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/*
* Copyright © 2002 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* California 95054, U.S.A. All rights reserved. Sun Microsystems, Inc. has
* intellectual property rights relating to technology embodied in the product
* that is described in this document. In particular, and without limitation,
* these intellectual property rights may include one or more of the U.S.
* patents listed at http://www.sun.com/patents and one or more additional
* patents or pending patent applications in the U.S. and in other countries.
* U.S. Government Rights - Commercial software. Government users are subject
* to the Sun Microsystems, Inc. standard license agreement and applicable
* provisions of the FAR and its supplements. Use is subject to license terms.
* Sun, Sun Microsystems, the Sun logo and Java are trademarks or registered
* trademarks of Sun Microsystems, Inc. in the U.S. and other countries. This
* product is covered and controlled by U.S. Export Control laws and may be
* subject to the export or import laws in other countries. Nuclear, missile,
* chemical biological weapons or nuclear maritime end uses or end users,
* whether direct or indirect, are strictly prohibited. Export or reexport
* to countries subject to U.S. embargo or to entities identified on U.S.
* export exclusion lists, including, but not limited to, the denied persons
* and specially designated nationals lists is strictly prohibited.
*/
/* This is an example of how the Visitor pattern might be used to
implement the dumping code that comes with SimpleNode. It's a bit
long-winded, but it does illustrate a couple of the main points.
1) the visitor can maintain state between the nodes that it visits
(for example the current indentation level).
2) if you don't implement a jjtAccept() method for a subclass of
SimpleNode, then SimpleNode's acceptor will get called.
3) the utility method childrenAccept() can be useful when
implementing preorder or postorder tree walks.
*/
public class eg4DumpVisitor implements eg4Visitor
{
private int indent = 0;
private String indentString() {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < indent; ++i) {
sb.append(" ");
}
return sb.toString();
}
public Object visit(SimpleNode node, Object data) {
System.out.println(indentString() + node +
": acceptor not unimplemented in subclass?");
++indent;
data = node.childrenAccept(this, data);
--indent;
return data;
}
public Object visit(ASTStart node, Object data) {
System.out.println(indentString() + node);
++indent;
data = node.childrenAccept(this, data);
--indent;
return data;
}
public Object visit(ASTAdd node, Object data) {
System.out.println(indentString() + node);
++indent;
data = node.childrenAccept(this, data);
--indent;
return data;
}
public Object visit(ASTMult node, Object data) {
System.out.println(indentString() + node);
++indent;
data = node.childrenAccept(this, data);
--indent;
return data;
}
public Object visit(ASTMyOtherID node, Object data) {
System.out.println(indentString() + node);
++indent;
data = node.childrenAccept(this, data);
--indent;
return data;
}
public Object visit(ASTInteger node, Object data) {
System.out.println(indentString() + node);
++indent;
data = node.childrenAccept(this, data);
--indent;
return data;
}
}
/*end*/
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