/**
* Copyright 2004-2016 Riccardo Solmi. All rights reserved.
* This file is part of the Whole Platform.
*
* The Whole Platform 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, either version 3 of the License, or
* (at your option) any later version.
*
* The Whole Platform 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.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the Whole Platform. If not, see <http://www.gnu.org/licenses/>.
*/
package org.whole.lang.iterators;
import java.util.ArrayList;
import java.util.List;
import org.whole.lang.bindings.IBindingScope;
import org.whole.lang.bindings.NullScope;
import org.whole.lang.model.IEntity;
import org.whole.lang.operations.ICloneContext;
/**
* @author Riccardo Solmi
*/
public abstract class AbstractTransitiveClosureIterator<E extends IEntity> extends AbstractCloneableIterator<E> {
protected List<IEntityIterator<E>> iteratorStack = new ArrayList<IEntityIterator<E>>(16);
protected IEntityIterator<E> lastIterator;
protected E lastEntity;
protected boolean includeSelf;
protected AbstractTransitiveClosureIterator(boolean includeSelf) {
this.includeSelf = includeSelf;
}
@Override
public IEntityIterator<E> clone(ICloneContext cc) {
AbstractTransitiveClosureIterator<E> iterator = (AbstractTransitiveClosureIterator<E>) super.clone(cc);
if (iteratorStack != null) {
iterator.iteratorStack = new ArrayList<IEntityIterator<E>>(iteratorStack.size());
for (int i=0,size=iteratorStack.size(); i<size; i++) {
IEntityIterator<E> isClone = cc.clone(iteratorStack.get(i));
iterator.iteratorStack.add(isClone);
if (iteratorStack.get(i) == lastIterator)
iterator.lastIterator = isClone;
}
}
return iterator;
}
protected IEntityIterator<E> peekIterator() {
return iteratorStack.get(iteratorStack.size()-1);
}
protected final void pushIterator(IEntityIterator<E> iterator, IEntity entity) {
iterator.setBindings(getBindings());
iterator.reset(entity);
iteratorStack.add(iterator);
}
protected final IEntityIterator<E> popIterator() {
return iteratorStack.remove(iteratorStack.size()-1);
}
protected IEntityIterator<E> currentIterator() {
IEntityIterator<E> result;
while (!(result = peekIterator()).hasNext() && iteratorStack.size()>1)
popIterator();
return result;
}
protected void pushInitialIterators(IEntity entity) {
pushIterator(includeSelf ?
IteratorFactory.<E>selfIterator() : createRelationIterator(), entity);
}
protected boolean isRelationNotEmpty(IEntity entity) {
return entity.wSize() > 0;
}
protected IEntityIterator<E> createRelationIterator() {
return IteratorFactory.<E>childIterator();
}
public IBindingScope lookaheadScope() {
return NullScope.instance;
}
public void reset(IEntity entity) {
lastEntity = null;
lastIterator = null;
iteratorStack.clear();
pushInitialIterators(entity);
}
public boolean hasNext() {
return currentIterator().hasNext();
}
public E next() {
lastIterator = currentIterator();
E entity = lastIterator.next();
if (isRelationNotEmpty(entity))
pushIterator(createRelationIterator(), entity);
return lastEntity = entity;
}
public E lookahead() {
return currentIterator().lookahead();
}
public void prune() {
for (int i=iteratorStack.size()-1; i>=0; i--)
if (iteratorStack.get(i) == lastIterator) {
while (iteratorStack.size()-1 > i)
popIterator();
return;
}
}
public void set(E value) {
if (lastEntity == null)
throw new IllegalStateException();
lastIterator.set(value);
}
public void add(E value) {
lastIterator.add(value);
}
public void remove() {
if (lastEntity == null)
throw new IllegalStateException();
prune();
lastIterator.remove();
lastEntity = null;
lastIterator = null;
}
public abstract void toString(StringBuilder sb);
}