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/*
* esodata - data structures and other things, of varying utility
* Copyright 2022, Ben Culkin
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package bjc.data.internals;
import java.util.function.Function;
import java.util.function.UnaryOperator;
import bjc.data.Holder;
import bjc.data.ListHolder;
import bjc.funcdata.ListEx;
/**
* Holds a list, converted into a holder.
*
* @author Ben Culkin
*/
@SuppressWarnings("javadoc")
public class BoundListHolder<ContainedType> implements Holder<ContainedType> {
/* The list of contained holders. */
private final ListEx<Holder<ContainedType>> heldHolders;
/**
* Create a new list of holders.
*
* @param toHold
* The list of holders to, well, hold.
*/
public BoundListHolder(final ListEx<Holder<ContainedType>> toHold) {
heldHolders = toHold;
}
@Override
public <BoundType> Holder<BoundType>
bind(final Function<ContainedType, Holder<BoundType>> binder) {
if (binder == null)
throw new NullPointerException("Binder must not be null");
final ListEx<Holder<BoundType>> boundHolders
= heldHolders.map(containedHolder -> {
return containedHolder.bind(binder);
});
return new BoundListHolder<>(boundHolders);
}
@Override
public <NewType> Function<ContainedType, Holder<NewType>>
lift(final Function<ContainedType, NewType> func) {
if (func == null)
throw new NullPointerException("Function to lift must not be null");
return val -> {
return new ListHolder<>(func.apply(val));
};
}
@Override
public <MappedType> Holder<MappedType>
map(final Function<ContainedType, MappedType> mapper) {
if (mapper == null)
throw new NullPointerException("Mapper must not be null");
final ListEx<Holder<MappedType>> mappedHolders
= heldHolders.map(containedHolder -> {
return containedHolder.map(mapper);
});
return new BoundListHolder<>(mappedHolders);
}
@Override
public Holder<ContainedType>
transform(final UnaryOperator<ContainedType> transformer) {
if (transformer == null)
throw new NullPointerException("Transformer must not be null");
heldHolders.forEach(containedHolder -> {
containedHolder.transform(transformer);
});
return this;
}
@Override
public <UnwrappedType> UnwrappedType
unwrap(final Function<ContainedType, UnwrappedType> unwrapper) {
if (unwrapper == null)
throw new NullPointerException("Unwrapper must not be null");
/*
* @NOTE Is there another way we could want to do this?
*/
return heldHolders.randItem().unwrap(unwrapper);
}
}
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