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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.prelude.query;
import java.util.Optional;
/**
* A composite item which specifies semantics which are not maintained
* if an instance with a single child is replaced by the single child.
* Most composites, like AND and OR, are reducible as e.g (AND a) is semantically equal to (a).
* This type functions as a marker type for query rewriters.
*
* @author bratseth
*/
public abstract class NonReducibleCompositeItem extends CompositeItem {
@Override
public Optional<Item> extractSingleChild() {
return Optional.empty();
}
}
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