Bug 315281 update copyrights for 3.6
bundles/org.eclipse.core.databinding.observable/src/org/eclipse/core/databinding/observable/map/ComputedObservableMap.java
unhookListener(keys[i]);
			}
			knownKeys.clear();
			knownKeys = null;
		}
	}
	protected final void fireSingleChange(Object key, Object oldValue,
			Object newValue) {
		fireMapChange(Diffs.createMapDiffSingleChange(key, oldValue, newValue));
	}
	/**
	 * @since 1.2
	 */
	public Object getKeyType() {
		return keySet.getElementType();
	}
	/**
	 * @since 1.2
	 */
	public Object getValueType() {
		return valueType;
	}
	/**
	 * @since 1.3
	 */
	public Object remove(Object key) {
		checkRealm();
		Object oldValue = get(key);
		keySet().remove(key);
		return oldValue;