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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.funcdata;
import java.util.*;
import java.util.function.*;
/**
* A map that transforms values from one type to another
*
* @author ben
*
* @param <OldKey>
* The type of the map's keys
*
* @param <OldValue>
* The type of the map's values
*
* @param <NewValue>
* The type of the transformed values
*
*/
final class TransformedValueMap<OldKey, OldValue, NewValue>
implements MapEx<OldKey, NewValue> {
/* Our backing map. */
private final MapEx<OldKey, OldValue> backing;
/* Our transforming function. */
private final Function<OldValue, NewValue> transformer;
private boolean isFrozen = false;
private boolean thawEnabled = true;
/**
* Create a new transformed-value loop.
*
* @param backingMap
* The map to use as backing.
*
* @param transform
* The function to use for the transform.
*/
public TransformedValueMap(final MapEx<OldKey, OldValue> backingMap,
final Function<OldValue, NewValue> transform) {
backing = backingMap;
transformer = transform;
}
@Override
public void clear() {
if (isFrozen) throw new ObjectFrozen("Can't clear frozen map");
backing.clear();
}
@Override
public boolean containsKey(final OldKey key) {
return backing.containsKey(key);
}
@Override
public void forEach(final BiConsumer<OldKey, NewValue> action) {
backing.forEach((key, value) -> {
action.accept(key, transformer.apply(value));
});
}
@Override
public Optional<NewValue> get(final OldKey key) {
return backing.get(key).map(transformer);
}
@Override
public int size() {
return backing.size();
}
@Override
public ListEx<OldKey> keyList() {
return backing.keyList();
}
@Override
public NewValue put(final OldKey key, final NewValue value) {
throw new UnsupportedOperationException("Can't add items to transformed map");
}
@Override
public NewValue remove(final OldKey key) {
if (isFrozen) throw new ObjectFrozen("Can't remove key " + key + " from frozen map");
return transformer.apply(backing.remove(key));
}
@Override
public String toString() {
return backing.toString();
}
@Override
public boolean freeze() {
isFrozen = true;
return true;
}
@Override
public boolean thaw() {
if (thawEnabled) {
isFrozen = false;
return true;
} else {
return false;
}
}
@Override
public boolean deepFreeze() {
thawEnabled = false;
return freeze();
}
@Override
public boolean canFreeze() {
return true;
}
@Override
public boolean canThaw() {
return thawEnabled;
}
@Override
public boolean isFrozen() {
return isFrozen;
}
}
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