ActionMap provides mappings from
+ * Objects
+ * (called keys or Action names)
+ * to Actions.
+ * An ActionMap is usually used with an InputMap
+ * to locate a particular action
+ * when a key is pressed. As with InputMap,
+ * an ActionMap can have a parent
+ * that is searched for keys not defined in the ActionMap.
+ * As with InputMap if you create a cycle, eg:
+ *
+ * ActionMap am = new ActionMap(); + * ActionMap bm = new ActionMap(): + * am.setParent(bm); + * bm.setParent(am); + *+ * some of the methods will cause a StackOverflowError to be thrown. + * + * @see InputMap + * + * @author Scott Violet + * @since 1.3 + */ +public class ActionMap implements Serializable { + /** Handles the mapping between Action name and Action. */ + private transient ArrayTable arrayTable; + /** Parent that handles any bindings we don't contain. */ + private ActionMap parent; + + + /** + * Creates an
ActionMap with no parent and no mappings.
+ */
+ public ActionMap() {
+ }
+
+ /**
+ * Sets this ActionMap's parent.
+ *
+ * @param map the ActionMap that is the parent of this one
+ */
+ public void setParent(ActionMap map) {
+ this.parent = map;
+ }
+
+ /**
+ * Returns this ActionMap's parent.
+ *
+ * @return the ActionMap that is the parent of this one,
+ * or null if this ActionMap has no parent
+ */
+ public ActionMap getParent() {
+ return parent;
+ }
+
+ /**
+ * Adds a binding for key to action.
+ * If action is null, this removes the current binding
+ * for key.
+ * In most instances, key will be
+ * action.getValue(NAME).
+ */
+ public void put(Object key, Action action) {
+ if (key == null) {
+ return;
+ }
+ if (action == null) {
+ remove(key);
+ }
+ else {
+ if (arrayTable == null) {
+ arrayTable = new ArrayTable();
+ }
+ arrayTable.put(key, action);
+ }
+ }
+
+ /**
+ * Returns the binding for key, messaging the
+ * parent ActionMap if the binding is not locally defined.
+ */
+ public Action get(Object key) {
+ Action value = (arrayTable == null) ? null :
+ (Action)arrayTable.get(key);
+
+ if (value == null) {
+ ActionMap parent = getParent();
+
+ if (parent != null) {
+ return parent.get(key);
+ }
+ }
+ return value;
+ }
+
+ /**
+ * Removes the binding for key from this ActionMap.
+ */
+ public void remove(Object key) {
+ if (arrayTable != null) {
+ arrayTable.remove(key);
+ }
+ }
+
+ /**
+ * Removes all the mappings from this ActionMap.
+ */
+ public void clear() {
+ if (arrayTable != null) {
+ arrayTable.clear();
+ }
+ }
+
+ /**
+ * Returns the Action names that are bound in this ActionMap.
+ */
+ public Object[] keys() {
+ if (arrayTable == null) {
+ return null;
+ }
+ return arrayTable.getKeys(null);
+ }
+
+ /**
+ * Returns the number of bindings in this {@code ActionMap}.
+ *
+ * @return the number of bindings in this {@code ActionMap}
+ */
+ public int size() {
+ if (arrayTable == null) {
+ return 0;
+ }
+ return arrayTable.size();
+ }
+
+ /**
+ * Returns an array of the keys defined in this ActionMap and
+ * its parent. This method differs from keys() in that
+ * this method includes the keys defined in the parent.
+ */
+ public Object[] allKeys() {
+ int count = size();
+ ActionMap parent = getParent();
+
+ if (count == 0) {
+ if (parent != null) {
+ return parent.allKeys();
+ }
+ return keys();
+ }
+ if (parent == null) {
+ return keys();
+ }
+ Object[] keys = keys();
+ Object[] pKeys = parent.allKeys();
+
+ if (pKeys == null) {
+ return keys;
+ }
+ if (keys == null) {
+ // Should only happen if size() != keys.length, which should only
+ // happen if mutated from multiple threads (or a bogus subclass).
+ return pKeys;
+ }
+
+ HashMap keyMap = new HashMap();
+ int counter;
+
+ for (counter = keys.length - 1; counter >= 0; counter--) {
+ keyMap.put(keys[counter], keys[counter]);
+ }
+ for (counter = pKeys.length - 1; counter >= 0; counter--) {
+ keyMap.put(pKeys[counter], pKeys[counter]);
+ }
+ return keyMap.keySet().toArray();
+ }
+
+ private void writeObject(ObjectOutputStream s) throws IOException {
+ s.defaultWriteObject();
+
+ ArrayTable.writeArrayTable(s, arrayTable);
+ }
+
+ private void readObject(ObjectInputStream s) throws ClassNotFoundException,
+ IOException {
+ s.defaultReadObject();
+ for (int counter = s.readInt() - 1; counter >= 0; counter--) {
+ put(s.readObject(), (Action)s.readObject());
+ }
+ }
+}