org.codefilarete.tool.collection.ReadOnlyIterator Maven / Gradle / Ivy
package org.codefilarete.tool.collection;
import java.util.Iterator;
import java.util.function.Consumer;
/**
* A marking class for {@link Iterator} which elements cannot be removed.
*
* @author Guillaume Mary
*/
public abstract class ReadOnlyIterator implements Iterator {
/**
* Simple shortcut to {@link ReadOnlyWrappedIterator#ReadOnlyWrappedIterator(Iterator)}, made because it seems more readable
* at usage than instantiating the class. Totally subjective.
*
* @param iterable the {@link Iterable} that the iterator will be taken on
* @param iterator element type
* @return a new {@link ReadOnlyIterator} wrapping given {@link Iterable} iterator
*/
public static ReadOnlyIterator wrap(Iterable iterable) {
return new ReadOnlyWrappedIterator<>(iterable.iterator());
}
/**
* Simple shortcut to {@link ReadOnlyWrappedIterator#ReadOnlyWrappedIterator(Iterator)}, made because it seems more readable
* at usage than instantiating the class. Totally subjective.
*
* @param iterator the wrapped iterator
* @param iterator element type
* @return a new {@link ReadOnlyIterator} wrapping given {@link Iterator}
*/
public static ReadOnlyIterator wrap(Iterator iterator) {
return new ReadOnlyWrappedIterator<>(iterator);
}
/** Overridden to mark it final */
@Override
public final void remove() {
throw new UnsupportedOperationException();
}
private static class ReadOnlyWrappedIterator extends ReadOnlyIterator {
private final Iterator surrogate;
public ReadOnlyWrappedIterator(Iterator surrogate) {
this.surrogate = surrogate;
}
@Override
public boolean hasNext() {
return surrogate.hasNext();
}
@Override
public C next() {
return surrogate.next();
}
@Override
public void forEachRemaining(Consumer action) {
surrogate.forEachRemaining(action);
}
}
}