net.sf.staccatocommons.iterators.PrependThriterator Maven / Gradle / Ivy
/**
* Copyright (c) 2010-2012, The StaccatoCommons Team
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; version 3 of the License.
*
* 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 Lesser General Public License for more details.
*/
package net.sf.staccatocommons.iterators;
import java.util.Iterator;
import java.util.NoSuchElementException;
import net.sf.staccatocommons.defs.Thunk;
import net.sf.staccatocommons.iterators.thriter.AdvanceThriterator;
import net.sf.staccatocommons.iterators.thriter.Thriter;
import net.sf.staccatocommons.iterators.thriter.Thriterator;
import net.sf.staccatocommons.iterators.thriter.Thriterators;
import net.sf.staccatocommons.iterators.thriter.internal.ConstantThunk;
/**
* @author flbulgarelli
*
*/
public class PrependThriterator extends AdvanceThriterator {
private final A element;
private final Thriter iter;
private boolean elementConsumed;
private boolean iterAdvanced;
/**
* Creates a new {@link PrependThriterator}
*/
public PrependThriterator(A element, Thriter iterator) {
this.element = element;
this.iter = iterator;
}
/**
* Creates a new {@link PrependThriterator}
*/
public PrependThriterator(A element, Iterator iterator) {
this(element, (Thriter) Thriterators.from(iterator));
}
/**
* Creates a new {@link PrependThriterator}
*/
public PrependThriterator(A element, Thriterator iterator) {
this(element, (Thriter) iterator);
}
public final boolean hasNext() {
return !elementConsumed || iter.hasNext();
}
public final void advanceNext() throws NoSuchElementException {
if (!elementConsumed) {
elementConsumed = true;
} else {
iter.advanceNext();
iterAdvanced = true;
}
}
public final A current() throws NoSuchElementException {
if (iterAdvanced)
return iter.current();
return elementValue();
}
protected A elementValue() {
return element;
}
protected Thunk elementThunk() {
return new ConstantThunk(element);
}
public Thunk delayedCurrent() {
if (iterAdvanced)
return (Thunk) iter.delayedCurrent();
return elementThunk();
}
}