Fix Id-searches endpoint performance degradation

- create more flexible control over fetch descendants
- add a new FETCH_DIRECT_CHILDREN_ONLY option to fetch descendants
options
- enabel create custom fetch descendants option

Reviewer: Toine, Joe, Priyank
Issue-ID: CPS-1216
Change-Id: I900b32e813367aa9566c1dec986b20f009d27203
Signed-off-by: kissand <andras.zoltan.kiss@est.tech>

1 files changed, 45 insertions, 3 deletions

diff --git a/cps-service/src/main/java/org/onap/cps/spi/FetchDescendantsOption.java b/cps-service/src/main/java/org/onap/cps/spi/FetchDescendantsOption.java
index 0c994d8d7b..b80054ac3b 100644
--- a/cps-service/src/main/java/org/onap/cps/spi/FetchDescendantsOption.java
+++ b/cps-service/src/main/java/org/onap/cps/spi/FetchDescendantsOption.java
@@ -1,6 +1,7 @@
 /*
  *  ============LICENSE_START=======================================================
  *  Copyright (C) 2021 Pantheon.tech
+ *  Copyright (C) 2022 Nordix Foundation
  *  ================================================================================
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -19,7 +20,48 @@
 
 package org.onap.cps.spi;
 
-public enum FetchDescendantsOption {
-    OMIT_DESCENDANTS,
-    INCLUDE_ALL_DESCENDANTS
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+public class FetchDescendantsOption {
+
+    public static final FetchDescendantsOption FETCH_DIRECT_CHILDREN_ONLY = new FetchDescendantsOption(1);
+    public static final FetchDescendantsOption OMIT_DESCENDANTS = new FetchDescendantsOption(0);
+    public static final FetchDescendantsOption INCLUDE_ALL_DESCENDANTS = new FetchDescendantsOption(-1);
+
+    private final int depth;
+
+    /**
+     * Has next depth.
+     *
+     * @return true if next level of depth is available
+     * @throws IllegalArgumentException when depth less than -1
+     */
+    public boolean hasNext() {
+        validateDepth(depth);
+        return depth > 0 || this.depth == INCLUDE_ALL_DESCENDANTS.depth;
+    }
+
+    /**
+     * Next fetch descendants option.
+     *
+     * @return the next fetch descendants option
+     * @throws IllegalArgumentException when depth less than -1 or 0
+     */
+    public FetchDescendantsOption next() {
+        if (depth == 0) {
+            throw new IllegalArgumentException("Do not use next() method with zero depth");
+        }
+        final FetchDescendantsOption nextDescendantsOption = this.depth == INCLUDE_ALL_DESCENDANTS.depth
+                ? INCLUDE_ALL_DESCENDANTS : new FetchDescendantsOption(depth - 1);
+        validateDepth(nextDescendantsOption.depth);
+        return nextDescendantsOption;
+    }
+
+    private static void validateDepth(final int depth) {
+        if (depth < -1) {
+            throw new IllegalArgumentException("A depth of less than minus one is not allowed");
+        }
+    }
+
 }