org.polarsys.reqcycle.utils.iterators.pickers.ArcPicker.java Source code

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Here is the source code for org.polarsys.reqcycle.utils.iterators.pickers.ArcPicker.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.pickers;

import java.util.List;

import org.polarsys.reqcycle.utils.iterators.exceptions.PickerExecutionException;

import com.google.common.collect.Lists;

/**
 * Decorator for a picker : a picker
 */
public class ArcPicker implements IArcPicker {

    protected IPicker basicPicker;

    public ArcPicker(IPicker picker) {
        basicPicker = picker;
    }

    public Iterable<?> getNexts(Object element) throws PickerExecutionException {
        List<IArc> result = Lists.newLinkedList();
        if (element instanceof IArc) {
            IArc arc = (IArc) element;
            // Getting the destination of the arc : the nexts are
            // the arcs starting from the destination.
            Object destination = arc.getDestination();
            Iterable<?> nexts = basicPicker.getNexts(destination);
            if (nexts != null) {
                for (Object child : nexts) {
                    IArc arcChild = new PickableArc(basicPicker, arc, destination, child);
                    result.add(arcChild);
                }
            }
        }
        return result;
    }

    public IPicker getBasePicker() {
        return this.basicPicker;
    }

    /**
     * Implementation of arc that ensures that arcs generated by two different pickers are different.
     */
    protected class PickableArc implements IPickableArc {

        private Object origin;

        private Object destination;

        private IPicker picker;

        /**
         * The arc this arc was generated from. HAS NO INFLUENCE ON THE EQUALITY OF ARCS.
         */
        private IArc parentArc;

        public PickableArc(IPicker picker, IArc parentArc, Object origin, Object destination) {
            this.picker = picker;
            this.origin = origin;
            this.destination = destination;
            this.parentArc = parentArc;
        }

        public Object getOrigin() {
            return origin;
        }

        public Object getDestination() {
            return destination;
        }

        public IPicker getPicker() {
            return picker;
        }

        public IArc getParentArc() {
            return parentArc;
        }

        /**
         * Checks that all attributes are equal between the two objects.
         */
        @Override
        public boolean equals(Object arg0) {
            if (arg0 instanceof PickableArc) {
                PickableArc arc = (PickableArc) arg0;
                boolean sameOrigin = false;
                if (getOrigin() != null && arc.getOrigin() != null) {
                    sameOrigin = this.getOrigin().equals(arc.getOrigin());
                } else {
                    sameOrigin = (getOrigin() == null && arc.getOrigin() == null);
                }
                boolean sameDestination = false;
                if (getDestination() != null && arc.getDestination() != null) {
                    sameDestination = this.getDestination().equals(arc.getDestination());
                } else {
                    sameDestination = (getDestination() == null && arc.getDestination() == null);
                }
                boolean samePicker = false;
                if (getPicker() != null && arc.getDestination() != null) {
                    samePicker = this.getPicker().equals(arc.getPicker());
                } else {
                    samePicker = (getPicker() == null && arc.getPicker() == null);
                }
                return (sameOrigin && sameDestination && samePicker);
            }
            return false;
        }

        /**
         * Ensuring that two PickableArcs have the same hashcodes.
         */
        @Override
        public int hashCode() {
            return getOrigin().hashCode();
        }

        /**
         * Tests whether this arc as an ancestor that equals itself. Allows the detection of cycles in a graph (Cycling <> redundant arcs)
         */
        public boolean provokesCycling() {
            IArc currentAncestor = this.getParentArc();
            while (currentAncestor instanceof IPickableArc) {
                if (currentAncestor.equals(this)) {
                    return true;
                } else {
                    currentAncestor = ((IPickableArc) currentAncestor).getParentArc();
                }
            }
            return false;
        }

        public List<Object> getCycle() {
            List<Object> result = Lists.newArrayList();
            result.add(this.getDestination());
            result.add(this.getOrigin());

            IArc currentAncestor = this.getParentArc();
            while (currentAncestor instanceof IPickableArc && currentAncestor != this) {
                result.add(currentAncestor.getOrigin());
                currentAncestor = ((IPickableArc) currentAncestor).getParentArc();
            }
            return result;
        }

    }

}