source: josm/trunk/src/org/openstreetmap/josm/data/osm/BackreferencedDataSet.java@ 2555

// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.data.osm;

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

public class BackreferencedDataSet {
    public static class RelationToChildReference {
        private Relation parent;
        private int position;
        private String role;
        private OsmPrimitive child;

        public RelationToChildReference(Relation parent, int position, String role, OsmPrimitive child) {
            this.parent = parent;
            this.position = position;
            this.role = role;
            this.child = child;
        }

        public RelationToChildReference(Relation parent, int position, RelationMember member) {
            this.parent = parent;
            this.position = position;
            this.role = member.getRole();
            this.child = member.getMember();
        }

        public Relation getParent() {
            return parent;
        }

        public int getPosition() {
            return position;
        }

        public String getRole() {
            return role;
        }

        public OsmPrimitive getChild() {
            return child;
        }

        @Override
        public int hashCode() {
            final int prime = 31;
            int result = 1;
            result = prime * result + ((child == null) ? 0 : child.hashCode());
            result = prime * result + ((parent == null) ? 0 : parent.hashCode());
            result = prime * result + position;
            result = prime * result + ((role == null) ? 0 : role.hashCode());
            return result;
        }
        @Override
        public boolean equals(Object obj) {
            if (this == obj)
                return true;
            if (obj == null)
                return false;
            if (getClass() != obj.getClass())
                return false;
            RelationToChildReference other = (RelationToChildReference) obj;
            if (child == null) {
                if (other.child != null)
                    return false;
            } else if (!child.equals(other.child))
                return false;
            if (parent == null) {
                if (other.parent != null)
                    return false;
            } else if (!parent.equals(other.parent))
                return false;
            if (position != other.position)
                return false;
            if (role == null) {
                if (other.role != null)
                    return false;
            } else if (!role.equals(other.role))
                return false;
            return true;
        }
    }

    /**
     * Replies the set of parent primitives for a given child primitive. Replies
     * an empty set if no parents refer to the child.
     *
     * @param child the child primitive
     * @return  the set of parent primitives for a given child primitive.
     */
    public Set<OsmPrimitive> getParents(OsmPrimitive child) {
        return new HashSet<OsmPrimitive>(child.getReferrers());
    }

    public Set<OsmPrimitive> getParents(Collection<? extends OsmPrimitive> children) {
        if (children == null) return Collections.emptySet();
        children.remove(null);

        Set<OsmPrimitive> parents = new HashSet<OsmPrimitive>();
        for(OsmPrimitive child: children) {
            parents.addAll(child.getReferrers());
        }
        return parents;
    }

    /**
     * Replies true if there is at least one parent referring to child;
     * false otherwise
     *
     * @param child the child primitive
     * @return true if there is at least one parent referring to child;
     */
    public boolean hasParents(OsmPrimitive child) {
        return ! getParents(child).isEmpty();
    }

    /**
     * Replies a set of all {@see RelationToChildReference}s for a given child primitive.
     *
     * @param child the child primitive
     * @return  a set of all {@see RelationToChildReference}s for a given child primitive
     */
    public Set<RelationToChildReference> getRelationToChildReferences(OsmPrimitive child) {
        Set<Relation> parents = OsmPrimitive.getFilteredSet(getParents(child), Relation.class);
        Set<RelationToChildReference> references = new HashSet<RelationToChildReference>();
        for (Relation parent: parents) {
            for (int i=0; i < parent.getMembersCount(); i++) {
                if (parent.getMember(i).refersTo(child)) {
                    references.add(new RelationToChildReference(parent, i, parent.getMember(i)));
                }
            }
        }
        return references;
    }

    /**
     * Replies a set of all {@see RelationToChildReference}s for a collection of child primitives
     *
     * @param children the collection of child primitives
     * @return  a set of all {@see RelationToChildReference}s to the children in the collection of child
     * primitives
     */
    public Set<RelationToChildReference> getRelationToChildReferences(Collection<? extends OsmPrimitive> children) {
        Set<RelationToChildReference> references = new HashSet<RelationToChildReference>();
        for (OsmPrimitive child: children) {
            references.addAll(getRelationToChildReferences(child));
        }
        return references;
    }
}