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Java/ZZCommand.java

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+/*   
+ZZCommand.java
+ *    
+ *    Copyright (c) 1999, Ted Nelson and Tuomas Lukka
+ *
+ *    You may use and distribute under the terms of either the GNU Lesser
+ *    General Public License, either version 2 of the license or,
+ *    at your choice, any later version. Alternatively, you may use and
+ *    distribute under the terms of the XPL.
+ *
+ *    See the LICENSE.lgpl and LICENSE.xpl files for the specific terms of 
+ *    the licenses.
+ *
+ *    This software is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the README
+ *    file for more details.
+ *
+ */
+/*
+ * Written by Benjamin Fallenstein
+ */
+
+package org.gzigzag;
+import java.awt.*;
+
+/** An abstract class representing a command stored in zz space.
+ * This should be thought of as a possible successor for ZZExec. Other than
+ * ZZExec, the object created is not a scripting engine, but rather a
+ * command which can be executed with a scripting engine. Subclasses of
+ * ZZCommand are expected to implement ZOb.
+ * <p>
+ * This class also provides the static method getCommand, which returns the
+ * ZZCommand associated with a cell, if any.
+ */
+
+public abstract class ZZCommand {
+    /** Execute some code as a callback from the user interface.
+     * This is a special execution context which is triggered through user
+     * action on a user interface. Note that some of the params
+     * are redundant and only provided for ease. All the other parameters
+     * can be deduced from view, ctrlview and clicked.
+     * @param view		View where command executed
+     * @param cview		Control view of view where command executed
+     * @param key		The key the user pressed, as string, if any
+     * @param pt 		The point the user clicked on, if any
+     * @param xi	The extra object - to get what was clicked, if any
+     */
+    public void execCallback(
+		    ZZCell target,
+		    ZZView view, 
+		    ZZView cview,
+		    String key,
+		    Point pt, 
+		    ZZScene xi
+		     ) {
+	exec(target);
+    }
+
+    // /** Execute with parameters.
+    //  * XXX Needs rethinking of the arguments.
+    //  */
+    // public abstract void exec(ZZCell[] params);
+
+    /** Execute with a single parameter.
+     * An intermediate for calls which don't come from the UI, but from
+     * somewhere else (e.g., a trigger).
+     * <p>
+     * Note that UI callbacks are proxied to exec by standard (that is, if
+     * execCallback isn't overridden.)
+     */
+    public abstract void exec(ZZCell param);
+
+    public static ZZCommand getCommand(ZZCell code) {
+	// Check if it's a ZOb first:
+	if(code.s("d.clone", -1) == null &&
+	   code.s("d.1", 1) == null)
+	    return null;
+	ZOb z = ZZDefaultSpace.readZOb(code);
+	if(z != null && z instanceof ZZCommand)
+	    return (ZZCommand) z;
+	return null;
+    }
+}