org.polarsys.reqcycle.utils.iterators.collectors.WidthHarvester.java Source code

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Here is the source code for org.polarsys.reqcycle.utils.iterators.collectors.WidthHarvester.java

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/*******************************************************************************
 * Copyright (c) 2013 Atos.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     Atos - initial API and implementation
 ******************************************************************************/
package org.polarsys.reqcycle.utils.iterators.collectors;

import java.util.Collections;

import org.polarsys.reqcycle.utils.iterators.Activator;
import org.polarsys.reqcycle.utils.iterators.exceptions.CannotHandleException;
import org.polarsys.reqcycle.utils.iterators.exceptions.CollectionAbortedException;
import org.polarsys.reqcycle.utils.iterators.handlers.ResultHandler;
import org.polarsys.reqcycle.utils.iterators.pickers.IPicker;

import com.google.common.collect.Iterables;

public class WidthHarvester extends Harvester {

    public WidthHarvester(Object startingElement) {
        super(startingElement);
    }

    public void collect(ResultHandler<Object> handler) throws CollectionAbortedException {
        collectWidthWise(handler, start);
    }

    /**
     * Width wise collection.
     * 
     * @param handler
     *            the handler that processes each element.
     * @param element
     *            : the element from which the collection is performed.
     * @throws CollectionAbortedException
     */
    protected void collectWidthWise(ResultHandler<Object> handler, Object element)
            throws CollectionAbortedException {
        Iterable<?> currentLayer = Collections.singletonList(element);
        Iterable<?> nextLayer = Collections.EMPTY_LIST;
        while (currentLayer != null && !Iterables.isEmpty(currentLayer)) {
            for (Object currentElement : currentLayer) {
                try {
                    handler.handleResult(currentElement);
                    // Building the next layer.
                    for (IPicker picker : this.getPickers()) {
                        Iterable<?> nexts = picker.getNexts(currentElement); // getting children.
                        if (nexts != null) {
                            nextLayer = Iterables.concat(nextLayer, nexts);
                        }
                    }
                } catch (CannotHandleException e) {
                    // do nothing
                } catch (Exception e) {
                    Activator.logError(e);
                }
            }
            // The current layer has been processed. Going through the next one.
            currentLayer = nextLayer;
            nextLayer = Collections.EMPTY_LIST;
        }
    }

}