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/* Copyright (c) 2006, 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:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions 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 the Sun Microsystems, Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* 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.
* <ol>
* <li> the visitor can maintain state between the nodes that it visits
* (for example the current indentation level).
* </li>
*
* <li>if you don't implement a jjtAccept() method for a subclass of
* SimpleNode, then SimpleNode's acceptor will get called.
* </li>
* <li> the utility method childrenAccept() can be useful when
* implementing preorder or postorder tree walks.
* </li>
* </ol>
*
*/
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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