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/*
* Copyright (c) 2007 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* - Redistribution of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistribution in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
* INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
* MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
* ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
* ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
* DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
* DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
* ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
* SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that this software is not designed or intended for use
* in the design, construction, operation or maintenance of any nuclear
* facility.
*
*/
package net.java.joglutils.msg.actions;
import java.lang.reflect.*;
import net.java.joglutils.msg.misc.*;
import net.java.joglutils.msg.nodes.*;
/** The base class of all actions, which are applied to nodes in the
scene graph to implement operations such as rendering. <P>
Subclasses of Action should define, by convention, a method <BR>
<PRE> public static State getDefaultState()</PRE>
returning a {@link net.java.joglutils.msg.misc.State State}
object, which is used to enable the elements in the state which
should be updated by the action's traversal of nodes. Each Action
instance maintains a State object internally which is initialized
from this default. Note that different actions may enable
different elements of the global state. <P>
Subclasses of Action should also define, by convention, a method <BR>
<PRE> public static void addActionMethod(Class<? extends Node> nodeType, Method m)</PRE>
which is used to add action methods to the particular Action
class. This may be used by developers to attach new functionality
to the Action for new node types they define.
*/
public abstract class Action {
/** Applies this Action to a particular node. This is how operations
such as rendering are initiated. */
public abstract void apply(Node node);
/** Returns the global state this action encompasses, which is
altered by the nodes the action traverses. */
public abstract State getState();
/** Returns the path to the node currently being traversed. The
caller should make a copy of this path if it is desired to keep
it around. */
public Path getPath() {
return path;
}
private Object[] argTmp = new Object[2];
/** Invokes the appropriate action method for the given Node. */
protected void apply(ActionTable table, Node node) {
try {
Method m = table.lookupActionMethod(node);
if (m != null) {
argTmp[0] = this;
argTmp[1] = node;
push(node);
try {
m.invoke(null, argTmp);
} finally {
pop();
}
}
} catch (Exception e) {
throw new RuntimeException(e);
}
}
private Path path = new Path();
/** Pushes the given Node onto the internal Path this Action
maintains during traversal. */
private void push(Node node) {
path.add(node);
}
/** Pops the given Node off the internal Path this Action maintains
during traversal. */
private void pop() {
path.remove(path.size() - 1);
}
}
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