com.wrmsr.wava.util.collect.MoreOptionals.java Source code

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Here is the source code for com.wrmsr.wava.util.collect.MoreOptionals.java

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/*
 * 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.wrmsr.wava.util.collect;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;

import java.util.Arrays;
import java.util.List;
import java.util.Optional;
import java.util.OptionalInt;
import java.util.Set;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.stream.IntStream;
import java.util.stream.Stream;

public final class MoreOptionals {
    private MoreOptionals() {
    }

    public static <T> List<T> optionalToList(Optional<T> o) {
        if (o.isPresent()) {
            return ImmutableList.of(o.get());
        } else {
            return ImmutableList.of();
        }
    }

    public static <T> Set<T> optionalToSet(Optional<T> o) {
        if (o.isPresent()) {
            return ImmutableSet.of(o.get());
        } else {
            return ImmutableSet.of();
        }
    }

    public static <T> Stream<T> optionalToStream(Optional<T> o) {
        if (o.isPresent()) {
            return Stream.of(o.get());
        } else {
            return Stream.empty();
        }
    }

    public static IntStream optionalToStream(OptionalInt o) {
        if (o.isPresent()) {
            return IntStream.of(o.getAsInt());
        } else {
            return IntStream.empty();
        }
    }

    public static <T> Stream<T> optionalsToStream(Optional<T>... os) {
        return Arrays.stream(os).flatMap(MoreOptionals::<T>optionalsToStream);
    }

    @SuppressWarnings({ "unchecked" })
    public static <T> Optional<T> tryCast(Object obj, Class<? extends T> cls) {
        if (cls.isInstance(obj)) {
            return Optional.of((T) obj);
        } else {
            return Optional.empty();
        }
    }

    public static <T> void ifPresentOrElse(Optional<T> optional, Consumer<T> ifPresent, Runnable orElse) {
        if (optional.isPresent()) {
            ifPresent.accept(optional.get());
        } else {
            orElse.run();
        }
    }

    public static <T, R> R ifPresentOrElse(Optional<T> optional, Function<T, R> ifPresent, Supplier<R> orElse) {
        if (optional.isPresent()) {
            return ifPresent.apply(optional.get());
        } else {
            return orElse.get();
        }
    }

    public static <T> void ifNotPresent(Optional<T> optional, Runnable fn) {
        if (!optional.isPresent()) {
            fn.run();
        }
    }
}