSchema
extends Object
implements Iterable<MaterializedField>

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BatchSchema.SelectionVectorMode

Constructor Summary

Constructors

Constructor and Description
BatchSchema(BatchSchema.SelectionVectorMode selectionVector, List<MaterializedField> fields)

Method Summary

Methods

Modifier and Type	Method and Description
BatchSchema	clone()
boolean	equals(Object obj)
MaterializedField	getColumn(int index)
int	getFieldCount()
BatchSchema.SelectionVectorMode	getSelectionVectorMode()
int	hashCode()
boolean	isEquivalent(BatchSchema other)
Iterator<MaterializedField>	iterator()
BatchSchema	merge(BatchSchema otherSchema) Merge two schema to produce a new, merged schema.
static SchemaBuilder	newBuilder()
String	toString()

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

BatchSchema

public BatchSchema(BatchSchema.SelectionVectorMode selectionVector,
           List<MaterializedField> fields)

Method Detail

newBuilder

public static SchemaBuilder newBuilder()

getFieldCount

public int getFieldCount()

getColumn

public MaterializedField getColumn(int index)

iterator

public Iterator<MaterializedField> iterator()

Specified by:

iterator in interface Iterable<MaterializedField>

getSelectionVectorMode

public BatchSchema.SelectionVectorMode getSelectionVectorMode()

clone

public BatchSchema clone()

Overrides:

clone in class Object

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

isEquivalent

public boolean isEquivalent(BatchSchema other)

merge

public BatchSchema merge(BatchSchema otherSchema)

Merge two schema to produce a new, merged schema. The caller is responsible for ensuring that column names are unique. The order of the fields in the new schema is the same as that of this schema, with the other schema's fields appended in the order defined in the other schema.

Merging data with selection vectors is unlikely to be useful, or work well. With a selection vector, the two record batches would have to be correlated both in their selection vectors AND in the underlying vectors. Such a use case is hard to imagine. So, for now, this method forbids merging schemas if either of them carry a selection vector. If we discover a meaningful use case, we can revisit the issue.

Parameters:

otherSchema - the schema to merge with this one

Returns:

the new, merged, schema