-// $Id: CQLNode.java,v 1.11 2002-11-06 00:05:58 mike Exp $
+// $Id: CQLNode.java,v 1.12 2002-11-06 20:13:45 mike Exp $
package org.z3950.zing.cql;
import java.util.Properties;
/**
* Represents a node in a CQL parse-tree.
*
- * @version $Id: CQLNode.java,v 1.11 2002-11-06 00:05:58 mike Exp $
+ * @version $Id: CQLNode.java,v 1.12 2002-11-06 20:13:45 mike Exp $
*/
public abstract class CQLNode {
CQLNode() {} // prevent javadoc from documenting this
/**
* Renders a parse-tree into a Yaz-style PQF string.
* <P>
+ * <PRE>
+ query ::= top-set query-struct.
+ top-set ::= [ '@attrset' string ]
+ query-struct ::= attr-spec | simple | complex | '@term' term-type
+ attr-spec ::= '@attr' [ string ] string query-struct
+ complex ::= operator query-struct query-struct.
+ operator ::= '@and' | '@or' | '@not' | '@prox' proximity.
+ simple ::= result-set | term.
+ result-set ::= '@set' string.
+ term ::= string.
+ proximity ::= exclusion distance ordered relation which-code unit-code.
+ exclusion ::= '1' | '0' | 'void'.
+ distance ::= integer.
+ ordered ::= '1' | '0'.
+ relation ::= integer.
+ which-code ::= 'known' | 'private' | integer.
+ unit-code ::= integer.
+ term-type ::= 'general' | 'numeric' | 'string' | 'oid' | 'datetime' | 'null'.
+ * </PRE>
* @return
* A String containing a PQF query equivalent to the parse-tree
* whose root is this node. This may be fed into the tool of
* your choice to obtain a BER-encoded packet.
*/
abstract public String toPQF(Properties config)
- throws UnknownQualifierException, UnknownRelationException;
+ throws PQFTranslationException;
/**
* Returns a String of spaces for indenting to the specified level.