Finish (more or less) to CQL-to-PQF translator.

[cql-java-moved-to-github.git] / src / org / z3950 / zing / cql / CQLProxNode.java

diff --git a/src/org/z3950/zing/cql/CQLProxNode.java b/src/org/z3950/zing/cql/CQLProxNode.java
index 1b9abe9..b3a8dca 100644 (file)
--- a/src/org/z3950/zing/cql/CQLProxNode.java
+++ b/src/org/z3950/zing/cql/CQLProxNode.java
@@ -1,37 +1,126 @@
-// $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;
     }
 }