java.lang.Object
- org.apache.calcite.rel.AbstractRelNode

All Implemented Interfaces:

java.lang.Cloneable, RelOptNode, RelNode

Direct Known Subclasses:

BiRel, DruidQuery, HepRelVertex, MultiJoin, RelSubset, SetOp, SingleRel, TableFunctionScan, TableScan, Values
```
public abstract class AbstractRelNode
extends java.lang.Object
implements RelNode
```
Base class for every relational expression (RelNode).

Nested Class Summary
- Nested classes/interfaces inherited from interface org.apache.calcite.rel.RelNode
  RelNode.Context

Field Summary

Fields
Modifier and Type	Field	Description
`private RelOptCluster`	`cluster`
`private java.lang.String`	`desc`	Description, consists of id plus digest.
`protected java.lang.String`	`digest`	A short description of this relational expression's type, inputs, and other properties.
`protected int`	`id`	unique id of this object -- for debugging
`private static org.slf4j.Logger`	`LOGGER`
`private static java.util.concurrent.atomic.AtomicInteger`	`NEXT_ID`	Generator for `id` values.
`protected RelDataType`	`rowType`	Cached type of this relational expression.
`protected RelTraitSet`	`traitSet`	The RelTraitSet that describes the traits of this RelNode.

Constructor Summary

Constructors
Constructor Description

AbstractRelNode(RelOptCluster cluster, RelTraitSet traitSet)
Creates an AbstractRelNode.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`RelNode`	`accept(RelShuttle shuttle)`	Accepts a visit from a shuttle.
`RelNode`	`accept(RexShuttle shuttle)`	Accepts a visit from a shuttle.
`void`	`childrenAccept(RelVisitor visitor)`	Interacts with the `RelVisitor` in a `visitor pattern` to traverse the tree of relational expressions.
`void`	`collectVariablesSet(java.util.Set<CorrelationId> variableSet)`	Collects variables set by this expression.
`void`	`collectVariablesUsed(java.util.Set<CorrelationId> variableSet)`	Collects variables known to be used by this expression or its descendants.
`protected java.lang.String`	`computeDigest()`	Computes the digest.
`RelOptCost`	`computeSelfCost(RelOptPlanner planner)`
`RelOptCost`	`computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq)`	Returns the cost of this plan (not including children).
`RelNode`	`copy(RelTraitSet traitSet, java.util.List<RelNode> inputs)`	Creates a copy of this relational expression, perhaps changing traits and inputs.
`protected RelDataType`	`deriveRowType()`
`double`	`estimateRowCount(RelMetadataQuery mq)`	Returns an estimate of the number of rows this relational expression will return.
`void`	`explain(RelWriter pw)`	Describes the inputs and attributes of this relational expression.
`RelWriter`	`explainTerms(RelWriter pw)`	Describes the inputs and attributes of this relational expression.
`java.util.List<RexNode>`	`getChildExps()`	Returns a list of this relational expression's child expressions.
`RelOptCluster`	`getCluster()`	Returns the cluster this relational expression belongs to.
`java.util.List<RelCollation>`	`getCollationList()`	Deprecated. Use `RelMetadataQuery.collations(RelNode)`
`Convention`	`getConvention()`	Return the CallingConvention trait from this RelNode's `trait set`.
`java.lang.String`	`getCorrelVariable()`	Returns the name of the variable which is to be implicitly set at runtime each time a row is returned from the first input of this relational expression; or null if there is no variable.
`java.lang.String`	`getDescription()`	Returns a string which describes the relational expression and, unlike `RelOptNode.getDigest()`, also includes the identity.
`java.lang.String`	`getDigest()`	Returns a string which concisely describes the definition of this relational expression.
`RelDataType`	`getExpectedInputRowType(int ordinalInParent)`	Returns the type of the rows expected for an input.
`int`	`getId()`	Returns the ID of this relational expression, unique among all relational expressions created since the server was started.
`RelNode`	`getInput(int i)`	Returns the `i`^th input relational expression.
`java.util.List<RelNode>`	`getInputs()`	Returns an array of this relational expression's inputs.
`RelOptQuery`	`getQuery()`	Returns the sub-query this relational expression belongs to.
`java.lang.String`	`getRelTypeName()`	Returns the name of this relational expression's class, sans package name, for use in explain.
`double`	`getRows()`
`RelDataType`	`getRowType()`	Returns the type of the rows returned by this relational expression.
`RelOptTable`	`getTable()`	If this relational expression represents an access to a table, returns that table, otherwise returns null.
`RelTraitSet`	`getTraitSet()`	Retrieves this RelNode's traits.
`java.util.Set<CorrelationId>`	`getVariablesSet()`	Returns the variables that are set in this relational expression but also used and therefore not available to parents of this relational expression.
`java.util.Set<java.lang.String>`	`getVariablesStopped()`	Returns the names of variables that are set in this relational expression but also used and therefore not available to parents of this relational expression.
`boolean`	`isDistinct()`	Returns whether the same value will not come out twice.
`boolean`	`isKey(ImmutableBitSet columns)`	Returns whether the result of this relational expression is uniquely identified by this columns with the given ordinals.
`boolean`	`isValid(boolean fail)`
`boolean`	`isValid(Litmus litmus, RelNode.Context context)`	Returns whether this relational expression is valid.
`<M extends Metadata> M`	`metadata(java.lang.Class<M> metadataClass, RelMetadataQuery mq)`	Returns a metadata interface.
`RelNode`	`onRegister(RelOptPlanner planner)`	Receives notification that this expression is about to be registered.
`java.lang.String`	`recomputeDigest()`	Computes the digest, assigns it, and returns it.
`void`	`register(RelOptPlanner planner)`	Registers any special rules specific to this kind of relational expression.
`void`	`replaceInput(int ordinalInParent, RelNode p)`	Replaces the `ordinalInParent`^th input.
`protected static <T> T`	`sole(java.util.List<T> collection)`
`java.lang.String`	`toString()`

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

- Field Detail
  - NEXT_ID
```
private static final java.util.concurrent.atomic.AtomicInteger NEXT_ID
```
    Generator for id values.
  - LOGGER
```
private static final org.slf4j.Logger LOGGER
```
  - desc
```
private java.lang.String desc
```
    Description, consists of id plus digest.
  - rowType
```
protected RelDataType rowType
```
    Cached type of this relational expression.
  - digest
```
protected java.lang.String digest
```
    A short description of this relational expression's type, inputs, and other properties. The string uniquely identifies the node; another node is equivalent if and only if it has the same value. Computed by computeDigest(), assigned by onRegister(org.apache.calcite.plan.RelOptPlanner), returned by getDigest().
    
    See Also:
    
    desc
  - cluster
```
private final RelOptCluster cluster
```
  - id
```
protected final int id
```
    unique id of this object -- for debugging
  - traitSet
```
protected RelTraitSet traitSet
```
    The RelTraitSet that describes the traits of this RelNode.
- Constructor Detail
  - AbstractRelNode
```
public AbstractRelNode(RelOptCluster cluster,
                       RelTraitSet traitSet)
```
    Creates an AbstractRelNode.
- Method Detail
  - copy
```
public RelNode copy(RelTraitSet traitSet,
                    java.util.List<RelNode> inputs)
```
    Description copied from interface: RelNode
    
    Creates a copy of this relational expression, perhaps changing traits and inputs.
    Sub-classes with other important attributes are encouraged to create variants of this method with more parameters.
    
    Specified by:
    
    copy in interface RelNode
    
    Parameters:
    
    traitSet - Trait set
    
    inputs - Inputs
    
    Returns:
    
    Copy of this relational expression, substituting traits and inputs
  - sole
```
protected static <T> T sole(java.util.List<T> collection)
```
  - getChildExps
```
public java.util.List<RexNode> getChildExps()
```
    Description copied from interface: RelNode
    
    Returns a list of this relational expression's child expressions. (These are scalar expressions, and so do not include the relational inputs that are returned by RelNode.getInputs().
    The caller should treat the list as unmodifiable; typical implementations will return an immutable list. If there are no child expressions, returns an empty list, not null.
    
    Specified by:
    
    getChildExps in interface RelNode
    
    Returns:
    
    List of this relational expression's child expressions
    
    See Also:
    
    RelNode.accept(org.apache.calcite.rex.RexShuttle)
  - getCluster
```
public final RelOptCluster getCluster()
```
    Description copied from interface: RelOptNode
    
    Returns the cluster this relational expression belongs to.
    
    Specified by:
    
    getCluster in interface RelOptNode
    
    Returns:
    
    cluster
  - getConvention
```
public final Convention getConvention()
```
    Description copied from interface: RelNode
    
    Return the CallingConvention trait from this RelNode's trait set.
    
    Specified by:
    
    getConvention in interface RelNode
    
    Returns:
    
    this RelNode's CallingConvention
  - getTraitSet
```
public RelTraitSet getTraitSet()
```
    Description copied from interface: RelOptNode
    
    Retrieves this RelNode's traits. Note that although the RelTraitSet returned is modifiable, it must not be modified during optimization. It is legal to modify the traits of a RelNode before or after optimization, although doing so could render a tree of RelNodes unimplementable. If a RelNode's traits need to be modified during optimization, clone the RelNode and change the clone's traits.
    
    Specified by:
    
    getTraitSet in interface RelOptNode
    
    Returns:
    
    this RelNode's trait set
  - getCorrelVariable
```
public java.lang.String getCorrelVariable()
```
    Description copied from interface: RelNode
    
    Returns the name of the variable which is to be implicitly set at runtime each time a row is returned from the first input of this relational expression; or null if there is no variable.
    
    Specified by:
    
    getCorrelVariable in interface RelNode
    
    Returns:
    
    Name of correlating variable, or null
  - isDistinct
```
public boolean isDistinct()
```
    Description copied from interface: RelNode
    
    Returns whether the same value will not come out twice. Default value is false, derived classes should override.
    
    Specified by:
    
    isDistinct in interface RelNode
    
    Returns:
    
    Whether the same value will not come out twice
  - isKey
```
public boolean isKey(ImmutableBitSet columns)
```
    Description copied from interface: RelNode
    
    Returns whether the result of this relational expression is uniquely identified by this columns with the given ordinals.
    For example, if this relational expression is a LogicalTableScan to T(A, B, C, D) whose key is (A, B), then isKey([0, 1]) yields true, and isKey([0]) and isKey([0, 2]) yields false.
    
    Specified by:
    
    isKey in interface RelNode
    
    Parameters:
    
    columns - Ordinals of key columns
    
    Returns:
    
    Whether the given columns are a key or a superset of a key
  - getId
```
public int getId()
```
    Description copied from interface: RelOptNode
    
    Returns the ID of this relational expression, unique among all relational expressions created since the server was started.
    
    Specified by:
    
    getId in interface RelOptNode
    
    Returns:
    
    Unique ID
  - getInput
```
public RelNode getInput(int i)
```
    Description copied from interface: RelNode
    
    Returns the i^th input relational expression.
    
    Specified by:
    
    getInput in interface RelNode
    
    Parameters:
    
    i - Ordinal of input
    
    Returns:
    
    i^th input
  - getQuery
```
public final RelOptQuery getQuery()
```
    Description copied from interface: RelNode
    
    Returns the sub-query this relational expression belongs to.
    
    Specified by:
    
    getQuery in interface RelNode
    
    Returns:
    
    Sub-query
  - register
```
public void register(RelOptPlanner planner)
```
    Description copied from interface: RelNode
    
    Registers any special rules specific to this kind of relational expression.
    The planner calls this method this first time that it sees a relational expression of this class. The derived class should call RelOptPlanner.addRule(org.apache.calcite.plan.RelOptRule) for each rule, and then call super.register.
    
    Specified by:
    
    register in interface RelNode
    
    Parameters:
    
    planner - Planner to be used to register additional relational expressions
  - getRelTypeName
```
public final java.lang.String getRelTypeName()
```
    Description copied from interface: RelNode
    
    Returns the name of this relational expression's class, sans package name, for use in explain. For example, for a org.apache.calcite.rel.ArrayRel.ArrayReader, this method returns "ArrayReader".
    
    Specified by:
    
    getRelTypeName in interface RelNode
    
    Returns:
    
    Name of this relational expression's class, sans package name, for use in explain
  - isValid
```
public boolean isValid(Litmus litmus,
                       RelNode.Context context)
```
    Description copied from interface: RelNode
    Returns whether this relational expression is valid.
    If assertions are enabled, this method is typically called with litmus = THROW, as follows:
    
    assert rel.isValid(Litmus.THROW)
    
    This signals that the method can throw an AssertionError if it is not valid.
    Specified by:
    
    isValid in interface RelNode
    
    Parameters:
    
    litmus - What to do if invalid
    
    context - Context for validity checking
    
    Returns:
    
    Whether relational expression is valid
  - isValid
```
public boolean isValid(boolean fail)
```
    Specified by:
    
    isValid in interface RelNode
  - getCollationList
```
@Deprecated
public java.util.List<RelCollation> getCollationList()
```
    Deprecated.
    Use RelMetadataQuery.collations(RelNode)
    
    Description copied from interface: RelNode
    
    Returns a description of the physical ordering (or orderings) of this relational expression. Never null.
    
    Specified by:
    
    getCollationList in interface RelNode
    
    Returns:
    
    Description of the physical ordering (or orderings) of this relational expression. Never null
  - getRowType
```
public final RelDataType getRowType()
```
    Description copied from interface: RelNode
    
    Returns the type of the rows returned by this relational expression.
    
    Specified by:
    
    getRowType in interface RelNode
    
    Specified by:
    
    getRowType in interface RelOptNode
  - deriveRowType
```
protected RelDataType deriveRowType()
```
  - getExpectedInputRowType
```
public RelDataType getExpectedInputRowType(int ordinalInParent)
```
    Description copied from interface: RelNode
    
    Returns the type of the rows expected for an input. Defaults to RelNode.getRowType().
    
    Specified by:
    
    getExpectedInputRowType in interface RelNode
    
    Parameters:
    
    ordinalInParent - input's 0-based ordinal with respect to this parent rel
    
    Returns:
    
    expected row type
  - getInputs
```
public java.util.List<RelNode> getInputs()
```
    Description copied from interface: RelNode
    
    Returns an array of this relational expression's inputs. If there are no inputs, returns an empty list, not null.
    
    Specified by:
    
    getInputs in interface RelNode
    
    Specified by:
    
    getInputs in interface RelOptNode
    
    Returns:
    
    Array of this relational expression's inputs
  - getRows
```
public final double getRows()
```
    Specified by:
    
    getRows in interface RelNode
  - estimateRowCount
```
public double estimateRowCount(RelMetadataQuery mq)
```
    Description copied from interface: RelNode
    
    Returns an estimate of the number of rows this relational expression will return.
    NOTE jvs 29-Mar-2006: Don't call this method directly. Instead, use RelMetadataQuery.getRowCount(org.apache.calcite.rel.RelNode), which gives plugins a chance to override the rel's default ideas about row count.
    
    Specified by:
    
    estimateRowCount in interface RelNode
    
    Parameters:
    
    mq - Metadata query
    
    Returns:
    
    Estimate of the number of rows this relational expression will return
  - getVariablesStopped
```
public final java.util.Set<java.lang.String> getVariablesStopped()
```
    Description copied from interface: RelNode
    
    Returns the names of variables that are set in this relational expression but also used and therefore not available to parents of this relational expression.
    Note: only Correlate should set variables.
    Note: RelNode.getVariablesSet() is equivalent but returns CorrelationId rather than their names. It is preferable except for calling old methods that require a set of strings.
    
    Specified by:
    
    getVariablesStopped in interface RelNode
    
    Returns:
    
    Names of variables which are set in this relational expression
  - getVariablesSet
```
public java.util.Set<CorrelationId> getVariablesSet()
```
    Description copied from interface: RelNode
    
    Returns the variables that are set in this relational expression but also used and therefore not available to parents of this relational expression.
    Note: only Correlate should set variables.
    
    Specified by:
    
    getVariablesSet in interface RelNode
    
    Returns:
    
    Names of variables which are set in this relational expression
  - collectVariablesUsed
```
public void collectVariablesUsed(java.util.Set<CorrelationId> variableSet)
```
    Description copied from interface: RelNode
    
    Collects variables known to be used by this expression or its descendants. By default, no such information is available and must be derived by analyzing sub-expressions, but some optimizer implementations may insert special expressions which remember such information.
    
    Specified by:
    
    collectVariablesUsed in interface RelNode
    
    Parameters:
    
    variableSet - receives variables used
  - collectVariablesSet
```
public void collectVariablesSet(java.util.Set<CorrelationId> variableSet)
```
    Description copied from interface: RelNode
    
    Collects variables set by this expression. TODO: is this required?
    
    Specified by:
    
    collectVariablesSet in interface RelNode
    
    Parameters:
    
    variableSet - receives variables known to be set by
  - childrenAccept
```
public void childrenAccept(RelVisitor visitor)
```
    Description copied from interface: RelNode
    
    Interacts with the RelVisitor in a visitor pattern to traverse the tree of relational expressions.
    
    Specified by:
    
    childrenAccept in interface RelNode
    
    Parameters:
    
    visitor - Visitor that will traverse the tree of relational expressions
  - accept
```
public RelNode accept(RelShuttle shuttle)
```
    Description copied from interface: RelNode
    
    Accepts a visit from a shuttle.
    
    Specified by:
    
    accept in interface RelNode
    
    Parameters:
    
    shuttle - Shuttle
    
    Returns:
    
    A copy of this node incorporating changes made by the shuttle to this node's children
  - accept
```
public RelNode accept(RexShuttle shuttle)
```
    Description copied from interface: RelNode
    
    Accepts a visit from a shuttle. If the shuttle updates expression, then a copy of the relation should be created.
    
    Specified by:
    
    accept in interface RelNode
    
    Parameters:
    
    shuttle - Shuttle
    
    Returns:
    
    A copy of this node incorporating changes made by the shuttle to this node's children
  - computeSelfCost
```
public final RelOptCost computeSelfCost(RelOptPlanner planner)
```
    Specified by:
    
    computeSelfCost in interface RelNode
  - computeSelfCost
```
public RelOptCost computeSelfCost(RelOptPlanner planner,
                                  RelMetadataQuery mq)
```
    Description copied from interface: RelNode
    
    Returns the cost of this plan (not including children). The base implementation throws an error; derived classes should override.
    NOTE jvs 29-Mar-2006: Don't call this method directly. Instead, use RelMetadataQuery.getNonCumulativeCost(org.apache.calcite.rel.RelNode), which gives plugins a chance to override the rel's default ideas about cost.
    
    Specified by:
    
    computeSelfCost in interface RelNode
    
    Parameters:
    
    planner - Planner for cost calculation
    
    mq - Metadata query
    
    Returns:
    
    Cost of this plan (not including children)
  - metadata
```
public final <M extends Metadata> M metadata(java.lang.Class<M> metadataClass,
                                             RelMetadataQuery mq)
```
    Description copied from interface: RelNode
    
    Returns a metadata interface.
    
    Specified by:
    
    metadata in interface RelNode
    
    Type Parameters:
    
    M - Type of metadata being requested
    
    Parameters:
    
    metadataClass - Metadata interface
    
    mq - Metadata query
    
    Returns:
    
    Metadata object that supplies the desired metadata (never null, although if the information is not present the metadata object may return null from all methods)
  - explain
```
public void explain(RelWriter pw)
```
    Description copied from interface: RelNode
    
    Describes the inputs and attributes of this relational expression. Each node should call super.explain, then call the RelWriterImpl.input(String, RelNode) and RelWriterImpl.item(String, Object) methods for each input and attribute.
    
    Specified by:
    
    explain in interface RelNode
    
    Parameters:
    
    pw - Plan writer
  - explainTerms
```
public RelWriter explainTerms(RelWriter pw)
```
    Describes the inputs and attributes of this relational expression. Each node should call super.explainTerms, then call the RelWriterImpl.input(String, RelNode) and RelWriterImpl.item(String, Object) methods for each input and attribute.
    
    Parameters:
    
    pw - Plan writer
    
    Returns:
    
    Plan writer for fluent-explain pattern
  - onRegister
```
public RelNode onRegister(RelOptPlanner planner)
```
    Description copied from interface: RelNode
    
    Receives notification that this expression is about to be registered. The implementation of this method must at least register all child expressions.
    
    Specified by:
    
    onRegister in interface RelNode
    
    Parameters:
    
    planner - Planner that plans this relational node
    
    Returns:
    
    Relational expression that should be used by the planner
  - recomputeDigest
```
public java.lang.String recomputeDigest()
```
    Description copied from interface: RelNode
    
    Computes the digest, assigns it, and returns it. For planner use only.
    
    Specified by:
    
    recomputeDigest in interface RelNode
    
    Returns:
    
    Digest of this relational expression
  - replaceInput
```
public void replaceInput(int ordinalInParent,
                         RelNode p)
```
    Description copied from interface: RelNode
    
    Replaces the ordinalInParent^th input. You must override this method if you override RelNode.getInputs().
    
    Specified by:
    
    replaceInput in interface RelNode
    
    Parameters:
    
    ordinalInParent - Position of the child input, 0 is the first
    
    p - New node that should be put at position ordinalInParent
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - getDescription
```
public final java.lang.String getDescription()
```
    Description copied from interface: RelOptNode
    
    Returns a string which describes the relational expression and, unlike RelOptNode.getDigest(), also includes the identity. Typically returns "rel#{id}:{digest}".
    
    Specified by:
    
    getDescription in interface RelOptNode
    
    Returns:
    
    String which describes the relational expression and, unlike RelOptNode.getDigest(), also includes the identity
  - getDigest
```
public final java.lang.String getDigest()
```
    Description copied from interface: RelOptNode
    
    Returns a string which concisely describes the definition of this relational expression. Two relational expressions are equivalent if and only if their digests are the same.
    The digest does not contain the relational expression's identity -- that would prevent similar relational expressions from ever comparing equal -- but does include the identity of children (on the assumption that children have already been normalized).
    If you want a descriptive string which contains the identity, call Object.toString(), which always returns "rel#{id}:{digest}".
    
    Specified by:
    
    getDigest in interface RelOptNode
    
    Returns:
    
    Digest of this RelNode
  - getTable
```
public RelOptTable getTable()
```
    Description copied from interface: RelNode
    
    If this relational expression represents an access to a table, returns that table, otherwise returns null.
    
    Specified by:
    
    getTable in interface RelNode
    
    Returns:
    
    If this relational expression represents an access to a table, returns that table, otherwise returns null
  - computeDigest
```
protected java.lang.String computeDigest()
```
    Computes the digest. Does not modify this object.
    
    Returns:
    
    Digest

Class AbstractRelNode

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.calcite.rel.RelNode

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

NEXT_ID

LOGGER

desc

rowType

digest

cluster

id

traitSet

Constructor Detail

AbstractRelNode

Method Detail

copy

sole

getChildExps

getCluster

getConvention

getTraitSet

getCorrelVariable

isDistinct

isKey

getId

getInput

getQuery

register

getRelTypeName

isValid

isValid

getCollationList

getRowType

deriveRowType

getExpectedInputRowType

getInputs

getRows

estimateRowCount

getVariablesStopped

getVariablesSet

collectVariablesUsed

collectVariablesSet

childrenAccept

accept

accept

computeSelfCost

computeSelfCost

metadata

explain

explainTerms

onRegister

recomputeDigest

replaceInput

toString

getDescription

getDigest

getTable

computeDigest