com.google.gerrit.server.query

Class QueryRewriter<T>

java.lang.Object

com.google.gerrit.server.query.QueryRewriter<T>

Type Parameters:

T - type of object the predicate can evaluate in memory.

Direct Known Subclasses:

BasicChangeRewrites

public abstract class QueryRewriter<T>
extends java.lang.Object

Rewrites a Predicate tree by applying rewrite rules.

Subclasses may document their rewrite rules by declaring public methods with QueryRewriter.Rewrite annotations, such as:

 @Rewrite("A=(owner:*) B=(status:*)")
 public Predicate r1_ownerStatus(@Named("A") OperatorPredicate owner,
     @Named("B") OperatorPredicate status) {
 }
 

Rewrite methods are applied in order by declared name, so naming methods with a numeric prefix to ensure a specific ordering (if required) is suggested.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	QueryRewriter.Definition<T,R extends QueryRewriter<T>> Defines the rewrite rules known by a QueryRewriter.
protected static interface	QueryRewriter.NoCostComputation
protected static interface	QueryRewriter.Rewrite Denotes a method which wants to replace a predicate expression.
protected static interface	QueryRewriter.RewriteRule<T> Applies a rewrite rule to a Predicate.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	QueryRewriter(QueryRewriter.Definition<T,? extends QueryRewriter<T>> def)

Method Summary

Modifier and Type	Method and Description
Predicate<T>	and(java.util.Collection<? extends Predicate<T>> that) Combine the passed predicates into a single AND node.
Predicate<T>	and(Predicate<T>... that) Combine the passed predicates into a single AND node.
Predicate<T>	not(Predicate<T> that) Invert the passed node.
Predicate<T>	or(java.util.Collection<? extends Predicate<T>> that) Combine the passed predicates into a single OR node.
Predicate<T>	or(Predicate<T>... that) Combine the passed predicates into a single OR node.
protected Predicate<T>	preRewrite(Predicate<T> in)
protected Predicate<T>	replaceGenericNodes(Predicate<T> in)
Predicate<T>	rewrite(Predicate<T> in) Apply rewrites to a graph until it stops changing.

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryRewriter

protected QueryRewriter(QueryRewriter.Definition<T,? extends QueryRewriter<T>> def)

Method Detail

and

public Predicate<T> and(java.util.Collection<? extends Predicate<T>> that)

Combine the passed predicates into a single AND node.

and

public Predicate<T> and(Predicate<T>... that)

Combine the passed predicates into a single AND node.

or

public Predicate<T> or(java.util.Collection<? extends Predicate<T>> that)

Combine the passed predicates into a single OR node.

or

public Predicate<T> or(Predicate<T>... that)

Combine the passed predicates into a single OR node.

not

public Predicate<T> not(Predicate<T> that)

Invert the passed node.

preRewrite

protected Predicate<T> preRewrite(Predicate<T> in)

rewrite

public final Predicate<T> rewrite(Predicate<T> in)

Apply rewrites to a graph until it stops changing.

Parameters:

in - the graph to rewrite.

Returns:

the rewritten graph.

replaceGenericNodes

protected Predicate<T> replaceGenericNodes(Predicate<T> in)