-// ### not _quite_ finished yet ...
+// $Id: CQLParser.java,v 1.20 2002-11-14 22:04:16 mike Exp $
+
+package org.z3950.zing.cql;
+import java.io.IOException;
+import java.util.Vector;
+import java.util.Properties;
+import java.io.InputStream;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+
+
+/**
+ * Compiles CQL strings into parse trees of CQLNode subtypes.
+ *
+ * @version $Id: CQLParser.java,v 1.20 2002-11-14 22:04:16 mike Exp $
+ * @see <A href="http://zing.z3950.org/cql/index.html"
+ * >http://zing.z3950.org/cql/index.html</A>
+ */
+public class CQLParser {
+ private CQLLexer lexer;
+ static private boolean DEBUG = false;
+ static private boolean LEXDEBUG = false;
+
+ private static void debug(String str) {
+ if (DEBUG)
+ System.err.println("PARSEDEBUG: " + str);
+ }
+
+ /**
+ * Compiles a CQL query.
+ * <P>
+ * The resulting parse tree may be further processed by hand (see
+ * the individual node-types' documentation for details on the
+ * data structure) or, more often, simply rendered out in the
+ * desired form using one of the back-ends. <TT>toCQL()</TT>
+ * returns a decompiled CQL query equivalent to the one that was
+ * compiled in the first place; and <TT>toXCQL()</TT> returns an
+ * XML snippet representing the query.
+ *
+ * @param cql The query
+ * @return A CQLNode object which is the root of a parse
+ * tree representing the query. */
+ public CQLNode parse(String cql)
+ throws CQLParseException, IOException {
+ lexer = new CQLLexer(cql, LEXDEBUG);
+
+ lexer.nextToken();
+ debug("about to parseQuery()");
+ CQLNode root = parseQuery("srw.serverChoice", new CQLRelation("scr"));
+ if (lexer.ttype != lexer.TT_EOF)
+ throw new CQLParseException("junk after end: " + lexer.render());
+
+ return root;
+ }
+
+ private CQLNode parseQuery(String qualifier, CQLRelation relation)
+ throws CQLParseException, IOException {
+ debug("in parseQuery()");
+
+ CQLNode term = parseTerm(qualifier, relation);
+ while (lexer.ttype != lexer.TT_EOF &&
+ lexer.ttype != ')') {
+ if (lexer.ttype == lexer.TT_AND) {
+ match(lexer.TT_AND);
+ CQLNode term2 = parseTerm(qualifier, relation);
+ term = new CQLAndNode(term, term2);
+ } else if (lexer.ttype == lexer.TT_OR) {
+ match(lexer.TT_OR);
+ CQLNode term2 = parseTerm(qualifier, relation);
+ term = new CQLOrNode(term, term2);
+ } else if (lexer.ttype == lexer.TT_NOT) {
+ match(lexer.TT_NOT);
+ CQLNode term2 = parseTerm(qualifier, relation);
+ term = new CQLNotNode(term, term2);
+ } else if (lexer.ttype == lexer.TT_PROX) {
+ match(lexer.TT_PROX);
+ CQLProxNode proxnode = new CQLProxNode(term);
+ gatherProxParameters(proxnode);
+ CQLNode term2 = parseTerm(qualifier, relation);
+ proxnode.addSecondSubterm(term2);
+ term = (CQLNode) proxnode;
+ } else {
+ throw new CQLParseException("expected boolean, got " +
+ lexer.render());
+ }
+ }
+
+ debug("no more ops");
+ return term;
+ }
+
+ private CQLNode parseTerm(String qualifier, CQLRelation relation)
+ throws CQLParseException, IOException {
+ debug("in parseTerm()");
+
+ String word;
+ while (true) {
+ if (lexer.ttype == '(') {
+ debug("parenthesised term");
+ match('(');
+ CQLNode expr = parseQuery(qualifier, relation);
+ match(')');
+ return expr;
+ } else if (lexer.ttype == '>') {
+ match('>');
+ return parsePrefix(qualifier, relation);
+ }
+
+ debug("non-parenthesised term");
+ word = matchSymbol("qualifier or term");
+ if (!isBaseRelation())
+ break;
+
+ qualifier = word;
+ relation = new CQLRelation(lexer.render(lexer.ttype, false));
+ match(lexer.ttype);
+
+ while (lexer.ttype == '/') {
+ match('/');
+ if (lexer.ttype != lexer.TT_RELEVANT &&
+ lexer.ttype != lexer.TT_FUZZY &&
+ lexer.ttype != lexer.TT_STEM)
+ throw new CQLParseException("expected relation modifier, "
+ + "got " + lexer.render());
+ relation.addModifier(lexer.sval.toLowerCase());
+ match(lexer.ttype);
+ }
+
+ debug("qualifier='" + qualifier + ", " +
+ "relation='" + relation.toCQL() + "'");
+ }
+
+ CQLTermNode node = new CQLTermNode(qualifier, relation, word);
+ debug("made term node " + node.toCQL());
+ return node;
+ }
+
+ private CQLNode parsePrefix(String qualifier, CQLRelation relation)
+ throws CQLParseException, IOException {
+ debug("prefix mapping");
+
+ String name = null;
+ String identifier = matchSymbol("prefix-name");
+ if (lexer.ttype == '=') {
+ match('=');
+ name = identifier;
+ identifier = matchSymbol("prefix-identifer");
+ }
+ CQLNode term = parseTerm(qualifier, relation);
+ return new CQLPrefixNode(name, identifier, term);
+ }
+
+ private void gatherProxParameters(CQLProxNode node)
+ throws CQLParseException, IOException {
+ for (int i = 0; i < 4; i++) {
+ if (lexer.ttype != '/')
+ return; // end of proximity parameters
+
+ match('/');
+ if (lexer.ttype != '/') {
+ // not an omitted default
+ switch (i) {
+ // Order should be: relation/distance/unit/ordering
+ // For now, use MA's: unit/relation/distance/ordering
+ case 0: gatherProxRelation(node); break;
+ case 1: gatherProxDistance(node); break;
+ case 2: gatherProxUnit(node); break;
+ case 3: gatherProxOrdering(node); break;
+ }
+ }
+ }
+ }
+
+ private void gatherProxRelation(CQLProxNode node)
+ throws CQLParseException, IOException {
+ if (!isProxRelation())
+ throw new CQLParseException("expected proximity relation, got " +
+ lexer.render());
+ node.addModifier("relation", lexer.render(lexer.ttype, false));
+ match(lexer.ttype);
+ debug("gPR matched " + lexer.render(lexer.ttype, false));
+ }
+
+ private void gatherProxDistance(CQLProxNode node)
+ throws CQLParseException, IOException {
+ if (lexer.ttype != lexer.TT_NUMBER)
+ throw new CQLParseException("expected proximity distance, got " +
+ lexer.render());
+ node.addModifier("distance", lexer.render(lexer.ttype, false));
+ match(lexer.ttype);
+ debug("gPD matched " + lexer.render(lexer.ttype, false));
+ }
+
+ private void gatherProxUnit(CQLProxNode node)
+ throws CQLParseException, IOException {
+ if (lexer.ttype != lexer.TT_pWORD &&
+ lexer.ttype != lexer.TT_SENTENCE &&
+ lexer.ttype != lexer.TT_PARAGRAPH &&
+ lexer.ttype != lexer.TT_ELEMENT)
+ throw new CQLParseException("expected proximity unit, got " +
+ lexer.render());
+ node.addModifier("unit", lexer.render());
+ match(lexer.ttype);
+ }
+
+ private void gatherProxOrdering(CQLProxNode node)
+ throws CQLParseException, IOException {
+ if (lexer.ttype != lexer.TT_ORDERED &&
+ lexer.ttype != lexer.TT_UNORDERED)
+ throw new CQLParseException("expected proximity ordering, got " +
+ lexer.render());
+ node.addModifier("ordering", lexer.render());
+ match(lexer.ttype);
+ }
+
+ private boolean isBaseRelation() {
+ debug("isBaseRelation: checking ttype=" + lexer.ttype +
+ " (" + lexer.render() + ")");
+ return (isProxRelation() ||
+ lexer.ttype == lexer.TT_ANY ||
+ lexer.ttype == lexer.TT_ALL ||
+ lexer.ttype == lexer.TT_EXACT ||
+ lexer.ttype == lexer.TT_SCR);
+ }
+
+ private boolean isProxRelation() {
+ debug("isProxRelation: checking ttype=" + lexer.ttype +
+ " (" + lexer.render() + ")");
+ return (lexer.ttype == '<' ||
+ lexer.ttype == '>' ||
+ lexer.ttype == '=' ||
+ lexer.ttype == lexer.TT_LE ||
+ lexer.ttype == lexer.TT_GE ||
+ lexer.ttype == lexer.TT_NE);
+ }
+
+ private void match(int token)
+ throws CQLParseException, IOException {
+ debug("in match(" + lexer.render(token, true) + ")");
+ if (lexer.ttype != token)
+ throw new CQLParseException("expected " +
+ lexer.render(token, true) +
+ ", " + "got " + lexer.render());
+ int tmp = lexer.nextToken();
+ debug("match() got token=" + lexer.ttype + ", " +
+ "nval=" + lexer.nval + ", sval='" + lexer.sval + "'" +
+ " (tmp=" + tmp + ")");
+ }
+
+ private String matchSymbol(String expected)
+ throws CQLParseException, IOException {
+
+ debug("in matchSymbol()");
+ if (lexer.ttype == lexer.TT_WORD ||
+ lexer.ttype == lexer.TT_NUMBER ||
+ lexer.ttype == '"' ||
+ // The following is a complete list of keywords. Because
+ // they're listed here, they can be used unquoted as
+ // qualifiers, terms, prefix names and prefix identifiers.
+ lexer.ttype == lexer.TT_AND ||
+ lexer.ttype == lexer.TT_OR ||
+ lexer.ttype == lexer.TT_NOT ||
+ lexer.ttype == lexer.TT_PROX ||
+ lexer.ttype == lexer.TT_ANY ||
+ lexer.ttype == lexer.TT_ALL ||
+ lexer.ttype == lexer.TT_EXACT ||
+ lexer.ttype == lexer.TT_pWORD ||
+ lexer.ttype == lexer.TT_SENTENCE ||
+ lexer.ttype == lexer.TT_PARAGRAPH ||
+ lexer.ttype == lexer.TT_ELEMENT ||
+ lexer.ttype == lexer.TT_ORDERED ||
+ lexer.ttype == lexer.TT_UNORDERED ||
+ lexer.ttype == lexer.TT_RELEVANT ||
+ lexer.ttype == lexer.TT_FUZZY ||
+ lexer.ttype == lexer.TT_STEM ||
+ lexer.ttype == lexer.TT_SCR) {
+ String symbol = (lexer.ttype == lexer.TT_NUMBER) ?
+ lexer.render() : lexer.sval;
+ match(lexer.ttype);
+ return symbol;
+ }
+
+ throw new CQLParseException("expected " + expected + ", " +
+ "got " + lexer.render());
+ }
+
+
+ /**
+ * Simple test-harness for the CQLParser class.
+ * <P>
+ * Reads a CQL query either from its command-line argument, if
+ * there is one, or standard input otherwise. So these two
+ * invocations are equivalent:
+ * <PRE>
+ * CQLParser 'au=(Kerninghan or Ritchie) and ti=Unix'
+ * echo au=(Kerninghan or Ritchie) and ti=Unix | CQLParser
+ * </PRE>
+ * The test-harness parses the supplied query and renders is as
+ * XCQL, so that both of the invocations above produce the
+ * following output:
+ * <PRE>
+ * <triple>
+ * <boolean>
+ * <value>and</value>
+ * </boolean>
+ * <triple>
+ * <boolean>
+ * <value>or</value>
+ * </boolean>
+ * <searchClause>
+ * <index>au</index>
+ * <relation>
+ * <value>=</value>
+ * </relation>
+ * <term>Kerninghan</term>
+ * </searchClause>
+ * <searchClause>
+ * <index>au</index>
+ * <relation>
+ * <value>=</value>
+ * </relation>
+ * <term>Ritchie</term>
+ * </searchClause>
+ * </triple>
+ * <searchClause>
+ * <index>ti</index>
+ * <relation>
+ * <value>=</value>
+ * </relation>
+ * <term>Unix</term>
+ * </searchClause>
+ * </triple>
+ * </PRE>
+ * <P>
+ * @param -c
+ * Causes the output to be written in CQL rather than XCQL - that
+ * is, a query equivalent to that which was input, is output. In
+ * effect, the test harness acts as a query canonicaliser.
+ * @return
+ * The input query, either as XCQL [default] or CQL [if the
+ * <TT>-c</TT> option is supplied].
+ */
+ public static void main (String[] args) {
+ char mode = 'x'; // x=XCQL, c=CQL, p=PQF
+ String pfile = null;
+
+ Vector argv = new Vector();
+ for (int i = 0; i < args.length; i++) {
+ argv.add(args[i]);
+ }
+
+ if (argv.size() > 0 && argv.get(0).equals("-c")) {
+ mode = 'c';
+ argv.remove(0);
+ } else if (argv.size() > 1 && argv.get(0).equals("-p")) {
+ mode = 'p';
+ argv.remove(0);
+ pfile = (String) argv.get(0);
+ argv.remove(0);
+ }
+
+ if (argv.size() > 1) {
+ System.err.println(
+ "Usage: CQLParser [-c] [-p <pqf-properties> [<CQL-query>]");
+ System.err.println("If unspecified, query is read from stdin");
+ System.exit(1);
+ }
+
+ String cql;
+ if (argv.size() == 1) {
+ cql = (String) argv.get(0);
+ } else {
+ byte[] bytes = new byte[10000];
+ try {
+ // Read in the whole of standard input in one go
+ int nbytes = System.in.read(bytes);
+ } catch (IOException ex) {
+ System.err.println("Can't read query: " + ex.getMessage());
+ System.exit(2);
+ }
+ cql = new String(bytes);
+ }
+
+ CQLParser parser = new CQLParser();
+ CQLNode root = null;
+ try {
+ root = parser.parse(cql);
+ } catch (CQLParseException ex) {
+ System.err.println("Syntax error: " + ex.getMessage());
+ System.exit(3);
+ } catch (IOException ex) {
+ System.err.println("Can't compile query: " + ex.getMessage());
+ System.exit(4);
+ }
+
+ try {
+ if (mode == 'c') {
+ System.out.println(root.toCQL());
+ } else if (mode == 'p') {
+ InputStream f = new FileInputStream(pfile);
+ if (f == null)
+ throw new FileNotFoundException(pfile);
+
+ Properties config = new Properties();
+ config.load(f);
+ f.close();
+ System.out.println(root.toPQF(config));
+ } else {
+ System.out.print(root.toXCQL(0));
+ }
+ } catch (IOException ex) {
+ System.err.println("Can't render query: " + ex.getMessage());
+ System.exit(5);
+ } catch (UnknownQualifierException ex) {
+ System.err.println("Unknown qualifier: " + ex.getMessage());
+ System.exit(6);
+ } catch (UnknownRelationException ex) {
+ System.err.println("Unknown relation: " + ex.getMessage());
+ System.exit(7);
+ } catch (UnknownRelationModifierException ex) {
+ System.err.println("Unknown relation modifier: " +
+ ex.getMessage());
+ System.exit(8);
+ } catch (UnknownPositionException ex) {
+ System.err.println("Unknown position: " + ex.getMessage());
+ System.exit(9);
+ } catch (PQFTranslationException ex) {
+ // We catch all of this class's subclasses, so --
+ throw new Error("can't get a PQFTranslationException");
+ }
+ }
+}