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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.brooklyn.util.collections;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
import org.apache.brooklyn.util.collections.QuorumCheck.QuorumChecks;
import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.base.Supplier;
import com.google.common.collect.Iterables;
import com.google.common.collect.Sets;
/** things which it seems should be in guava, but i can't find
* @author alex */
public class CollectionFunctionals {
private static final class EqualsSetPredicate implements Predicate> {
private final Iterable target;
private EqualsSetPredicate(Iterable target) {
this.target = target;
}
@Override
public boolean apply(@Nullable Iterable input) {
if (input==null) return false;
return Sets.newHashSet(target).equals(Sets.newHashSet(input));
}
}
private static final class KeysOfMapFunction implements Function, Set> {
@Override
public Set apply(Map input) {
if (input==null) return null;
return input.keySet();
}
@Override public String toString() { return "keys"; }
}
private static final class SizeSupplier implements Supplier {
private final Iterable collection;
private SizeSupplier(Iterable collection) {
this.collection = collection;
}
@Override
public Integer get() {
return Iterables.size(collection);
}
@Override public String toString() { return "sizeSupplier("+collection+")"; }
}
public static final class SizeFunction implements Function, Integer> {
private final Integer valueIfInputNull;
private SizeFunction(Integer valueIfInputNull) {
this.valueIfInputNull = valueIfInputNull;
}
@Override
public Integer apply(Iterable input) {
if (input==null) return valueIfInputNull;
return Iterables.size(input);
}
@Override public String toString() { return "sizeFunction"; }
}
public static Supplier sizeSupplier(final Iterable collection) {
return new SizeSupplier(collection);
}
public static Function, Integer> sizeFunction() { return sizeFunction(null); }
public static Function, Integer> sizeFunction(final Integer valueIfInputNull) {
return new SizeFunction(valueIfInputNull);
}
public static final class FirstElementFunction implements Function, T> {
public FirstElementFunction() {
}
@Override
public T apply(Iterable input) {
if (input==null || Iterables.isEmpty(input)) return null;
return Iterables.get(input, 0);
}
@Override public String toString() { return "firstElementFunction"; }
}
public static Function, T> firstElement() {
return new FirstElementFunction();
}
public static Function,Set> keys() {
return new KeysOfMapFunction();
}
public static Function, Integer> mapSize() {
return mapSize(null);
}
public static Function, Integer> mapSize(Integer valueIfNull) {
return Functions.compose(CollectionFunctionals.sizeFunction(valueIfNull), CollectionFunctionals.keys());
}
/** default guava Equals predicate will reflect order of target, and will fail when matching against a list;
* this treats them both as sets */
public static Predicate> equalsSetOf(Object... target) {
return equalsSet(Arrays.asList(target));
}
public static Predicate> equalsSet(final Iterable target) {
return new EqualsSetPredicate(target);
}
public static Predicate> sizeEquals(int targetSize) {
return Predicates.compose(Predicates.equalTo(targetSize), CollectionFunctionals.sizeFunction());
}
public static Predicate> empty() {
return sizeEquals(0);
}
public static Predicate> notEmpty() {
return Predicates.not(empty());
}
public static Predicate> mapSizeEquals(int targetSize) {
return Predicates.compose(Predicates.equalTo(targetSize), CollectionFunctionals.mapSize());
}
public static > Function> limit(final int max) {
return new LimitFunction(max);
}
private static final class LimitFunction> implements Function> {
private final int max;
private LimitFunction(int max) {
this.max = max;
}
@Override
public List apply(I input) {
if (input==null) return null;
MutableList result = MutableList.of();
for (T i: input) {
result.add(i);
if (result.size()>=max)
return result;
}
return result;
}
}
// ---------
public static > Predicate contains(I item) {
return new CollectionContains(item);
}
private static final class CollectionContains> implements Predicate {
private final I item;
private CollectionContains(I item) {
this.item = item;
}
@Override
public boolean apply(T input) {
if (input==null) return false;
return input.contains(item);
}
@Override
public String toString() {
return "contains("+item+")";
}
}
// ---------
/**
* Returns a predicate for a collection which is true if
* all elements in the collection given to the predicate
* which satisfies the predicate given here.
*
* This will return true for the empty set.
* To require additionally that there is at least one
* use {@link #quorum(QuorumCheck, Predicate)} with
* {@link QuorumChecks#allAndAtLeastOne()}. */
public static > Predicate all(Predicate attributeSatisfies) {
return quorum(QuorumChecks.all(), attributeSatisfies);
}
/** Returns a predicate for a collection which is true if
* there is at least one element in the collection given to the predicate
* which satisfies the predicate given here.
*/
public static > Predicate any(Predicate attributeSatisfies) {
// implementation could be more efficient -- ie succeed fast
return quorum(QuorumChecks.atLeastOne(), attributeSatisfies);
}
/** Returns a predicate for a collection which is true if
* the number of elements in the collection satisfying the predicate given here
* passes the {@link QuorumCheck} given here.
*/
public static > Predicate quorum(QuorumCheck quorumCheck, Predicate attributeSatisfies) {
return new QuorumSatisfies(quorumCheck, attributeSatisfies);
}
private static final class QuorumSatisfies> implements Predicate {
private final Predicate itemCheck;
private final QuorumCheck quorumCheck;
private QuorumSatisfies(QuorumCheck quorumCheck, Predicate itemCheck) {
this.itemCheck = Preconditions.checkNotNull(itemCheck, "itemCheck");
this.quorumCheck = Preconditions.checkNotNull(quorumCheck, "quorumCheck");
}
@Override
public boolean apply(T input) {
if (input==null) return false;
int sizeHealthy = 0, totalSize = 0;
for (I item: input) {
totalSize++;
if (itemCheck.apply(item)) sizeHealthy++;
}
return quorumCheck.isQuorate(sizeHealthy, totalSize);
}
@Override
public String toString() {
return quorumCheck.toString()+"("+itemCheck+")";
}
}
}