org.apache.jackrabbit.oak.query.ast

Class ConstraintImpl

java.lang.Object

org.apache.jackrabbit.oak.query.ast.ConstraintImpl

Direct Known Subclasses:

AndImpl, ChildNodeImpl, ComparisonImpl, DescendantNodeImpl, FullTextSearchImpl, InImpl, NativeFunctionImpl, NotImpl, OrImpl, PropertyExistenceImpl, PropertyInexistenceImpl, SameNodeImpl, SimilarImpl, SpellcheckImpl, SuggestImpl

public abstract class ConstraintImpl
extends Object

The base class for constraints.

Field Summary

Fields

Modifier and Type	Field and Description
protected QueryImpl	query

Constructor Summary

Constructors

Constructor and Description
ConstraintImpl()

Method Summary

Modifier and Type	Method and Description
boolean	containsUnfilteredFullTextCondition() Whether the condition contains a fulltext condition that can not be applied to the filter, for example because it is part of an "or" condition of the form "where a=1 or contains(., 'x')".
@NotNull Set<ConstraintImpl>	convertToUnion() Compute a set of sub-constraints that could be used for composing UNION statements.
protected PropertyValue	convertValueToType(PropertyValue v, PropertyValue targetType)
@NotNull org.apache.jackrabbit.oak.query.ast.AstElement	copyOf()
boolean	equals(Object other)
abstract boolean	evaluate() Evaluate the result using the currently set values.
boolean	evaluateStop() Whether this condition will, from now on, always evaluate to false.
FullTextExpression	getFullTextConstraint(SelectorImpl s) Get the (combined) full-text constraint.
protected String	getLocalPath(String path) Calculate the session local path (the path excluding the workspace name) if possible.
abstract Set<PropertyExistenceImpl>	getPropertyExistenceConditions() Get the set of property existence conditions that can be derived for this condition.
abstract Set<SelectorImpl>	getSelectors() Get the set of selectors for the given condition.
int	hashCode()
protected String	normalizePath(String path) Validate and normalize the path.
protected String	normalizePropertyName(String propertyName) Normalize the property name (including namespace remapping).
protected String	protect(Object expression)
protected String	quote(String pathOrName)
protected String	quoteJson(String string)
boolean	requiresFullTextIndex() Whether the constraint contains a fulltext condition that requires using a fulltext index, because the condition can only be evaluated there.
abstract void	restrict(FilterImpl f) Apply the condition to the filter, further restricting the filter if possible.
abstract void	restrictPushDown(SelectorImpl s) Push as much of the condition down to this selector, further restricting the selector condition if possible.
void	setQuery(QueryImpl query)
ConstraintImpl	simplify() Simplify the expression if possible, for example by removing duplicate expressions.

Methods inherited from class java.lang.Object

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

Field Detail

query

protected QueryImpl query

Constructor Detail

ConstraintImpl

public ConstraintImpl()

Method Detail

simplify

public ConstraintImpl simplify()

Simplify the expression if possible, for example by removing duplicate expressions. For example, "x=1 or x=1" should be simplified to "x=1".

Returns:

the simplified constraint, or "this" if it is not possible to simplify

evaluate

public abstract boolean evaluate()

Evaluate the result using the currently set values.

Returns:

true if the constraint matches

evaluateStop

public boolean evaluateStop()

Whether this condition will, from now on, always evaluate to false. This is the case for example for full-text constraints if there is no full-text index (unless FullTextComparisonWithoutIndex is enabled). This will also allow is to add conditions that stop further processing for other reasons, similar to "WHERE ROWNUM < 10" in Oracle.

Returns:

true if further processing should be stopped

getPropertyExistenceConditions

public abstract Set<PropertyExistenceImpl> getPropertyExistenceConditions()

Get the set of property existence conditions that can be derived for this condition. For example, for the condition "x=1 or x=2", the property existence condition is "x is not null". For the condition "x=1 or y=2", there is no such condition. For the condition "x=1 and y=1", there are two (x is not null, and y is not null).

Returns:

the common property existence condition (possibly empty)

getFullTextConstraint

public FullTextExpression getFullTextConstraint(SelectorImpl s)

Get the (combined) full-text constraint. For constraints of the form "contains(*, 'x') or contains(*, 'y')", the combined expression is returned. If there is none, null is returned. For constraints of the form "contains(*, 'x') or z=1", null is returned as the full-text index cannot be used in this case for filtering (as it might filter out the z=1 nodes).

Parameters:

s - the selector

Returns:

the full-text constraint, if there is any, or null if not

getSelectors

public abstract Set<SelectorImpl> getSelectors()

Get the set of selectors for the given condition.

Returns:

the set of selectors (possibly empty)

restrict

public abstract void restrict(FilterImpl f)

Apply the condition to the filter, further restricting the filter if possible. This may also verify the data types are compatible, and that paths are valid.

Parameters:

f - the filter

restrictPushDown

public abstract void restrictPushDown(SelectorImpl s)

Push as much of the condition down to this selector, further restricting the selector condition if possible. This is important for a join: for example, the query "select * from a inner join b on a.x=b.x where a.y=1 and b.y=1", the condition "a.y=1" can be pushed down to "a", and the condition "b.y=1" can be pushed down to "b". That means it is possible to use an index in this case.

Parameters:

s - the selector

equals

public boolean equals(Object other)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

requiresFullTextIndex

public boolean requiresFullTextIndex()

Whether the constraint contains a fulltext condition that requires using a fulltext index, because the condition can only be evaluated there.

Returns:

true if yes

containsUnfilteredFullTextCondition

public boolean containsUnfilteredFullTextCondition()

Whether the condition contains a fulltext condition that can not be applied to the filter, for example because it is part of an "or" condition of the form "where a=1 or contains(., 'x')".

Returns:

true if yes

convertToUnion

@NotNull
public @NotNull Set<ConstraintImpl> convertToUnion()

Compute a set of sub-constraints that could be used for composing UNION statements. For example in case of "c=1 or c=2", it will return to the caller [c=1, c=2]. Those can be later on used for re-composing conditions.

If it is not possible to convert to a union, it must return an empty set.

The default implementation in convertToUnion() always return an empty set.

Returns:

the set of union constraints, if available, or an empty set if conversion is not possible

protect

protected String protect(Object expression)

quote

protected String quote(String pathOrName)

quoteJson

protected String quoteJson(String string)

setQuery

public void setQuery(QueryImpl query)

normalizePropertyName

protected String normalizePropertyName(String propertyName)

Normalize the property name (including namespace remapping). Asterisks are kept.

Parameters:

propertyName - the property name to normalize

Returns:

the normalized (oak-) property name

normalizePath

protected String normalizePath(String path)

Validate and normalize the path.

Parameters:

path - the path to validate

Returns:

the validated and normalized path

convertValueToType

protected PropertyValue convertValueToType(PropertyValue v,
                                           PropertyValue targetType)

getLocalPath

protected String getLocalPath(String path)

Calculate the session local path (the path excluding the workspace name) if possible.

Parameters:

path - the absolute path

Returns:

the session local path, or null if not within this workspace

copyOf

@NotNull
public @NotNull org.apache.jackrabbit.oak.query.ast.AstElement copyOf()

Returns:

a clone of self. Default implementation in AstElement returns same reference to this.