Package com.apple.foundationdb.record.query.plan.temp.matchers

Class PlannerBindings

java.lang.Object

com.apple.foundationdb.record.query.plan.temp.matchers.PlannerBindings

@API(EXPERIMENTAL)
public class PlannerBindings
extends Object

A map-like structure that supports a map from a binding to a collection of Bindables, such as RelationalExpressions and ExpressionRefs. A binding's key is a pointer to the ExpressionMatcher that created the binding, eliminating the need for a unique string or symbol identifier. A PlannerBindings is immutable but has a PlannerBindings.Builder that can be used to build up a set of bindings incrementally. Additionally, bindings can be combined using mergedWith(PlannerBindings).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	PlannerBindings.Builder	A mutable builder for a set of PlannerBindings which can be used to incrementally build up a set of bindings without repeatedly calling mergedWith(PlannerBindings), which is less efficient.

Method Summary

Modifier and Type	Method	Description
com.google.common.collect.ImmutableListMultimap<ExpressionMatcher<? extends Bindable>,Bindable>	asMultiMap()	Return the bindings as multimap for callers that need reason about all bindings in a generic manner, e.g.
boolean	containsKey(ExpressionMatcher<? extends Bindable> key)	Checks whether there is a bindable bound to key.
static PlannerBindings	empty()	Return an empty set of bindings.
static PlannerBindings	from(ExpressionMatcher<? extends Bindable> key, Bindable bindable)	Build a new set of bindings containing a single binding from the given key to the given bindable.
<T extends Bindable> T	get(ExpressionMatcher<T> key)	Retrieve the single bindable bound to key.
<T extends Bindable> List<T>	getAll(ExpressionMatcher<T> key)	Retrieve all Bindables bound to key if there is at least one such bindable.
PlannerBindings	mergedWith(PlannerBindings other)	Combine this set of bindings with the given set of bindings.
static PlannerBindings.Builder	newBuilder()	Return a new builder.

Methods inherited from class java.lang.Object

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

Method Detail

containsKey

public boolean containsKey(@Nonnull
                           ExpressionMatcher<? extends Bindable> key)

Checks whether there is a bindable bound to key.

Parameters:

key - a matcher

Returns:

whether there is an object bound to key

get

@Nonnull
public <T extends Bindable> T get(@Nonnull
                                  ExpressionMatcher<T> key)

Retrieve the single bindable bound to key. This method is meant to be a convenient shortcut for the case where the developer is certain that precisely one bindable could be bound to this key. If no bindable is bound to this key, or if there are multiple Bindables bound to this key, this throws a NoSuchElementException.

Type Parameters:

T - the type of Bindable that was bound to key

Parameters:

key - a matcher

Returns:

the bindable object bound to key

Throws:

NoSuchElementException - if the number of bindables bound to this key is not exactly one

getAll

@Nonnull
public <T extends Bindable> List<T> getAll(@Nonnull
                                           ExpressionMatcher<T> key)

Retrieve all Bindables bound to key if there is at least one such bindable. The bindables in the returned list appear in same order as they appear in the list of children of the RelationalExpression that produced this set of bindings. If no bindable is bound to this key, throw a NoSuchElementException.

Type Parameters:

T - the type of Bindable that was bound to key

Parameters:

key - a matcher

Returns:

a list of bindable objects bound to the key

mergedWith

@Nonnull
public PlannerBindings mergedWith(@Nonnull
                                  PlannerBindings other)

Combine this set of bindings with the given set of bindings. If both sets of bindings contain a binding with the same key, the resulting set of bindings will contain the concatenation of the bindables from this set of bindings and the bindables from the given set of bindings, in that order, providing a predictable ordering of bindings for planner rules that might need it.

Parameters:

other - a set of bindings, which may share keys with this set of bindings

Returns:

a new set of bindings that contains the bindings from both both sets of bindings

asMultiMap

@Nonnull
public com.google.common.collect.ImmutableListMultimap<ExpressionMatcher<? extends Bindable>,Bindable> asMultiMap()

Return the bindings as multimap for callers that need reason about all bindings in a generic manner, e.g. this can be used by implementations of Debugger to show the contents of all bindings without the knowledge of the existence of particular matchers.

Returns:

the backing immutable multi map

from

@Nonnull
public static PlannerBindings from(@Nonnull
                                   ExpressionMatcher<? extends Bindable> key,
                                   @Nonnull
                                   Bindable bindable)

Build a new set of bindings containing a single binding from the given key to the given bindable.

Parameters:

key - an expression matcher

bindable - a bindable object

Returns:

a new set of bindings containing a single binding from key to bindable

empty

@Nonnull
public static PlannerBindings empty()

Return an empty set of bindings.

Returns:

an empty set of bindings

newBuilder

public static PlannerBindings.Builder newBuilder()

Return a new builder.

Returns:

a new builder