001package de.deepamehta.core.impl;
002
003import de.deepamehta.core.Association;
004import de.deepamehta.core.DeepaMehtaObject;
005import de.deepamehta.core.Topic;
006import de.deepamehta.core.model.AssociationModel;
007import de.deepamehta.core.model.DeepaMehtaObjectModel;
008import de.deepamehta.core.model.TopicModel;
009
010import java.util.Iterator;
011
012
013
014/**
015 * An iterable over all topics stored in the DB.
016 */
017class TopicIterable implements Iterable<Topic> {
018
019    private Iterator<Topic> topics;
020
021    TopicIterable(PersistenceLayer pl) {
022        this.topics = new TopicIterator(pl);
023    }
024
025    @Override
026    public Iterator<Topic> iterator() {
027        return topics;
028    }
029}
030
031/**
032 * An iterable over all associations stored in the DB.
033 */
034class AssociationIterable implements Iterable<Association> {
035
036    private Iterator<Association> assocs;
037
038    AssociationIterable(PersistenceLayer pl) {
039        this.assocs = new AssociationIterator(pl);
040    }
041
042    @Override
043    public Iterator<Association> iterator() {
044        return assocs;
045    }
046}
047
048
049
050// ===
051
052
053
054class TopicIterator extends ObjectIterator<Topic, TopicModelImpl> {
055
056    TopicIterator(PersistenceLayer pl) {
057        super(pl);
058    }
059
060    @Override
061    Iterator<TopicModelImpl> fetchObjects() {
062        return pl.fetchAllTopics();
063    }
064
065    @Override
066    Topic instantiateObject(TopicModelImpl model) {
067        return pl.checkReadAccessAndInstantiate(model);
068    }
069}
070
071
072
073class AssociationIterator extends ObjectIterator<Association, AssociationModelImpl> {
074
075    AssociationIterator(PersistenceLayer pl) {
076        super(pl);
077    }
078
079    @Override
080    Iterator<AssociationModelImpl> fetchObjects() {
081        return pl.fetchAllAssociations();
082    }
083
084    @Override
085    Association instantiateObject(AssociationModelImpl model) {
086        return pl.checkReadAccessAndInstantiate(model);
087    }
088}
089
090
091
092abstract class ObjectIterator<O extends DeepaMehtaObject, M extends DeepaMehtaObjectModelImpl> implements Iterator<O> {
093
094    // ---------------------------------------------------------------------------------------------- Instance Variables
095
096    protected PersistenceLayer pl;
097    private Iterator<M> objects;
098
099    // ---------------------------------------------------------------------------------------------------- Constructors
100
101    ObjectIterator(PersistenceLayer pl) {
102        this.pl = pl;
103        this.objects = fetchObjects();
104    }
105
106    // -------------------------------------------------------------------------------------------------- Public Methods
107
108    @Override
109    public boolean hasNext() {
110        return objects.hasNext();
111    }
112
113    @Override
114    public O next() {
115        return instantiateObject(objects.next());
116    }
117
118    @Override
119    public void remove() {
120        objects.remove();
121    }
122
123    // ----------------------------------------------------------------------------------------- Package Private Methods
124
125    abstract Iterator<M> fetchObjects();
126
127    abstract O instantiateObject(M model);
128}