Collaboration diagram for com.cloudera.impala.analysis.Path:

Classes
enum	PathType

Public Member Functions
	Path (TupleDescriptor rootDesc, List< String > rawPath)

	Path (Table rootTable, List< String > rawPath)

	Path (Path rootPath, List< String > relRawPath)

boolean	resolve ()

Table	getRootTable ()

TupleDescriptor	getRootDesc ()

List< String >	getRawPath ()

boolean	isResolved ()

List< Type >	getMatchedTypes ()

List< Integer >	getMatchedPositions ()

boolean	hasNonDestCollection ()

String	getFirstCollectionName ()

Type	getFirstCollectionType ()

Type	destType ()

Table	destTable ()

Column	destColumn ()

TupleDescriptor	destTupleDesc ()

List< String >	getFullyQualifiedRawPath ()

List< Integer >	getAbsolutePath ()

String	toString ()

Static Public Member Functions
static StructType	getTypeAsStruct (Type t)

static ArrayList< String >	createRawPath (String rootAlias, String fieldName)

static Path	createRelPath (Path rootPath, String...fieldNames)

Static Public Attributes
static final String	ARRAY_ITEM_FIELD_NAME = "item"

static final String	ARRAY_POS_FIELD_NAME = "pos"

static final String	MAP_KEY_FIELD_NAME = "key"

static final String	MAP_VALUE_FIELD_NAME = "value"

Private Attributes
final List< String >	rawPath_

final TupleDescriptor	rootDesc_

final Table	rootTable_

final Path	rootPath_

final List< Type >	matchedTypes_ = Lists.newArrayList()

final List< Integer >	matchedPositions_ = Lists.newArrayList()

int	firstCollectionPathIdx_ = -1

int	firstCollectionTypeIdx_ = -1

boolean	isResolved_ = false

List< Integer >	absolutePath_ = null

Detailed Description

Represents a resolved or unresolved dot-separated path that is rooted at a registered tuple descriptor, catalog table/view, or an existing resolved path.

This class implements the resolution logic for mapping an implicit or explicit raw path to the corresponding physical types/positions in the schema tree.

Implicit vs. Explicit Paths The item of an array and the key/value of maps are accessed via their implicit field names. However, if the type of an array item or a map value is a struct, then we allow omitting the explicit reference to the struct type in paths for accessing fields within that struct as a shorthand for user convenience. An explicit reference to the struct type is always legal. Paths that explicitly reference such a struct are "physical" because they typically map exactly to the schema representation in the underlying storage format (e.g. Parquet/Avro). Paths that omit the struct reference are called "implicit". During resolution, explicit paths are always preferred over implicit paths for resolving ambiguities.

Example create table d.t ( c array<struct<f:int,item:int,pos:int>> );

select ... from d.t.c d.t.c <– resolves to type array<struct<f:int,item:int,pos:int>> c alias <– type struct<item:struct<f:int,item:int,pos:int>,pos:bigint>>

select c.item.f, c.f from d.t.c c.item.f <– explicit path to "f" c.f <– implicit path to "f", skips "item" reference (same for the unqualified versions item.f and f)

select c.item, c.item.item from d.t.c c.item <– explicit path to "item" struct of type struct<f:int,item:string> c.item.item <– explicit path to string "item"; there is no logical path to the string "item" due to the "item" name conflict c.pos <– explicit path to "pos" of type bigint c.item.pos <– explicit path to "pos" of type int; there is no logical path to the int "pos" due to the "pos" name conflict (same for unqualified versions item, item.item, pos, item.pos)

Please refer to TestImplicitAndExplicitPaths() for analogous examples for maps.

Definition at line 74 of file Path.java.

Constructor & Destructor Documentation

com.cloudera.impala.analysis.Path.Path	(	TupleDescriptor	rootDesc,
		List< String >	rawPath
	)

inline

Constructs a Path rooted at the given rootDesc.

Definition at line 122 of file Path.java.

References com.cloudera.impala.analysis.Path.rawPath_, com.cloudera.impala.analysis.Path.rootDesc_, com.cloudera.impala.analysis.Path.rootPath_, and com.cloudera.impala.analysis.Path.rootTable_.

Referenced by com.cloudera.impala.analysis.Path.createRelPath().

com.cloudera.impala.analysis.Path.Path	(	Table	rootTable,
		List< String >	rawPath
	)

inline

Constructs a Path rooted at the given rootTable.

Definition at line 134 of file Path.java.

References com.cloudera.impala.analysis.Path.rawPath_, com.cloudera.impala.analysis.Path.rootDesc_, com.cloudera.impala.analysis.Path.rootPath_, and com.cloudera.impala.analysis.Path.rootTable_.

com.cloudera.impala.analysis.Path.Path	(	Path	rootPath,
		List< String >	relRawPath
	)

inline

Constructs a new unresolved path relative to an existing resolved path.

Definition at line 146 of file Path.java.

References com.cloudera.impala.analysis.Path.firstCollectionPathIdx_, com.cloudera.impala.analysis.Path.firstCollectionTypeIdx_, com.cloudera.impala.analysis.Path.rawPath_, com.cloudera.impala.analysis.Path.rootDesc_, com.cloudera.impala.analysis.Path.rootPath_, and com.cloudera.impala.analysis.Path.rootTable_.

Member Function Documentation

static ArrayList<String> com.cloudera.impala.analysis.Path.createRawPath	(	String	rootAlias,
		String	fieldName
	)

inlinestatic

Returns a raw path from a known root alias and field name.

Definition at line 350 of file Path.java.

Referenced by com.cloudera.impala.analysis.TableRef.analyzeJoin().

static Path com.cloudera.impala.analysis.Path.createRelPath	(	Path	rootPath,
		String...	fieldNames
	)

inlinestatic

Definition at line 356 of file Path.java.

References com.cloudera.impala.analysis.Path.Path().

Column com.cloudera.impala.analysis.Path.destColumn ( )

inline

Returns the destination Column of this path, or null if the destination of this path is not a Column. This path must be rooted at a table or a tuple descriptor corresponding to a table for the destination to be a Column.

Definition at line 292 of file Path.java.

References com.cloudera.impala.analysis.Path.isResolved_, com.cloudera.impala.analysis.Path.rawPath_, and com.cloudera.impala.analysis.Path.rootTable_.

Table com.cloudera.impala.analysis.Path.destTable ( )

inline

Definition at line 279 of file Path.java.

References com.cloudera.impala.analysis.Path.isResolved_, com.cloudera.impala.analysis.Path.matchedTypes_, com.cloudera.impala.analysis.Path.rootDesc_, and com.cloudera.impala.analysis.Path.rootTable_.

Referenced by com.cloudera.impala.analysis.TupleDescriptor.setPath().

TupleDescriptor com.cloudera.impala.analysis.Path.destTupleDesc ( )

inline

Returns the destination tuple descriptor of this path, or null if the destination of this path is not a registered alias.

Definition at line 302 of file Path.java.

References com.cloudera.impala.analysis.Path.isResolved_, com.cloudera.impala.analysis.Path.matchedTypes_, and com.cloudera.impala.analysis.Path.rootDesc_.

Type com.cloudera.impala.analysis.Path.destType ( )

inline

Definition at line 271 of file Path.java.

References com.cloudera.impala.analysis.Path.isResolved_, com.cloudera.impala.analysis.Path.matchedTypes_, com.cloudera.impala.analysis.Path.rootDesc_, and com.cloudera.impala.analysis.Path.rootTable_.

List<Integer> com.cloudera.impala.analysis.Path.getAbsolutePath ( )

inline

Returns the absolute physical path in positions starting from the schema root to the destination of this path.

Definition at line 325 of file Path.java.

References com.cloudera.impala.analysis.Path.absolutePath_, com.cloudera.impala.analysis.Path.isResolved_, com.cloudera.impala.analysis.Path.matchedPositions_, and com.cloudera.impala.analysis.Path.rootDesc_.

String com.cloudera.impala.analysis.Path.getFirstCollectionName ( )

inline

Definition at line 259 of file Path.java.

References com.cloudera.impala.analysis.Path.firstCollectionPathIdx_, and com.cloudera.impala.analysis.Path.isResolved_.

Type com.cloudera.impala.analysis.Path.getFirstCollectionType ( )

inline

Definition at line 265 of file Path.java.

References com.cloudera.impala.analysis.Path.firstCollectionTypeIdx_, and com.cloudera.impala.analysis.Path.isResolved_.

List<String> com.cloudera.impala.analysis.Path.getFullyQualifiedRawPath ( )

inline

Definition at line 308 of file Path.java.

References com.cloudera.impala.analysis.Path.rawPath_, com.cloudera.impala.analysis.Path.rootDesc_, and com.cloudera.impala.analysis.Path.rootTable_.

List<Integer> com.cloudera.impala.analysis.Path.getMatchedPositions ( )

inline

Definition at line 248 of file Path.java.

References com.cloudera.impala.analysis.Path.isResolved_, and com.cloudera.impala.analysis.Path.matchedPositions_.

List<Type> com.cloudera.impala.analysis.Path.getMatchedTypes ( )

inline

Definition at line 243 of file Path.java.

References com.cloudera.impala.analysis.Path.isResolved_, and com.cloudera.impala.analysis.Path.matchedTypes_.

List<String> com.cloudera.impala.analysis.Path.getRawPath ( )

inline

Definition at line 240 of file Path.java.

References com.cloudera.impala.analysis.Path.rawPath_.

Referenced by com.cloudera.impala.analysis.SlotDescriptor.setPath().

TupleDescriptor com.cloudera.impala.analysis.Path.getRootDesc ( )

inline

Definition at line 239 of file Path.java.

References com.cloudera.impala.analysis.Path.rootDesc_.

Referenced by com.cloudera.impala.analysis.CollectionTableRef.analyze().

Table com.cloudera.impala.analysis.Path.getRootTable ( )

inline

Definition at line 238 of file Path.java.

References com.cloudera.impala.analysis.Path.rootTable_.

Referenced by com.cloudera.impala.analysis.TableRef.analyze().

static StructType com.cloudera.impala.analysis.Path.getTypeAsStruct ( Type t )

inlinestatic

If the given type is a collection, returns a collection struct type representing named fields of its explicit path. Returns the given type itself if it is already a struct. Requires that the given type is a complex type.

Definition at line 227 of file Path.java.

References com.cloudera.impala.catalog.Type.isArrayType(), and com.cloudera.impala.catalog.Type.isStructType().

Referenced by com.cloudera.impala.analysis.Path.resolve().

boolean com.cloudera.impala.analysis.Path.hasNonDestCollection ( )

inline

Definition at line 253 of file Path.java.

References com.cloudera.impala.analysis.Path.firstCollectionPathIdx_, and com.cloudera.impala.analysis.Path.isResolved_.

boolean com.cloudera.impala.analysis.Path.isResolved ( )

inline

Definition at line 241 of file Path.java.

References com.cloudera.impala.analysis.Path.isResolved_.

boolean com.cloudera.impala.analysis.Path.resolve ( )

inline

Resolves this path in the context of the root tuple descriptor / root table or continues resolving this relative path from an existing root path. Returns true if the path could be fully resolved, false otherwise. A failed resolution leaves this Path in a partially resolved state.

Definition at line 169 of file Path.java.