// guts of Collection.java

package java.util;

public interface Collection<E> extends Iterable<E> {

    // Query Operations
    int size();
    boolean isEmpty();
    boolean contains(Object o);
    Iterator<E> iterator(); // from java.lang.Iterable<E>
    Object[] toArray();
    <T> T[] toArray(T[] a);

    // Modification Operations
    boolean add(E o);
    boolean remove(Object o);

    // Bulk Operations
    boolean containsAll(Collection<?> c);
    boolean addAll(Collection<? extends E> c);
    boolean removeAll(Collection<?> c);
    boolean retainAll(Collection<?> c);
    void clear();

    // Comparison and hashing
    boolean equals(Object o);
    int hashCode();
}