[Cps Path Parser] Introduce Attribute axis

Add grammar and tests for attribute-axis to match cps paths like:

  //books/@title

which should return the titles of all books (a subsequent patch will
implement the logic). The syntax is compatible with XPath standard.

Issue-ID: CPS-2416
Signed-off-by: danielhanrahan <daniel.hanrahan@est.tech>
Change-Id: I25164b23670147c504f0f0f6c0cc8ff15997f2a3

2 files changed, 17 insertions, 0 deletions

diff --git a/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathBuilder.java b/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathBuilder.java
index b67d70847c..d0deb7defc 100644
--- a/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathBuilder.java
+++ b/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathBuilder.java
@@ -131,6 +131,13 @@ public class CpsPathBuilder extends CpsPathBaseListener {
     }
 
     @Override
+    public void exitAttributeAxis(final CpsPathParser.AttributeAxisContext ctx) {
+        final String attributeName = ctx.leafName().getText();
+        normalizedXpathBuilder.append("/@").append(attributeName);
+        cpsPathQuery.setAttributeAxisAttributeName(attributeName);
+    }
+
+    @Override
     public void exitTextFunctionCondition(final TextFunctionConditionContext ctx) {
         cpsPathQuery.setTextFunctionConditionLeafName(ctx.leafName().getText());
         cpsPathQuery.setTextFunctionConditionValue(unwrapQuotedString(ctx.StringLiteral().getText()));
diff --git a/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathQuery.java b/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathQuery.java
index 03602b64f6..3612ec57fb 100644
--- a/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathQuery.java
+++ b/cps-path-parser/src/main/java/org/onap/cps/cpspath/parser/CpsPathQuery.java
@@ -40,6 +40,7 @@ public class CpsPathQuery {
     private String descendantName;
     private List<LeafCondition> leafConditions;
     private String ancestorSchemaNodeIdentifier = "";
+    private String attributeAxisAttributeName = "";
     private String textFunctionConditionLeafName;
     private String textFunctionConditionValue;
     private List<String> booleanOperators;
@@ -66,6 +67,15 @@ public class CpsPathQuery {
     }
 
     /**
+     * Has attribute axis been included in cpsPath.
+     *
+     * @return boolean value.
+     */
+    public boolean hasAttributeAxis() {
+        return !(attributeAxisAttributeName.isEmpty());
+    }
+
+    /**
      * Have leaf value conditions been included in cpsPath.
      *
      * @return boolean value.