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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 static com.google.common.collect.ImmutableList.toImmutableList;
import com.google.common.collect.ImmutableList;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
/** Requires all predicates to be true. */
public class AndPredicate<T> extends Predicate<T>
implements Matchable<T>, Comparator<Predicate<T>> {
private final List<Predicate<T>> children;
private final int cost;
@SafeVarargs
protected AndPredicate(Predicate<T>... that) {
this(Arrays.asList(that));
}
protected AndPredicate(Collection<? extends Predicate<T>> that) {
List<Predicate<T>> t = new ArrayList<>(that.size());
int c = 0;
for (Predicate<T> p : sort(that)) {
if (getClass() == p.getClass()) {
for (Predicate<T> gp : p.getChildren()) {
t.add(gp);
c += gp.estimateCost();
}
} else {
t.add(p);
c += p.estimateCost();
}
}
children = t;
cost = c;
}
@Override
public final List<Predicate<T>> getChildren() {
return Collections.unmodifiableList(children);
}
@Override
public final int getChildCount() {
return children.size();
}
@Override
public final Predicate<T> getChild(int i) {
return children.get(i);
}
@Override
public Predicate<T> copy(Collection<? extends Predicate<T>> children) {
return new AndPredicate<>(children);
}
@Override
public boolean isMatchable() {
for (Predicate<T> c : children) {
if (!c.isMatchable()) {
return false;
}
}
return true;
}
@Override
public boolean match(T object) {
for (Predicate<T> c : children) {
checkState(
c.isMatchable(),
"match invoked, but child predicate %s doesn't implement %s",
c,
Matchable.class.getName());
if (!c.asMatchable().match(object)) {
return false;
}
}
return true;
}
@Override
public int getCost() {
return cost;
}
@Override
public int hashCode() {
return getChild(0).hashCode() * 31 + getChild(1).hashCode();
}
// Suppress the EqualsGetClass warning as this is legacy code.
@SuppressWarnings("EqualsGetClass")
@Override
public boolean equals(Object other) {
if (other == null) {
return false;
}
return getClass() == other.getClass()
&& getChildren().equals(((Predicate<?>) other).getChildren());
}
private ImmutableList<Predicate<T>> sort(Collection<? extends Predicate<T>> that) {
return that.stream().sorted(this).collect(toImmutableList());
}
@Override
public int compare(Predicate<T> a, Predicate<T> b) {
int ai = a instanceof DataSource ? 0 : 1;
int bi = b instanceof DataSource ? 0 : 1;
int cmp = ai - bi;
if (cmp == 0) {
cmp = a.estimateCost() - b.estimateCost();
}
if (cmp == 0 && a instanceof DataSource) {
DataSource<?> as = (DataSource<?>) a;
DataSource<?> bs = (DataSource<?>) b;
cmp = as.getCardinality() - bs.getCardinality();
}
return cmp;
}
@Override
public String toString() {
final StringBuilder r = new StringBuilder();
r.append("(");
for (int i = 0; i < getChildCount(); i++) {
if (i != 0) {
r.append(" ");
}
r.append(getChild(i));
}
r.append(")");
return r.toString();
}
}