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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.objects;
/**
* A node in a traversable tree.
* Every non leaf Object implements {@link #selectMembers(ObjectPredicate, ObjectOperation)} implementing
* the actual traversal. You can then implement an {@link ObjectPredicate} to select which nodes you want to look at with
* your {@link ObjectOperation}
*
* @author baldersheim
*/
public class Selectable {
/**
* Applies the predicate to this object. If the predicate returns true, pass this object to the operation, otherwise
* invoke the {@link #selectMembers(ObjectPredicate, ObjectOperation)} method to locate sub-elements that might
* trigger the predicate.
*
* @param predicate component used to select (sub-)objects
* @param operation component performing some operation on the selected (sub-)objects
*/
public final void select(ObjectPredicate predicate, ObjectOperation operation) {
if (predicate.check(this)) {
operation.execute(this);
} else {
selectMembers(predicate, operation);
}
}
/**
* Invokes {@link #select(ObjectPredicate, ObjectOperation)} on any member objects this object wants to expose
* through the selection mechanism. Overriding this method is optional, and which objects to expose is determined by
* the application logic of the object itself.
*
* @param predicate component used to select (sub-)objects
* @param operation component performing some operation on the selected (sub-)objects
*/
public void selectMembers(ObjectPredicate predicate, ObjectOperation operation) {
// empty
}
public static void select(Selectable selectable, ObjectPredicate predicate, ObjectOperation operation) {
if (selectable != null) {
selectable.select(predicate, operation);
}
}
}
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