AbstractSet抽象类源码解析

package java.util;

public abstract class AbstractSet<E> extends AbstractCollection<E> implements Set<E> {

protected AbstractSet() {
}

public boolean equals(Object o) {
if (o == this)
return true;

if (!(o instanceof Set))
return false;
Collection c = (Collection) o;
if (c.size() != size())
return false;
try {
return containsAll(c);
} catch (ClassCastException unused)   {
return false;
} catch (NullPointerException unused) {
return false;
}
}

public int hashCode() {
int h = 0;
Iterator<E> i = iterator();
while (i.hasNext()) {
E obj = i.next();
if (obj != null)
h += obj.hashCode();
}
return h;
}

public boolean removeAll(Collection<?> c) {
boolean modified = false;

if (size() > c.size()) {
for (Iterator<?> i = c.iterator(); i.hasNext(); )
modified |= remove(i.next());
} else {
for (Iterator<?> i = iterator(); i.hasNext(); ) {
if (c.contains(i.next())) {
i.remove();
modified = true;
}
}
}
return modified;
}

}