Package org.openrewrite

Class TreeVisitor<T extends Tree,P>

java.lang.Object

org.openrewrite.TreeVisitor<T,P>

Type Parameters:

T - The type of tree.

P - An input object that is passed to every visit method.

Direct Known Subclasses:

BinaryVisitor, CreateFileVisitor, FindRecipeRunException, ParseErrorVisitor, PlainTextVisitor, Preconditions.Check, QuarkVisitor, RemoteVisitor

public abstract class TreeVisitor<T extends Tree,P>
extends Object

Abstract TreeVisitor for processing elements

Always returns input type T provides Parameterizable P input which is mutable allowing context to be shared

postProcessing via afterVisit for conditionally chaining other operations with the expectation is that after TreeVisitors are invoked immediately after visiting SourceFile

Constructor Summary

Constructors

Constructor	Description
TreeVisitor()

Method Summary

Modifier and Type	Method	Description
<R extends Tree, V extends TreeVisitor<R, P>> V	adapt(Class<? extends V> adaptTo)
static <R extends Tree, C extends Collection<R>> C	collect(TreeVisitor<?,ExecutionContext> visitor, Tree tree, C initial)
static <U extends Tree, R, C extends Collection<R>> C	collect(TreeVisitor<?,ExecutionContext> visitor, Tree tree, C initial, Class<U> matchOn, Function<U,R> map)
T	defaultValue(@Nullable Tree tree, P p)
protected void	doAfterVisit(TreeVisitor<?,P> visitor)	Execute the visitor once after the whole source file has been visited.
protected List<TreeVisitor<?,P>>	getAfterVisit()
final Cursor	getCursor()
@Nullable String	getLanguage()
boolean	isAcceptable(SourceFile sourceFile, P p)
boolean	isAdaptableTo(Class<? extends TreeVisitor> adaptTo)
static <T extends Tree, P> TreeVisitor<T,P>	noop()
T	postVisit(T tree, P p)
T	preVisit(T tree, P p)
P	reduce(Iterable<? extends Tree> trees, P p)
P	reduce(Tree tree, P p)
P	reduce(Tree tree, P p, Cursor parent)
void	setCursor(@Nullable Cursor cursor)
void	stopAfterPreVisit()	Can be used in preVisit(Tree, Object) to prevent a call to visit(Tree, Object) and postVisit(Tree, Object), therefore stopping further navigation deeper down the tree.
final Cursor	updateCursor(T currentValue)	Updates the cursor on this visitor and returns the updated cursor.
void	visit(@Nullable List<? extends T> nodes, P p)
T	visit(@Nullable Tree tree, P p)
T	visit(@Nullable Tree tree, P p, Cursor parent)
protected final <T2 extends T> T2	visitAndCast(@Nullable Tree tree, P p)
protected final <T2 extends Tree> T2	visitAndCast(T2 t, P p, BiFunction<T2,P,Tree> callSuper)
<M extends Marker> M	visitMarker(Marker marker, P p)
Markers	visitMarkers(@Nullable Markers markers, P p)
T	visitNonNull(Tree tree, P p)	By calling this method, you are asserting that you know that the outcome will be non-null when the compiler couldn't otherwise prove this to be the case.
T	visitNonNull(Tree tree, P p, Cursor parent)
protected Class<? extends Tree>	visitorTreeType(Class<? extends TreeVisitor> v)

Methods inherited from class java.lang.Object

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

Constructor Details

TreeVisitor

public TreeVisitor()

Method Details

noop

public static <T extends Tree,
P> TreeVisitor<T,P> noop()

isAcceptable

public boolean isAcceptable(SourceFile sourceFile,
 P p)

setCursor

public void setCursor(@Nullable
 @Nullable Cursor cursor)

getLanguage

@Nullable
public @Nullable String getLanguage()

Returns:

Describes the language type that this visitor applies to, e.g. java, xml, properties.

doAfterVisit

protected void doAfterVisit(TreeVisitor<?,P> visitor)

Execute the visitor once after the whole source file has been visited. The visitor is executed against the whole source file. This operation only happens once immediately after the containing visitor visits the whole source file. A subsequent Recipe cycle will not run it.

This method is ideal for one-off operations like auto-formatting, adding/removing imports, etc.

Parameters:

visitor - The visitor to run.

getAfterVisit

protected List<TreeVisitor<?,P>> getAfterVisit()

getCursor

public final Cursor getCursor()

updateCursor

public final Cursor updateCursor(T currentValue)

Updates the cursor on this visitor and returns the updated cursor.

Parameters:

currentValue - The new (current) value of the cursor based on a mutation of what was formerly the Cursor.getValue().

Returns:

The updated cursor.

preVisit

@Nullable
public T preVisit(T tree,
 P p)

postVisit

@Nullable
public T postVisit(T tree,
 P p)

visit

@Nullable
public T visit(@Nullable
 @Nullable Tree tree,
 P p,
 Cursor parent)

visitNonNull

public T visitNonNull(Tree tree,
 P p)

By calling this method, you are asserting that you know that the outcome will be non-null when the compiler couldn't otherwise prove this to be the case. This method is a shortcut for having to assert the non-nullability of the returned tree.

Parameters:

tree - A non-null tree.

p - A state object that passes through the visitor.

Returns:

A non-null tree.

visitNonNull

public T visitNonNull(Tree tree,
 P p,
 Cursor parent)

collect

@Incubating(since="7.31.0")
public static <R extends Tree,
C extends Collection<R>>
C collect(TreeVisitor<?,ExecutionContext> visitor,
 Tree tree,
 C initial)

collect

@Incubating(since="7.31.0")
public static <U extends Tree,
R,
C extends Collection<R>>
C collect(TreeVisitor<?,ExecutionContext> visitor,
 Tree tree,
 C initial,
 Class<U> matchOn,
 Function<U,R> map)

reduce

@Incubating(since="7.31.0")
public P reduce(Iterable<? extends Tree> trees,
 P p)

reduce

@Incubating(since="7.31.0")
public P reduce(Tree tree,
 P p)

reduce

@Incubating(since="7.31.0")
public P reduce(Tree tree,
 P p,
 Cursor parent)

visit

@Nullable
public T visit(@Nullable
 @Nullable Tree tree,
 P p)

visit

public void visit(@Nullable
 @Nullable List<? extends T> nodes,
 P p)

defaultValue

@Nullable
public T defaultValue(@Nullable
 @Nullable Tree tree,
 P p)

visitAndCast

@Incubating(since="7.0.0")
protected final <T2 extends Tree> T2 visitAndCast(T2 t,
 P p,
 BiFunction<T2,P,Tree> callSuper)

visitAndCast

@Incubating(since="7.0.0")
@Nullable
protected final <T2 extends T> T2 visitAndCast(@Nullable
 @Nullable Tree tree,
 P p)

visitMarkers

public Markers visitMarkers(@Nullable
 @Nullable Markers markers,
 P p)

visitMarker

public <M extends Marker> M visitMarker(Marker marker,
 P p)

isAdaptableTo

public boolean isAdaptableTo(Class<? extends TreeVisitor> adaptTo)

visitorTreeType

protected Class<? extends Tree> visitorTreeType(Class<? extends TreeVisitor> v)

adapt

public <R extends Tree,
V extends TreeVisitor<R,
P>>
V adapt(Class<? extends V> adaptTo)

stopAfterPreVisit

@Incubating(since="8.0.0")
public void stopAfterPreVisit()

Can be used in preVisit(Tree, Object) to prevent a call to visit(Tree, Object) and postVisit(Tree, Object), therefore stopping further navigation deeper down the tree.