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// Copyright (C) 2009 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.gerrit.index.query;
import static com.google.common.base.Preconditions.checkState;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
/** Negates the result of another predicate. */
public final class NotPredicate<T> extends Predicate<T> implements Matchable<T> {
private final Predicate<T> that;
NotPredicate(Predicate<T> that) {
if (that instanceof NotPredicate) {
throw new IllegalArgumentException("Double negation unsupported");
}
this.that = that;
}
@Override
public final List<Predicate<T>> getChildren() {
return Collections.singletonList(that);
}
@Override
public final int getChildCount() {
return 1;
}
@Override
public final Predicate<T> getChild(int i) {
if (i != 0) {
throw new ArrayIndexOutOfBoundsException(i);
}
return that;
}
@Override
public Predicate<T> copy(Collection<? extends Predicate<T>> children) {
if (children.size() != 1) {
throw new IllegalArgumentException("Expected exactly one child");
}
return new NotPredicate<>(children.iterator().next());
}
@Override
public boolean isMatchable() {
return that.isMatchable();
}
@Override
public boolean match(T object) {
checkState(
that.isMatchable(),
"match invoked, but child predicate %s doesn't implement %s",
that,
Matchable.class.getName());
return !that.asMatchable().match(object);
}
@Override
public int getCost() {
return that.estimateCost();
}
@Override
public int hashCode() {
return ~that.hashCode();
}
@Override
public boolean equals(Object other) {
if (other == null) {
return false;
}
return other instanceof NotPredicate
&& getChildren().equals(((Predicate<?>) other).getChildren());
}
@Override
public final String toString() {
return "-" + that.toString();
}
}