Merge pull request #2 from zcc39r/cql-java-1

Added support for truncation attribute

etc/pqf.properties

@@ -96,6 +96,17 @@ structure.any				= 4=2
 structure.*				= 4=1
 	# phrase
 
+# Truncation attributes used to implement CQL wildcard patterns.  The
+# simpler forms, left, right- and both-truncation will be used for the
+# simplest patterns, so that we produce PQF queries that conform more
+# closely to the Bath Profile.  However, when a more complex pattern
+# such as "foo*bar" is used, we fall back on Z39.58-style masking.
+#
+truncation.right                        = 5=1
+truncation.left                         = 5=2
+truncation.both                         = 5=3
+truncation.none                         = 5=100
+
 # Finally, any additional attributes that should always be included
 # with each term can be specified in the "always" property.
 #

src/main/java/org/z3950/zing/cql/CQLTermNode.java

@@ -135,11 +135,19 @@ private List<String> getAttrs(Properties config) throws PQFTranslationException
 	}
 
 	String pos = "any";
+	String truncation = "none";
 	String text = term;
 	if (text.length() > 0 && text.substring(0, 1).equals("^")) {
 	    text = text.substring(1); // ### change not seen by caller
 	    pos = "first";
 	}
+	if (text.startsWith("*") && text.endsWith("*")) {
+	    truncation = "both";
+	} else  if (text.startsWith("*")) {
+	    truncation = "left";
+	} else if (text.endsWith("*")) {
+	    truncation = "right";
+	}
 	int len = text.length();
 	if (len > 0 && text.substring(len-1, len).equals("^")) {
 	    text = text.substring(0, len-1); // ### change not seen by caller
@@ -156,6 +164,11 @@ private List<String> getAttrs(Properties config) throws PQFTranslationException
 	    throw new UnknownPositionException(pos);
 	attrs.add(attr);
 
+	attr = config.getProperty("truncation." + truncation);
+	if (attr == null)
+	    throw new UnknownTruncationException(truncation);
+	attrs.add(attr);
+
 	attr = config.getProperty("structure." + rel);
 	if (attr == null)
 	    attr = config.getProperty("structure.*");
@@ -187,6 +200,15 @@ public String toPQF(Properties config) throws PQFTranslationException {
 	if (len > 0 && text.substring(len-1, len).equals("^"))
 	    text = text.substring(0, len-1);
 
+	len = text.length();
+	if (text.startsWith("*") && text.endsWith("*")) {
+	    text = text.substring(1, len-1);
+	} else if (text.startsWith("*")) {
+	    text = text.substring(1);
+	} else if (text.endsWith("*")) {
+	    text = text.substring(0, len-1);
+	}
+
 	return s + maybeQuote(text);
     }
 

src/main/java/org/z3950/zing/cql/UnknownTruncationException.java

@@ -0,0 +1,25 @@
+package org.z3950.zing.cql;
+
+/**
+ * Exception indicating that a truncation was not recognised. When rendering a
+ * tree out as PQF, each term is classified either as <TT>left</TT>,
+ * <TT>right</TT>, <TT>left and right</TT> truncated, depending on whether
+ * it begins and/or ends with the character <TT>*</TT>. Its
+ * classification is looked up as a <TT>truncation</TT> in the PQF
+ * configuration. If the truncation is not configured, we throw one of these
+ * babies.
+ *
+ */
+public class UnknownTruncationException extends PQFTranslationException {
+	private static final long serialVersionUID = 6971993723734811253L;
+
+	/**
+	 * Creates a new <TT>UnknownTruncationException</TT>.
+	 * 
+	 * @param s
+	 *            The truncation for which there was no PQF configuration.
+	 */
+	public UnknownTruncationException(String s) {
+		super(s);
+	}
+}