Class SimpleIndexer

src/main/java/pascal/taie/util/SimpleIndexer.java:42–106

A simple map and list based implementation of Indexer. The indexes of the objects are same as their indexes in the list. If #getIndex(Object) is called with an object that was absent in this indexer, it will be added to the indexer automatically. If #getObject(int) is cal

 * {@code getIndex(o)}.
 */
public class SimpleIndexer<E> implements Indexer<E> {

    private final Map<E, Integer> obj2index;

    private final List<E> index2obj;

    private int counter = 0;

    /**
     * Constructs an empty indexer.
     */
    public SimpleIndexer() {
        this.obj2index = Maps.newMap();
        this.index2obj = new ArrayList<>();
    }

    /**
     * Constructs an empty mapper with the specified initial capacity.
     */
    public SimpleIndexer(int initialCapacity) {
        this.obj2index = Maps.newMap(initialCapacity);
        this.index2obj = new ArrayList<>(initialCapacity);
    }

    /**
     * Constructs a mapper with a collection. The elements in the collection
     * will be added to the new-created mapper.
     */
    public SimpleIndexer(Collection<? extends E> c) {
        this(c.size());
        c.forEach(this::getIndex);
    }

    @Override
    public int getIndex(E o) {
        Objects.requireNonNull(o, "null cannot be indexed");
        Integer id = obj2index.get(o);
        if (id == null) {
            obj2index.put(o, counter);
            index2obj.add(o);
            return counter++;
        } else {
            return id;
        }
    }

    @Override
    public E getObject(int index) {
        try {
            return index2obj.get(index);
        } catch (IndexOutOfBoundsException e) {
            throw new IllegalArgumentException(
                    "index " + index + " was not mapped to any object", e);
        }
    }

    @Override
    public String toString() {