Scan

Type Parameters:

ThisT - the child Java API class, returned by method chaining

T - the Java type of tasks produces by this scan

G - the Java type of task groups produces by this scan

All Known Subinterfaces:

BatchScan, IncrementalAppendScan, IncrementalChangelogScan, IncrementalScan<ThisT,T,G>, TableScan

All Known Implementing Classes:

AllDataFilesTable.AllDataFilesTableScan, AllDeleteFilesTable.AllDeleteFilesTableScan, AllFilesTable.AllFilesTableScan, AllManifestsTable.AllManifestsTableScan, DataFilesTable.DataFilesTableScan, DataTableScan, DeleteFilesTable.DeleteFilesTableScan, FilesTable.FilesTableScan
```
public interface Scan<ThisT,T extends ScanTask,G extends ScanTaskGroup<T>>
```
Scan objects are immutable and can be shared between threads. Refinement methods, like select(Collection) and filter(Expression), create new TableScan instances.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`ThisT`	`caseSensitive(boolean caseSensitive)` Create a new scan from this that, if data columns where selected via `select(java.util.Collection)`, controls whether the match to the schema will be done with case sensitivity.
`Expression`	`filter()` Returns this scan's filter `Expression`.
`ThisT`	`filter(Expression expr)` Create a new scan from the results of this filtered by the `Expression`.
`ThisT`	`ignoreResiduals()` Create a new scan from this that applies data filtering to files but not to rows in those files.
`ThisT`	`includeColumnStats()` Create a new scan from this that loads the column stats with each data file.
`boolean`	`isCaseSensitive()` Returns whether this scan is case-sensitive with respect to column names.
`ThisT`	`option(java.lang.String property, java.lang.String value)` Create a new scan from this scan's configuration that will override the `Table`'s behavior based on the incoming pair.
`CloseableIterable<T>`	`planFiles()` Plan tasks for this scan where each task reads a single file.
`CloseableIterable<G>`	`planTasks()` Plan balanced task groups for this scan by splitting large and combining small tasks.
`ThisT`	`planWith(java.util.concurrent.ExecutorService executorService)` Create a new scan to use a particular executor to plan.
`ThisT`	`project(Schema schema)` Create a new scan from this with the schema as its projection.
`Schema`	`schema()` Returns this scan's projection `Schema`.
`ThisT`	`select(java.util.Collection<java.lang.String> columns)` Create a new scan from this that will read the given data columns.
`default ThisT`	`select(java.lang.String... columns)` Create a new scan from this that will read the given columns.
`int`	`splitLookback()` Returns the split lookback for this scan.
`long`	`splitOpenFileCost()` Returns the split open file cost for this scan.
`long`	`targetSplitSize()` Returns the target split size for this scan.

- Method Detail
  - option
```
ThisT option(java.lang.String property,
             java.lang.String value)
```
    Create a new scan from this scan's configuration that will override the Table's behavior based on the incoming pair. Unknown properties will be ignored.
    
    Parameters:
    
    property - name of the table property to be overridden
    
    value - value to override with
    
    Returns:
    
    a new scan based on this with overridden behavior
  - project
```
ThisT project(Schema schema)
```
    Create a new scan from this with the schema as its projection.
    
    Parameters:
    
    schema - a projection schema
    
    Returns:
    
    a new scan based on this with the given projection
  - caseSensitive
```
ThisT caseSensitive(boolean caseSensitive)
```
    Create a new scan from this that, if data columns where selected via select(java.util.Collection), controls whether the match to the schema will be done with case sensitivity. Default is true.
    
    Returns:
    
    a new scan based on this with case sensitivity as stated
  - isCaseSensitive
```
boolean isCaseSensitive()
```
    Returns whether this scan is case-sensitive with respect to column names.
    
    Returns:
    
    true if case-sensitive, false otherwise.
  - includeColumnStats
```
ThisT includeColumnStats()
```
    Create a new scan from this that loads the column stats with each data file.
    Column stats include: value count, null value count, lower bounds, and upper bounds.
    
    Returns:
    
    a new scan based on this that loads column stats.
  - select
```
ThisT select(java.util.Collection<java.lang.String> columns)
```
    Create a new scan from this that will read the given data columns. This produces an expected schema that includes all fields that are either selected or used by this scan's filter expression.
    
    Parameters:
    
    columns - column names from the table's schema
    
    Returns:
    
    a new scan based on this with the given projection columns
  - select
```
default ThisT select(java.lang.String... columns)
```
    Create a new scan from this that will read the given columns. This produces an expected schema that includes all fields that are either selected or used by this scan's filter expression.
    
    Parameters:
    
    columns - column names
    
    Returns:
    
    a new scan based on this with the given projection columns
  - filter
```
ThisT filter(Expression expr)
```
    Create a new scan from the results of this filtered by the Expression.
    
    Parameters:
    
    expr - a filter expression
    
    Returns:
    
    a new scan based on this with results filtered by the expression
  - filter
```
Expression filter()
```
    Returns this scan's filter Expression.
    
    Returns:
    
    this scan's filter expression
  - ignoreResiduals
```
ThisT ignoreResiduals()
```
    Create a new scan from this that applies data filtering to files but not to rows in those files.
    
    Returns:
    
    a new scan based on this that does not filter rows in files.
  - planWith
```
ThisT planWith(java.util.concurrent.ExecutorService executorService)
```
    Create a new scan to use a particular executor to plan. The default worker pool will be used by default.
    
    Parameters:
    
    executorService - the provided executor
    
    Returns:
    
    a table scan that uses the provided executor to access manifests
  - schema
```
Schema schema()
```
    Returns this scan's projection Schema.
    If the projection schema was set directly using project(Schema), returns that schema.
    If the projection schema was set by calling select(Collection), returns a projection schema that includes the selected data fields and any fields used in the filter expression.
    
    Returns:
    
    this scan's projection schema
  - planFiles
```
CloseableIterable<T> planFiles()
```
    Plan tasks for this scan where each task reads a single file.
    Use planTasks() for planning balanced tasks where each task will read either a single file, a part of a file, or multiple files.
    
    Returns:
    
    an Iterable of tasks scanning entire files required by this scan
  - planTasks
```
CloseableIterable<G> planTasks()
```
    Plan balanced task groups for this scan by splitting large and combining small tasks.
    Task groups created by this method may read partial input files, multiple input files or both.
    
    Returns:
    
    an Iterable of balanced task groups required by this scan
  - targetSplitSize
```
long targetSplitSize()
```
    Returns the target split size for this scan.
  - splitLookback
```
int splitLookback()
```
    Returns the split lookback for this scan.
  - splitOpenFileCost
```
long splitOpenFileCost()
```
    Returns the split open file cost for this scan.

Interface Scan<ThisT,T extends ScanTask,G extends ScanTaskGroup<T>>

Method Summary

Method Detail

option

project

caseSensitive

isCaseSensitive

includeColumnStats

select

select

filter

filter

ignoreResiduals

planWith

schema

planFiles

planTasks

targetSplitSize

splitLookback

splitOpenFileCost