-// $Id: CQLParser.java,v 1.3 2002-10-24 16:06:34 mike Exp $
+// $Id: CQLParser.java,v 1.4 2002-10-25 07:38:16 mike Exp $
package org.z3950.zing.cql;
import java.util.Properties;
* Compiles a CQL string into a parse tree ...
* ###
*
- * @version $Id: CQLParser.java,v 1.3 2002-10-24 16:06:34 mike Exp $
+ * @version $Id: CQLParser.java,v 1.4 2002-10-25 07:38:16 mike Exp $
* @see <A href="http://zing.z3950.org/cql/index.html"
* >http://zing.z3950.org/cql/index.html</A>
*/
-class CQLCompiler {
+class CQLParser {
private String cql;
- private String qualset;
- private Properties qualsetProperties;
private StreamTokenizer st;
private class CQLParseException extends Exception {
CQLParseException(String s) { super(s); }
}
- public CQLCompiler(String cql, String qualset) {
- this.cql = cql;
- this.qualset = qualset;
+ public CQLParser() {
+ // Nothing to do: do we need this constructor, then?
}
- public String convertToPQN()
+ public CQLNode parse(String cql)
throws FileNotFoundException, IOException {
-
- if (qualsetProperties == null) {
- // ### Could think about caching named qualifier sets
- // across compilations (i.e. shared, in a static
- // Hashtable, between multiple CQLCompiler
- // instances.) Probably not worth it.
- InputStream is = this.getClass().getResourceAsStream(qualset);
- if (is == null)
- throw new FileNotFoundException("getResourceAsStream(" +
- qualset + ")");
- qualsetProperties = new Properties();
- qualsetProperties.load(is);
- }
-
+ this.cql = cql;
st = new StreamTokenizer(new StringReader(cql));
+ // ### these settings are wrong
st.wordChars('/', '/');
st.wordChars('0', '9'); // ### but 1 is still recognised as TT_NUM
st.wordChars('.', '.');
// }
st.nextToken();
- String ret;
+ CQLNode root;
try {
- ret = parse_expression();
+ root = parse_expression();
} catch (CQLParseException ex) {
System.err.println("### Oops: " + ex);
return null;
return null;
}
- // Interpret attributes as BIB-1 unless otherwise specified
- return "@attrset bib-1 " + ret;
+ return root;
}
- private String parse_expression()
+ private CQLNode parse_expression()
throws CQLParseException, IOException {
- String term = parse_term();
+ CQLNode term = parse_term();
while (st.ttype == st.TT_WORD) {
String op = st.sval.toLowerCase();
- if (!st.sval.equals("and") &&
- !st.sval.equals("or") &&
- !st.sval.equals("not"))
- break;
- match(st.TT_WORD);
- String term2 = parse_term();
- term = "@" + op + " " + term + " " + term2;
+ if (st.sval.equals("and")) {
+ match(st.TT_WORD);
+ CQLNode term2 = parse_term();
+ term = new CQLAndNode(term, term2);
+ } else if (st.sval.equals("or")) {
+ match(st.TT_WORD);
+ CQLNode term2 = parse_term();
+ term = new CQLOrNode(term, term2);
+ } else if (st.sval.equals("not")) {
+ match(st.TT_WORD);
+ CQLNode term2 = parse_term();
+ term = new CQLNotNode(term, term2);
+ }
}
return term;
}
- private String parse_term()
+ private CQLNode parse_term()
throws CQLParseException, IOException {
if (st.ttype == '(') {
match('(');
- String expr = parse_expression();
+ CQLNode expr = parse_expression();
match(')');
return expr;
}
- String word = null;
- String attrs = "";
-
- // ### We treat ',' and '=' equivalently here, which isn't quite right.
- while (st.ttype == st.TT_WORD) {
- word = st.sval;
- match(st.TT_WORD);
- if (st.ttype != '=' && st.ttype != ',') {
- // end of qualifer list
- break;
- }
-
- String attr = qualsetProperties.getProperty(word);
- if (attr == null) {
- throw new CQLParseException("unrecognised qualifier: " + word);
- }
- attrs = attrs + attr + " ";
- match(st.ttype);
- word = null; // mark as not-yet-read
- }
-
- if (word == null) {
- // got to the end of a "foo,bar=" sequence
- word = st.sval;
- if (st.ttype != '\'' || st.ttype != '"') {
- word = "\"" + word + "\"";
- match(st.ttype);
- } else {
- match(st.TT_WORD);
- }
- }
-
- return attrs + word;
+ String word = st.sval;
+ return new CQLTermNode("x", "=", word);
}
private void match(int token)
private static String render(StreamTokenizer st, int token, String str) {
String ret;
- switch (token) {
- case st.TT_EOF: return "EOF";
- case st.TT_EOL: return "EOL";
- case st.TT_NUMBER: return "number";
- case st.TT_WORD: ret = "word"; break;
- case '"': case '\'': ret = "string"; break;
- default: return "'" + String.valueOf((char) token) + "'";
+ if (token == st.TT_EOF) {
+ return "EOF";
+ } else if (token == st.TT_EOL) {
+ return "EOL";
+ } else if (token == st.TT_NUMBER) {
+ return "number";
+ } else if (token == st.TT_WORD) {
+ return "word";
+ } else if (token == '"' && token == '\'') {
+ return "string";
}
- if (str != null)
- ret += "(\"" + str + "\")";
- return ret;
+ return "'" + String.valueOf((char) token) + "'";
}
- // ### Not really the right place for this test harness.
+
+ // Test harness.
//
- // e.g. java uk.org.miketaylor.zoom.CQLCompiler
- // '(au=Kerninghan or au=Ritchie) and ti=Unix' qualset.properties
+ // e.g. echo '(au=Kerninghan or au=Ritchie) and ti=Unix' |
+ // java org.z3950.zing.cql.CQLParser
// yields:
- // @and
- // @or
- // @attr 1=1 @attr 4=1 Kerninghan
- // @attr 1=1 @attr 4=1 Ritchie
- // @attr 1=4 @attr 4=1 Unix
+ // ###
//
public static void main (String[] args) {
- if (args.length != 2) {
- System.err.println("Usage: CQLQuery <cql> <qualset>");
+ if (args.length != 0) {
+ System.err.println("Usage: " + args[0]);
System.exit(1);
}
- CQLCompiler cc = new CQLCompiler(args[0], args[1]);
+ byte[] bytes = new byte[1000];
try {
- String pqn = cc.convertToPQN();
- System.out.println(pqn);
- } catch (FileNotFoundException ex) {
- System.err.println("Can't find qualifier set: " + ex);
- System.exit(2);
- } catch (IOException ex) {
- System.err.println("Can't read qualifier set: " + ex);
+ int nbytes = System.in.read(bytes);
+ } catch (java.io.IOException ex) {
+ System.err.println("Can't read query: " + ex);
System.exit(2);
}
+ String cql = String(bytes);
+ CQLParser parser = new CQLParser();
+ CQLNode root = parser.parse(cql);
+ System.out.println(root.toXCQL());
}
}
projects / cql-java-moved-to-github.git / blobdiff