-// $Id: CQLProxNode.java,v 1.1 2002-10-31 22:22:01 mike Exp $
+// $Id: CQLProxNode.java,v 1.3 2002-11-06 20:13:45 mike Exp $
package org.z3950.zing.cql;
+import java.util.Vector;
/**
* Represents a proximity node in a CQL parse-tree.
- * ##
+ * The left- and right-hand-sides must be satisfied by parts of the
+ * candidate records which are sufficiently close to each other, as
+ * specified by a set of proximity parameters.
*
- * @version $Id: CQLProxNode.java,v 1.1 2002-10-31 22:22:01 mike Exp $
+ * @version $Id: CQLProxNode.java,v 1.3 2002-11-06 20:13:45 mike Exp $
*/
public class CQLProxNode extends CQLBooleanNode {
ModifierSet ms;
+ /**
+ * Creates a new, <I>incomplete</I>, proximity node with the
+ * specified left-hand side. No right-hand side is specified at
+ * this stage: that must be specified later, using the
+ * <TT>addSecondSubterm()</TT> method. (That may seem odd, but
+ * it's just easier to write the parser that way.)
+ * <P>
+ * Proximity paramaters may be added at any time, before or after
+ * the right-hand-side sub-tree is added.
+ */
public CQLProxNode(CQLNode left) {
ms = new ModifierSet("prox");
this.left = left;
// this.right left unresolved for now ...
}
- // ... delayed "second half" of the constructor
+ /**
+ * Sets the right-hand side of the proximity node whose
+ * left-hand-side was specified at creation time.
+ */
public void addSecondSubterm(CQLNode right) {
this.right = right;
}
+ /**
+ * Adds a modifier of the specified <TT>type</TT> and
+ * <TT>value</TT> to a proximity node. Valid types are
+ * <TT>relation</TT>, <TT>distance</TT>, <TT>unit</TT> and
+ * <TT>ordering</TT>.
+ * <P>
+ * For information on the semantics of these paramaters, see
+ * <A href="http://zing.z3950.org/cql/intro.html#3.1"
+ * >section 3.1 (Proximity)</A> of
+ * <I>A Gentle Introduction to CQL</I></A>.
+ */
+ public void addModifier(String type, String value) {
+ ms.addModifier(type, value);
+ }
+
+ /**
+ * Returns an array of the modifiers associated with a proximity
+ * node.
+ * @return
+ * An array of modifiers, each represented by a two-element
+ * <TT>Vector</TT>, in which element 0 is the modifier type
+ * (e.g. <TT>distance</TT> or <TT>ordering</TT>) and element 1 is
+ * the associated value (e.g. <TT>3</TT> or <TT>unordered</TT>).
+ */
+ public Vector[] getModifiers() {
+ return ms.getModifiers();
+ }
+
String op() {
return ms.toCQL();
}
- public void addModifier(String type, String value) {
- ms.addModifier(type, value);
+ String opXQL(int level) {
+ return ms.toXCQL(level, "boolean");
}
- String booleanXQL(int level) {
- return ms.toXCQL(level, "boolean");
+ /*
+ * 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.
+ */
+ String opPQF() {
+ String rel = ms.modifier("relation");
+ int relCode = 0;
+ if (rel.equals("<")) {
+ relCode = 1;
+ } else if (rel.equals("<=")) {
+ relCode = 2;
+ } else if (rel.equals("=")) {
+ relCode = 3;
+ } else if (rel.equals(">=")) {
+ relCode = 4;
+ } else if (rel.equals(">")) {
+ relCode = 5;
+ } else if (rel.equals("<>")) {
+ relCode = 6;
+ }
+
+ String unit = ms.modifier("unit");
+ int unitCode = 0;
+ if (unit.equals("word")) {
+ unitCode = 2;
+ } else if (unit.equals("sentence")) {
+ unitCode = 3;
+ } else if (unit.equals("paragraph")) {
+ unitCode = 4;
+ } else if (unit.equals("element")) {
+ unitCode = 8;
+ }
+
+ String res = "prox " +
+ "0 " +
+ ms.modifier("distance") + " " +
+ (ms.modifier("ordering").equals("ordered") ? 1 : 0) + " " +
+ relCode + " " +
+ "1 " +
+ unitCode;
+
+ return res;
}
}