Hello all.
I am developing a calculation framework for my firm using ANTLR3 and Java.
I want to serialize an AST for reusing it a lot of times, so this way I can
save parsing time for each calculation.
I have developed a CommonTree derived class ICalcTree that implements
Serialize, and another class ICalcTreeAdaptor derived from
CommonTreeAdaptor.
In parser options, I have:
output = AST;
ASTLabelType = ICalcTree;
language = Java;
The program uses the parser this way:
String formula = "a=1+2";
Reader reader = new CharArrayReader(formula.toCharArray());
ICalcLexer lexer = new ICalcLexer(new ANTLRReaderStream(reader));
CommonTokenStream cts = new CommonTokenStream(lexer);
ICalcParser tokenParser = new ICalcParser(cts);
TreeAdaptor adaptor = new ICalcTreeAdaptor();
tokenParser.setTreeAdaptor(adaptor);
ICalcParser.formula_return parserResult =
tokenParser.formula(); // start rule method
reader.close();
ICalcTree ast = (ICalcTree) parserResult.getTree();
// Serialize
ByteArrayOutputStream bs = new ByteArrayOutputStream();
ObjectOutputStream os = new ObjectOutputStream(bs);
os.writeObject(ast);
os.close();
byte[] buf = bs.toByteArray();
String serialized = StringUtils.byteArrayToHexString(buf);
// Unserialize
byte[] buf_unserialized =
StringUtils.hexStringToByteArray(serialized);
ByteArrayInputStream bi = new ByteArrayInputStream(buf_unserialized);
ObjectInputStream ois = new ObjectInputStream(bi);
try {
ICalcTree new_ast = new ICalcTree();
new_ast = (ICalcTree) ois.readObject();
System.out.println(new_ast.toStringTree());
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
It always print nil, for whatever formula string.
What am I doing wrong? How can I serialize the AST so it can be reused many
times?
Thank you for your assistance.
David Marín Carreño
S.I.C.E.
Dirección Técnica.
Tfno 91 623 22 30
E-mail: [email protected]
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