Package org.apache.druid.catalog.model.table

Class ResolvedExternalTable

java.lang.Object

org.apache.druid.catalog.model.table.ResolvedExternalTable

public class ResolvedExternalTable
extends Object

Internal class to hold the intermediate form of an external table: the input source and input format properties converted to Java maps, and the types of each resolved to the corresponding definitions. Used to validate a table specification, and to convert a table specification to an ExternalTableSpec when used in SQL.

Field Summary

Fields

Modifier and Type	Field	Description
protected final Map<String,Object>	inputFormatMap
protected final Map<String,Object>	inputSourceMap

Constructor Summary

Constructors

Constructor	Description
ResolvedExternalTable(ResolvedTable table)	Construct a resolved external table by extracting the input source and input format properties, and converting each to a Java map.

Method Summary

Modifier and Type	Method	Description
ExternalTableSpec	convert()	Return the ExternalTableSpec for a catalog entry for a this object which must be a fully-defined table.
ResolvedExternalTable	resolve(TableDefnRegistry registry)	Look up the input source type and input format type to find the corresponding definitions in the table registry.
ResolvedTable	resolvedTable()
TableFunction	tableFn()	Return a table function definition for a partial table as given by this object.
void	validate(TableDefnRegistry registry)	Validate that the table spec is correct by resolving the definitions, then converting the JSON to the desired object type.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

inputSourceMap

protected final Map<String,Object> inputSourceMap

inputFormatMap

protected final Map<String,Object> inputFormatMap

Constructor Details

ResolvedExternalTable

public ResolvedExternalTable(ResolvedTable table)

Construct a resolved external table by extracting the input source and input format properties, and converting each to a Java map. Validates that the input source is present: the format is optional.

Note: does not resolve the input source and input format definitions: that is done as a separate step when needed.

Method Details

resolvedTable

public ResolvedTable resolvedTable()

resolve

public ResolvedExternalTable resolve(TableDefnRegistry registry)

Look up the input source type and input format type to find the corresponding definitions in the table registry. Throws an exception if the types are not defined. The input source is required, the format is optional.

Note, for resolution to work, the name of each definition must be the same as that used as the type key in the serialized JSON.

validate

public void validate(TableDefnRegistry registry)

Validate that the table spec is correct by resolving the definitions, then converting the JSON to the desired object type. Note that this path requires special handling: the table spec may be partial, which means it is missing information needed to create a complete input source. The input source definition defines which values can be omitted, and defined later in SQL via function parameters. If those values are missing, then the input source defn should provide dummy values so that the validation will succeed (assuming that the properties that are provided are valid.)

tableFn

public TableFunction tableFn()

Return a table function definition for a partial table as given by this object. The function defines parameters to gather the values needed to convert the partial table into a fully-defined table which can be converted to an ExternalTableSpec.

convert

public ExternalTableSpec convert()

Return the ExternalTableSpec for a catalog entry for a this object which must be a fully-defined table.