CAY-2837 Deprecate TraversalHelper and move no-op implementations to …

…TraversalHandler
apache · Jan 23, 2024 · d43d291 · d43d291
1 parent 3469340
commit d43d291
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Showing 7 changed files with 17 additions and 34 deletions.
diff --git a/RELEASE-NOTES.txt b/RELEASE-NOTES.txt
@@ -62,6 +62,7 @@ CAY-2829 Merge `BaseContext` with `DataContext` and deprecate it
 CAY-2830 Cleanup `DataContext` code
 CAY-2831 Upgrade Gradle to 8.5
 CAY-2834 v11 upgrade handler should update XMLPoolingDataSourceFactory package
+CAY-2837 Deprecate TraversalHelper and move no-op implementations to TraversalHandler
 
 Bug Fixes:
 

diff --git a/cayenne/src/main/java/org/apache/cayenne/access/translator/select/QualifierTranslator.java b/cayenne/src/main/java/org/apache/cayenne/access/translator/select/QualifierTranslator.java
@@ -473,10 +473,6 @@ protected DbAttribute findDbAttribute(Expression node) {
         return result.getLastAttribute();
     }
 
-    @Override
-    public void finishedChild(Expression node, int childIndex, boolean hasMoreChildren) {
-    }
-
     private String expToStr(int type) {
         switch (type) {
             case AND:

diff --git a/cayenne/src/main/java/org/apache/cayenne/exp/Expression.java b/cayenne/src/main/java/org/apache/cayenne/exp/Expression.java
@@ -813,7 +813,7 @@ public Object apply(Object object) {
 
 	}
 
-	final class InPlaceParamReplacer extends TraversalHelper {
+	final class InPlaceParamReplacer implements TraversalHandler {
 
 		private Object[] parameters;
 		private int i;

diff --git a/cayenne/src/main/java/org/apache/cayenne/exp/TraversalHandler.java b/cayenne/src/main/java/org/apache/cayenne/exp/TraversalHandler.java
@@ -30,30 +30,34 @@ public interface TraversalHandler {
      * Called during traversal after a child of expression
      * has been visited. 
      */
-    public void finishedChild(
+    default void finishedChild(
         Expression node,
         int childIndex,
-        boolean hasMoreChildren);
+        boolean hasMoreChildren) {
+    }
 
     /** 
      * Called during the traversal before an expression node children
      * processing is started.
      * 
      * @since 1.1
      */
-    public void startNode(Expression node, Expression parentNode);
+    default void startNode(Expression node, Expression parentNode) {
+    }
 
     /** 
      * Called during the traversal after an expression node children
      * processing is finished.
      * 
      * @since 1.1
      */
-    public void endNode(Expression node, Expression parentNode);
+    default void endNode(Expression node, Expression parentNode) {
+    }
 
     /** 
      * Called during the traversal when a leaf non-expression node 
      * is encountered.
      */
-    public void objectNode(Object leaf, Expression parentNode);
+    default void objectNode(Object leaf, Expression parentNode) {
+    }
 }
diff --git a/cayenne/src/main/java/org/apache/cayenne/exp/TraversalHelper.java b/cayenne/src/main/java/org/apache/cayenne/exp/TraversalHelper.java
@@ -23,19 +23,9 @@
  * Noop implementation of TraversalHandler. 
  * Useful as a superclass for partial implementations 
  * of TraversalHandler. 
- * 
+ *
+ * @deprecated since 5.0 as {@link TraversalHandler} has default no-op implementations for all methods
  */
+@Deprecated(since = "5.0", forRemoval = true)
 public class TraversalHelper implements TraversalHandler {
-
-    public void startNode(Expression node, Expression parentNode) {
-    }
-
-    public void endNode(Expression node, Expression parentNode) {
-    }
-
-    public void finishedChild(Expression node, int childIndex, boolean hasMoreChildren) {
-    }
-
-    public void objectNode(Object leaf, Expression parentNode) {
-    }  
 }
diff --git a/cayenne/src/main/java/org/apache/cayenne/reflect/PersistentDescriptorFactory.java b/cayenne/src/main/java/org/apache/cayenne/reflect/PersistentDescriptorFactory.java
@@ -26,7 +26,7 @@
 import org.apache.cayenne.CayenneRuntimeException;
 import org.apache.cayenne.dba.TypesMapping;
 import org.apache.cayenne.exp.Expression;
-import org.apache.cayenne.exp.TraversalHelper;
+import org.apache.cayenne.exp.TraversalHandler;
 import org.apache.cayenne.map.DbAttribute;
 import org.apache.cayenne.map.DbEntity;
 import org.apache.cayenne.map.DbRelationship;
@@ -222,7 +222,7 @@ protected void indexQualifiers(final PersistentDescriptor descriptor, EntityInhe
             final Map<String, ObjAttribute> attributes = new HashMap<>();
             final DbEntity dbEntity = descriptor.getEntity().getDbEntity();
 
-            qualifier.traverse(new TraversalHelper() {
+            qualifier.traverse(new TraversalHandler() {
 
                 @Override
                 public void startNode(Expression node, Expression parentNode) {

diff --git a/cayenne/src/test/java/org/apache/cayenne/exp/TstTraversalHandler.java b/cayenne/src/test/java/org/apache/cayenne/exp/TstTraversalHandler.java
@@ -30,7 +30,7 @@
  * Class that collects statistics of expression traversal.
  */
 public class TstTraversalHandler implements TraversalHandler {
-	protected List<Object> treeFlatView = new ArrayList<Object>();
+	protected List<Object> treeFlatView = new ArrayList<>();
 	protected int children;
 	protected int nodes;
 	protected int nodesStarted;
@@ -58,10 +58,6 @@ public void assertConsistency() {
 		Assert.assertEquals(nodesStarted, nodes);
 	}
 
-	public List<Object> getTreeFlatView() {
-		return treeFlatView;
-	}
-
 	public void traverseExpression(Expression exp) {
 		reset();
 		exp.traverse(this);
@@ -86,10 +82,6 @@ public int getNodes() {
 		return nodes;
 	}
 
-	public int getNodesStarted() {
-		return nodesStarted;
-	}
-
 	public int getLeafs() {
 		return leafs;
 	}