Collapse Maybe{Optional,Stream} into Maybe
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7a150066a9
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3 changed files with 62 additions and 134 deletions
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@ -24,7 +24,12 @@ package net.kemitix.mon.maybe;
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import lombok.NonNull;
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import lombok.NonNull;
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import net.kemitix.mon.Functor;
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import net.kemitix.mon.Functor;
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import java.util.Optional;
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import java.util.function.Consumer;
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import java.util.function.Function;
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import java.util.function.Function;
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import java.util.function.Predicate;
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import java.util.function.Supplier;
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import java.util.stream.Stream;
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/**
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/**
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* A value that may or may not be present.
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* A value that may or may not be present.
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@ -32,7 +37,8 @@ import java.util.function.Function;
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* @param <T> the type of the content of the Just
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* @param <T> the type of the content of the Just
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* @author Paul Campbell (pcampbell@kemitix.net)
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* @author Paul Campbell (pcampbell@kemitix.net)
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*/
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*/
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public interface Maybe<T> extends Functor<T, Maybe<?>>, MaybeStream<T>, MaybeOptional<T> {
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@SuppressWarnings("methodcount")
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public interface Maybe<T> extends Functor<T, Maybe<?>> {
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/**
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/**
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* Create a Maybe for the value that may or may not be present.
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* Create a Maybe for the value that may or may not be present.
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@ -72,4 +78,59 @@ public interface Maybe<T> extends Functor<T, Maybe<?>>, MaybeStream<T>, MaybeOpt
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@Override
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@Override
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<R> Maybe<R> map(Function<T, R> f);
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<R> Maybe<R> map(Function<T, R> f);
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/**
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* Provide a value to use when Maybe is Nothing.
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*
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* @param supplier supplier for an alternate value
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* @return a Maybe
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*/
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T orElseGet(Supplier<T> supplier);
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/**
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* A value to use when Maybe is Nothing.
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*
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* @param otherValue an alternate value
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* @return a Maybe
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*/
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T orElse(T otherValue);
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/**
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* Convert the Maybe to an {@link Optional}.
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*
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* @return an Optional containing a value for a Just, or empty for a Nothing
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*/
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Optional<T> toOptional();
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/**
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* Throw the exception if the Maybe is a Nothing.
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*
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* @param e the exception to throw
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* @throws Exception if the Maybe is a Nothing
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*/
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@SuppressWarnings("illegalthrows")
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void orElseThrow(Supplier<Exception> e) throws Exception;
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/**
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* Converts the Maybe into either a single value stream or and empty stream.
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*
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* @return a Stream containing the value or nothing.
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*/
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Stream<T> stream();
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/**
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* Filter a Maybe by the predicate, replacing with Nothing when it fails.
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*
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* @param predicate the test
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* @return the Maybe, or Nothing if the test returns false
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*/
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Maybe<T> filter(Predicate<T> predicate);
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/**
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* Provide the value within the Maybe, if it exists, to the Supplier, and returns the Maybe.
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*
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* @param consumer the Consumer to the value if present
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* @return the Maybe
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*/
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Maybe<T> peek(Consumer<T> consumer);
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}
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}
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@ -1,71 +0,0 @@
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/**
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* The MIT License (MIT)
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*
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* Copyright (c) 2017 Paul Campbell
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of this software
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* and associated documentation files (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all copies
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* or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
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* AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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package net.kemitix.mon.maybe;
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import java.util.Optional;
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import java.util.function.Supplier;
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/**
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* Enables emulation parts of and conversion to the Java Optional class for Maybe.
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*
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* @param <T> the type of the content of the Just
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*
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* @author Paul Campbell (pcampbell@kemitix.net)
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*/
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interface MaybeOptional<T> {
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/**
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* Provide a value to use when Maybe is Nothing.
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*
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* @param supplier supplier for an alternate value
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*
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* @return a Maybe
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*/
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T orElseGet(Supplier<T> supplier);
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/**
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* A value to use when Maybe is Nothing.
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*
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* @param otherValue an alternate value
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*
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* @return a Maybe
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*/
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T orElse(T otherValue);
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/**
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* Convert the Maybe to an {@link Optional}.
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*
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* @return an Optional containing a value for a Just, or empty for a Nothing
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*/
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Optional<T> toOptional();
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/**
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* Throw the exception if the Maybe is a Nothing.
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*
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* @param e the exception to throw
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*
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* @throws Exception if the Maybe is a Nothing
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*/
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@SuppressWarnings("illegalthrows")
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void orElseThrow(Supplier<Exception> e) throws Exception;
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}
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@ -1,62 +0,0 @@
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/**
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* The MIT License (MIT)
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*
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* Copyright (c) 2017 Paul Campbell
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of this software
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* and associated documentation files (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all copies
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* or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
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* AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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package net.kemitix.mon.maybe;
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import java.util.function.Consumer;
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import java.util.function.Predicate;
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import java.util.stream.Stream;
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/**
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* Enables emulation parts of and conversion to the Java Stream class for Maybe.
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*
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* @param <T> the type of the content of the Just
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*
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* @author Paul Campbell (pcampbell@kemitix.net)
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*/
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interface MaybeStream<T> {
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/**
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* Converts the Maybe into either a single value stream or and empty stream.
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*
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* @return a Stream containing the value or nothing.
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*/
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Stream<T> stream();
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/**
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* Filter a Maybe by the predicate, replacing with Nothing when it fails.
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*
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* @param predicate the test
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*
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* @return the Maybe, or Nothing if the test returns false
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*/
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Maybe<T> filter(Predicate<T> predicate);
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/**
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* Provide the value within the Maybe, if it exists, to the Supplier, and returns the Maybe.
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*
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* @param consumer the Consumer to the value if present
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*
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* @return the Maybe
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*/
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Maybe<T> peek(Consumer<T> consumer);
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}
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