Add classes for visitor traversal

diff --git a/src/main/java/org/z3950/zing/cql/CQLAndNode.java b/src/main/java/org/z3950/zing/cql/CQLAndNode.java
index 7e39669..6b95630 100644 (file)
--- a/src/main/java/org/z3950/zing/cql/CQLAndNode.java
+++ b/src/main/java/org/z3950/zing/cql/CQLAndNode.java
@@ -15,6 +15,13 @@ public class CQLAndNode extends CQLBooleanNode {
        super(left, right, ms);
     }
 
+    @Override
+    public void traverse(CQLNodeVisitor visitor) {
+      visitor.onAndNode(this);
+      super.traverse(visitor);
+    }
+    
+
     // ### Too much code duplication here with OR and NOT
     @Override
     byte[] opType1() {

diff --git a/src/main/java/org/z3950/zing/cql/CQLBooleanNode.java b/src/main/java/org/z3950/zing/cql/CQLBooleanNode.java
index 18c0bff..1b73ee7 100644 (file)
--- a/src/main/java/org/z3950/zing/cql/CQLBooleanNode.java
+++ b/src/main/java/org/z3950/zing/cql/CQLBooleanNode.java
@@ -43,6 +43,14 @@ public abstract class CQLBooleanNode extends CQLNode {
     }
 
     @Override
+    public void traverse(CQLNodeVisitor visitor) {
+      visitor.onBooleanNode(this);
+      left.traverse(visitor);
+      right.traverse(visitor);
+    }
+
+
+    @Override
     void toXCQLInternal(XCQLBuilder b, int level,
         List<CQLPrefix> prefixes, List<ModifierSet> sortkeys) {
        b.indent(level).append("<triple>\n");

diff --git a/src/main/java/org/z3950/zing/cql/CQLDefaultNodeVisitor.java b/src/main/java/org/z3950/zing/cql/CQLDefaultNodeVisitor.java
new file mode 100644 (file)
index 0000000..d77dafb
--- /dev/null
+++ b/src/main/java/org/z3950/zing/cql/CQLDefaultNodeVisitor.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 1995-2014, Index Data
+ * All rights reserved.
+ * See the file LICENSE for details.
+ */
+
+package org.z3950.zing.cql;
+
+/**
+ * Query tree visitor with default (no-op) implementation
+ * @author jakub
+ */
+public class CQLDefaultNodeVisitor implements CQLNodeVisitor {
+
+  @Override
+  public void onSortNode(CQLSortNode node) {
+  }
+
+  @Override
+  public void onPrfixNode(CQLPrefixNode node) {
+  }
+
+  @Override
+  public void onBooleanNode(CQLBooleanNode node) {
+  }
+
+  @Override
+  public void onProxNode(CQLProxNode node) {
+  }
+
+  @Override
+  public void onAndNode(CQLAndNode node) {
+  }
+
+  @Override
+  public void onOrNode(CQLOrNode node) {
+  }
+
+  @Override
+  public void onNotNode(CQLNotNode node) {
+  }
+
+  @Override
+  public void onTermNode(CQLTermNode node) {
+  }
+
+  @Override
+  public void onRelation(CQLRelation relation) {
+  }
+  
+}

diff --git a/src/main/java/org/z3950/zing/cql/CQLNode.java b/src/main/java/org/z3950/zing/cql/CQLNode.java
index a4e171d..221da44 100644 (file)
--- a/src/main/java/org/z3950/zing/cql/CQLNode.java
+++ b/src/main/java/org/z3950/zing/cql/CQLNode.java
@@ -12,6 +12,8 @@ import java.util.Properties;
  *
  */
 public abstract class CQLNode {
+  
+    public abstract void traverse(CQLNodeVisitor visitor);
 
     /**
      * Returns the name of the result-set to which this query is a

diff --git a/src/main/java/org/z3950/zing/cql/CQLNodeVisitor.java b/src/main/java/org/z3950/zing/cql/CQLNodeVisitor.java
new file mode 100644 (file)
index 0000000..0d120d8
--- /dev/null
+++ b/src/main/java/org/z3950/zing/cql/CQLNodeVisitor.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 1995-2014, Index Data
+ * All rights reserved.
+ * See the file LICENSE for details.
+ */
+
+package org.z3950.zing.cql;
+
+/**
+ * Allows to visit different types of nodes in the query tree.
+ * @author jakub
+ */
+public interface CQLNodeVisitor {
+  
+  public void onSortNode(CQLSortNode node);
+  
+  public void onPrfixNode(CQLPrefixNode node);
+  
+  public void onBooleanNode(CQLBooleanNode node);
+  
+  public void onProxNode(CQLProxNode node);
+  
+  public void onAndNode(CQLAndNode node);
+  
+  public void onOrNode(CQLOrNode node);
+  
+  public void onNotNode(CQLNotNode node);
+  
+  public void onTermNode(CQLTermNode node);
+  
+  public void onRelation(CQLRelation relation);
+  
+}

diff --git a/src/main/java/org/z3950/zing/cql/CQLNotNode.java b/src/main/java/org/z3950/zing/cql/CQLNotNode.java
index 4f3814c..c32d427 100644 (file)
--- a/src/main/java/org/z3950/zing/cql/CQLNotNode.java
+++ b/src/main/java/org/z3950/zing/cql/CQLNotNode.java
@@ -16,6 +16,12 @@ public class CQLNotNode extends CQLBooleanNode {
     }
 
     @Override
+    public void traverse(CQLNodeVisitor visitor) {
+      visitor.onNotNode(this);
+      super.traverse(visitor);
+    }    
+
+    @Override
     byte[] opType1() {
        byte[] op = new byte[5];
        putTag(CONTEXT, 46, CONSTRUCTED, op, 0); // Operator

diff --git a/src/main/java/org/z3950/zing/cql/CQLOrNode.java b/src/main/java/org/z3950/zing/cql/CQLOrNode.java
index 92c9dfa..52fd899 100644 (file)
--- a/src/main/java/org/z3950/zing/cql/CQLOrNode.java
+++ b/src/main/java/org/z3950/zing/cql/CQLOrNode.java
@@ -16,6 +16,12 @@ public class CQLOrNode extends CQLBooleanNode {
     }
 
     @Override
+    public void traverse(CQLNodeVisitor visitor) {
+      visitor.onOrNode(this);
+      super.traverse(visitor);
+    }
+
+    @Override
     byte[] opType1() {
        byte[] op = new byte[5];
        putTag(CONTEXT, 46, CONSTRUCTED, op, 0); // Operator

diff --git a/src/main/java/org/z3950/zing/cql/CQLPrefixNode.java b/src/main/java/org/z3950/zing/cql/CQLPrefixNode.java
index d3f6b74..2b23a6d 100644 (file)
--- a/src/main/java/org/z3950/zing/cql/CQLPrefixNode.java
+++ b/src/main/java/org/z3950/zing/cql/CQLPrefixNode.java
@@ -41,6 +41,12 @@ public class CQLPrefixNode extends CQLNode {
     }
 
     @Override
+    public void traverse(CQLNodeVisitor visitor) {
+      visitor.onPrfixNode(this);
+      subtree.traverse(visitor);
+    }
+
+    @Override
     void toXCQLInternal(XCQLBuilder b, int level, List<CQLPrefix> prefixes,
                         List<ModifierSet> sortkeys) {
        List<CQLPrefix> tmp = (prefixes == null ?

diff --git a/src/main/java/org/z3950/zing/cql/CQLProxNode.java b/src/main/java/org/z3950/zing/cql/CQLProxNode.java
index 35f1781..c33eade 100644 (file)
--- a/src/main/java/org/z3950/zing/cql/CQLProxNode.java
+++ b/src/main/java/org/z3950/zing/cql/CQLProxNode.java
@@ -18,6 +18,11 @@ public class CQLProxNode extends CQLBooleanNode {
        super(left, right, ms);
     }
 
+    @Override
+    public void traverse(CQLNodeVisitor visitor) {
+      visitor.onProxNode(this);
+    }    
+
     /*
      * proximity ::= exclusion distance ordered relation which-code unit-code.
      * exclusion ::= '1' | '0' | 'void'.

diff --git a/src/main/java/org/z3950/zing/cql/CQLRelation.java b/src/main/java/org/z3950/zing/cql/CQLRelation.java
index 716a1e9..81fd38c 100644 (file)
--- a/src/main/java/org/z3950/zing/cql/CQLRelation.java
+++ b/src/main/java/org/z3950/zing/cql/CQLRelation.java
@@ -42,6 +42,11 @@ public class CQLRelation extends CQLNode {
     }
 
     @Override
+    public void traverse(CQLNodeVisitor visitor) {
+      visitor.onRelation(this);
+    } 
+    
+    @Override
     void toXCQLInternal(XCQLBuilder b, int level, List<CQLPrefix> prefixes,
       List<ModifierSet> sortkeys) {
        if (sortkeys != null)

diff --git a/src/main/java/org/z3950/zing/cql/CQLSortNode.java b/src/main/java/org/z3950/zing/cql/CQLSortNode.java
index 96a93e8..efc190b 100644 (file)
--- a/src/main/java/org/z3950/zing/cql/CQLSortNode.java
+++ b/src/main/java/org/z3950/zing/cql/CQLSortNode.java
@@ -41,6 +41,12 @@ public class CQLSortNode extends CQLNode {
     }
 
     @Override
+    public void traverse(CQLNodeVisitor visitor) {
+      visitor.onSortNode(this);
+      subtree.traverse(visitor);
+    }
+
+    @Override
     void toXCQLInternal(XCQLBuilder b, int level, List<CQLPrefix> prefixes,
                         List<ModifierSet> sortkeys) {
        if (sortkeys != null)

diff --git a/src/main/java/org/z3950/zing/cql/CQLTermNode.java b/src/main/java/org/z3950/zing/cql/CQLTermNode.java
index a6e1772..2ad9188 100644 (file)
--- a/src/main/java/org/z3950/zing/cql/CQLTermNode.java
+++ b/src/main/java/org/z3950/zing/cql/CQLTermNode.java
@@ -42,6 +42,13 @@ public class CQLTermNode extends CQLNode {
     }
 
     @Override
+    public void traverse(CQLNodeVisitor visitor) {
+      //we visit relation first to allow filtering on relation type in the visitor
+      relation.traverse(visitor);
+      visitor.onTermNode(this);
+    }
+        
+    @Override
     public String getResultSetName() {
        if (isResultSetIndex(index))
            return term;