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>

4 files changed, 123 insertions, 6 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");
+        }
+    }
+
 }
diff --git a/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDataServiceImplSpec.groovy b/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDataServiceImplSpec.groovy
index 3f28f0ac8d..a53706a06b 100644
--- a/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDataServiceImplSpec.groovy
+++ b/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDataServiceImplSpec.groovy
@@ -188,7 +188,7 @@ class CpsDataServiceImplSpec extends Specification {
         expect: 'service returns same data if uses same parameters'
             objectUnderTest.getDataNode(dataspaceName, anchorName, xpath, fetchDescendantsOption) == dataNode
         where: 'all fetch options are supported'
-            fetchDescendantsOption << FetchDescendantsOption.values()
+            fetchDescendantsOption << [FetchDescendantsOption.OMIT_DESCENDANTS, FetchDescendantsOption.INCLUDE_ALL_DESCENDANTS]
     }
 
     def 'Get data node with option invalid #scenario.'() {
diff --git a/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsQueryServiceImplSpec.groovy b/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsQueryServiceImplSpec.groovy
index 55a252c27d..b7fec85119 100644
--- a/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsQueryServiceImplSpec.groovy
+++ b/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsQueryServiceImplSpec.groovy
@@ -1,6 +1,6 @@
 /*
  * ============LICENSE_START=======================================================
- *  Copyright (C) 2021 Nordix Foundation
+ *  Copyright (C) 2021-2022 Nordix Foundation
  *  ================================================================================
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -44,7 +44,7 @@ class CpsQueryServiceImplSpec extends Specification {
         then: 'the persistence service is called once with the correct parameters'
             1 * mockCpsDataPersistenceService.queryDataNodes(dataspaceName, anchorName, cpsPath, fetchDescendantsOption)
         where: 'all fetch descendants options are supported'
-            fetchDescendantsOption << FetchDescendantsOption.values()
+            fetchDescendantsOption << [FetchDescendantsOption.OMIT_DESCENDANTS, FetchDescendantsOption.INCLUDE_ALL_DESCENDANTS]
     }
 
     def 'Query data nodes by cps path with invalid #scenario.'() {
diff --git a/cps-service/src/test/groovy/org/onap/cps/spi/FetchDescendantsOptionSpec.groovy b/cps-service/src/test/groovy/org/onap/cps/spi/FetchDescendantsOptionSpec.groovy
new file mode 100644
index 0000000000..627383561a
--- /dev/null
+++ b/cps-service/src/test/groovy/org/onap/cps/spi/FetchDescendantsOptionSpec.groovy
@@ -0,0 +1,75 @@
+/*
+ * ============LICENSE_START=======================================================
+ *  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.
+ *  You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ *  ============LICENSE_END=========================================================
+ */
+
+package org.onap.cps.spi
+
+
+import spock.lang.Specification
+
+class FetchDescendantsOptionSpec extends Specification {
+    def 'Check has next descendant for fetch descendant option: #scenario'() {
+        when: 'fetch descendant option with #depth depth'
+            def fetchDescendantsOption = new FetchDescendantsOption(depth)
+        then: 'next level descendants available: #expectedHasNext'
+            fetchDescendantsOption.hasNext() == expectedHasNext
+        where: 'following parameters are used'
+            scenario                  | depth || expectedHasNext
+            'omit descendants'        | 0     || false
+            'first child'             | 1     || true
+            'second child'            | 2     || true
+            'include all descendants' | -1    || true
+    }
+
+    def 'Check has next descendant for fetch descendant option: invalid depth'() {
+        given: 'fetch descendant option with -2 depth'
+            def fetchDescendantsOption = new FetchDescendantsOption(-2)
+        when: 'next level descendants not available'
+            fetchDescendantsOption.hasNext()
+        then: 'exception thrown'
+            thrown IllegalArgumentException
+    }
+
+    def 'Get next descendant for fetch descendant option: #scenario'() {
+        when: 'fetch descendant option with #depth depth'
+            def fetchDescendantsOption = new FetchDescendantsOption(depth)
+        then: 'the next level of depth is as expected'
+            fetchDescendantsOption.next().depth == depth - 1
+        where: 'following parameters are used'
+            scenario                  | depth
+            'first child'             | 1
+            'second child'            | 2
+    }
+
+    def 'Get next descendant for fetch descendant option: include all descendants'() {
+        when: 'fetch descendant option with -1 depth'
+            def fetchDescendantsOption = new FetchDescendantsOption(-1)
+        then: 'the next level of depth is as expected'
+            fetchDescendantsOption.next().depth == -1
+    }
+
+    def 'Get next descendant for fetch descendant option: omit descendants'() {
+        given: 'fetch descendant option with 0 depth'
+            def fetchDescendantsOption = new FetchDescendantsOption(0)
+        when: 'the next level of depth is not allowed'
+            fetchDescendantsOption.next()
+        then: 'exception thrown'
+            thrown IllegalArgumentException
+    }
+}