From 32789498e82bbbf0c81f1253753831c46ab076b7 Mon Sep 17 00:00:00 2001
From: Giuseppe Villani <giuseppe.villani@larus-ba.it>
Date: Thu, 13 Jan 2022 13:10:44 +0100
Subject: [PATCH] Fixes #577: return apoc.nodes.count(['User']) (#2277)

---
 core/src/main/java/apoc/meta/Meta.java        | 47 +++++++++++++
 core/src/test/java/apoc/meta/MetaTest.java    | 46 ++++++++++++-
 .../apoc.meta.nodes-lite.csv                  |  2 +
 .../apoc.meta.nodes.count-lite.csv            |  2 +
 .../apoc.meta.nodes.count.adoc                |  5 ++
 .../apoc.meta.nodes.csv                       |  6 ++
 .../generated-documentation/documentation.csv |  1 +
 .../apoc.meta/apoc.meta.nodes.count.adoc      | 34 ++++++++++
 .../ROOT/pages/overview/apoc.meta/index.adoc  |  5 ++
 .../documentation.adoc                        |  5 ++
 .../partials/generated-documentation/nav.adoc |  1 +
 .../partials/usage/apoc.meta.nodes.count.adoc | 66 +++++++++++++++++++
 .../usage/config/apoc.meta.nodes.count.adoc   |  9 +++
 13 files changed, 228 insertions(+), 1 deletion(-)
 create mode 100644 docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes-lite.csv
 create mode 100644 docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.count-lite.csv
 create mode 100644 docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.count.adoc
 create mode 100644 docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.csv
 create mode 100644 docs/asciidoc/modules/ROOT/pages/overview/apoc.meta/apoc.meta.nodes.count.adoc
 create mode 100644 docs/asciidoc/modules/ROOT/partials/usage/apoc.meta.nodes.count.adoc
 create mode 100644 docs/asciidoc/modules/ROOT/partials/usage/config/apoc.meta.nodes.count.adoc

diff --git a/core/src/main/java/apoc/meta/Meta.java b/core/src/main/java/apoc/meta/Meta.java
index f94ccd8206..98399cf515 100644
--- a/core/src/main/java/apoc/meta/Meta.java
+++ b/core/src/main/java/apoc/meta/Meta.java
@@ -58,6 +58,7 @@
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import java.util.TreeMap;
 import java.util.concurrent.ThreadLocalRandom;
@@ -372,6 +373,52 @@ public Stream<MetaStats> stats() {
         return Stream.of(collectStats());
     }
 
+    @UserFunction(name = "apoc.meta.nodes.count")
+    @Description("apoc.meta.nodes.count([labels], $config) - Returns the sum of the nodes with a label present in the list.")
+    public long count(@Name(value = "nodes", defaultValue = "[]") List<String> nodes, @Name(value = "config", defaultValue = "{}") Map<String, Object> config) {
+        MetaConfig conf = new MetaConfig(config);
+        final DatabaseSubGraph subGraph = new DatabaseSubGraph(transaction);
+        Stream<Label> labels = CollectionUtils.isEmpty(nodes)
+                ? StreamSupport.stream(subGraph.getAllLabelsInUse().spliterator(), false)
+                : nodes.stream().filter(Objects::nonNull).map(String::trim).map(Label::label);
+
+        final boolean isIncludeRels = CollectionUtils.isEmpty(conf.getIncludesRels());
+        Set<Long> visitedNodes = new HashSet<>();
+        return labels
+                .flatMap(label -> isIncludeRels ? Stream.of(subGraph.countsForNode(label)) : conf.getIncludesRels()
+                        .stream()
+                        .filter(Objects::nonNull)
+                        .map(String::trim)
+                        .map(rel -> {
+                            final int lastCharIdx = rel.length() - 1;
+                            final Direction direction;
+                            switch (rel.charAt(lastCharIdx)) {
+                                case '>':
+                                    direction = Direction.OUTGOING;
+                                    rel = rel.substring(0, lastCharIdx);
+                                    break;
+                                case '<':
+                                    direction = Direction.INCOMING;
+                                    rel = rel.substring(0, lastCharIdx);
+                                    break;
+                                default:
+                                    direction = Direction.BOTH;
+                            }
+                            return Pair.of(direction, rel);
+                        })
+                        .flatMap(pair -> transaction.findNodes(label)
+                                .map(node -> {
+                                    if (!visitedNodes.contains(node.getId()) && node.hasRelationship(pair.first(), RelationshipType.withName(pair.other()))) {
+                                        visitedNodes.add(node.getId());
+                                        return 1L;
+                                    } else {
+                                        return 0L;
+                                    }
+                                })
+                                .stream()))
+                .reduce(0L, Math::addExact);
+    }
+
     private MetaStats collectStats() {
         Map<String, Long> relStatsCount = new LinkedHashMap<>();
         TokenRead tokenRead = kernelTx.tokenRead();
diff --git a/core/src/test/java/apoc/meta/MetaTest.java b/core/src/test/java/apoc/meta/MetaTest.java
index 8c6cedc7c6..2539d1a194 100644
--- a/core/src/test/java/apoc/meta/MetaTest.java
+++ b/core/src/test/java/apoc/meta/MetaTest.java
@@ -1407,5 +1407,49 @@ public void testMetaStatsWithLabelAndRelTypeCountInUse() {
             assertEquals(expectedRelTypes, row.get("relTypes"));
         });
     }
-    
+
+    @Test
+    public void testMetaNodesCount() {
+        db.executeTransactionally("CREATE (:MyCountLabel {id: 1}), (:MyCountLabel {id: 2}), (:ThirdLabel {id: 3})");
+
+        // 2 outcome rels and 1 incoming
+        db.executeTransactionally("MATCH (n:MyCountLabel {id: 1}), (m:ThirdLabel {id: 3}) " +
+                "CREATE (n)-[:MY_COUNT_REL]->(m), (n)-[:ANOTHER_MY_COUNT_REL]->(m), (n)<-[:ANOTHER_MY_COUNT_REL]-(m)");
+
+        TestUtil.testCall(db, "RETURN apoc.meta.nodes.count(['MyCountLabel'], {rels: ['MY_COUNT_REL']}) AS count",
+                row -> assertEquals(1L, row.get("count")));
+
+        TestUtil.testCall(db, "RETURN apoc.meta.nodes.count(['MyCountLabel', 'NotExistent'], {rels: ['MY_COUNT_REL']}) AS count",
+                row -> assertEquals(1L, row.get("count")));
+
+        TestUtil.testCall(db, "RETURN apoc.meta.nodes.count(['MyCountLabel'], {rels: ['MY_COUNT_REL>']}) AS count",
+                row -> assertEquals(1L, row.get("count")));
+
+        TestUtil.testCall(db, "RETURN apoc.meta.nodes.count(['MyCountLabel'], {rels: ['MY_COUNT_REL<']}) AS count",
+                row -> assertEquals(0L, row.get("count")));
+
+        TestUtil.testCall(db, "RETURN apoc.meta.nodes.count(['MyCountLabel'], {rels: ['MY_COUNT_REL', 'ANOTHER_MY_COUNT_REL']}) AS count",
+                row -> assertEquals(1L, row.get("count")));
+
+        // another 2 nodes with 2 new labels
+        db.executeTransactionally("CREATE (:AnotherCountLabel)<-[:MY_COUNT_REL]-(:NotInCountLabel)");
+
+        TestUtil.testCall(db, "RETURN apoc.meta.nodes.count(['MyCountLabel', 'AnotherCountLabel'], {rels: ['MY_COUNT_REL', 'ANOTHER_MY_COUNT_REL']}) AS count",
+                row -> assertEquals(2L, row.get("count")));
+
+        // create another 2 rels in `MyCountLabel` nodes
+        db.executeTransactionally("MATCH (n:MyCountLabel) WITH n CREATE (n)<-[:MY_COUNT_REL]-(:NotInCountLabel)");
+
+        TestUtil.testCall(db, "RETURN apoc.meta.nodes.count(['MyCountLabel', 'AnotherCountLabel'], {rels: ['MY_COUNT_REL', 'ANOTHER_MY_COUNT_REL']}) AS count",
+                row -> assertEquals(3L, row.get("count")));
+
+        TestUtil.testCall(db, "RETURN apoc.meta.nodes.count(['MyCountLabel', 'AnotherCountLabel'], {rels: ['MY_COUNT_REL', 'ANOTHER_MY_COUNT_REL']}) AS count",
+                row -> assertEquals(3L, row.get("count")));
+
+        // just to check that with both direction takes all
+        TestUtil.testCall(db, "RETURN apoc.meta.nodes.count(['MyCountLabel', 'AnotherCountLabel'], {rels: ['MY_COUNT_REL>', 'MY_COUNT_REL<', 'ANOTHER_MY_COUNT_REL']}) AS count",
+                row -> assertEquals(3L, row.get("count")));
+        
+    }
+
 }
diff --git a/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes-lite.csv b/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes-lite.csv
new file mode 100644
index 0000000000..0c26a4cff5
--- /dev/null
+++ b/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes-lite.csv
@@ -0,0 +1,2 @@
+¦signature
+¦apoc.meta.nodes.count(nodes = [] :: LIST? OF STRING?, config = {} :: MAP?) :: (INTEGER?)
diff --git a/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.count-lite.csv b/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.count-lite.csv
new file mode 100644
index 0000000000..0c26a4cff5
--- /dev/null
+++ b/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.count-lite.csv
@@ -0,0 +1,2 @@
+¦signature
+¦apoc.meta.nodes.count(nodes = [] :: LIST? OF STRING?, config = {} :: MAP?) :: (INTEGER?)
diff --git a/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.count.adoc b/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.count.adoc
new file mode 100644
index 0000000000..ec3eaffae8
--- /dev/null
+++ b/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.count.adoc
@@ -0,0 +1,5 @@
+¦xref::overview/apoc.meta/apoc.meta.nodes.count.adoc[apoc.meta.nodes.count icon:book[]] +
+
+ - Returns the sum of the nodes with a label present in the list.
+¦label:function[]
+¦label:apoc-core[]
diff --git a/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.csv b/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.csv
new file mode 100644
index 0000000000..bd0e3ef54a
--- /dev/null
+++ b/docs/asciidoc/modules/ROOT/examples/generated-documentation/apoc.meta.nodes.csv
@@ -0,0 +1,6 @@
+¦Qualified Name¦Type¦Release
+|xref::overview/apoc.meta.nodes/apoc.meta.adoc[apoc.meta.nodes.count icon:book[]]
+
+apoc.meta.nodes.count([labels], $config) - Returns the sum of the nodes with a label present in the list.
+|label:function[]
+|label:apoc-core[]
diff --git a/docs/asciidoc/modules/ROOT/examples/generated-documentation/documentation.csv b/docs/asciidoc/modules/ROOT/examples/generated-documentation/documentation.csv
index 74d808aabe..d1190e801c 100644
--- a/docs/asciidoc/modules/ROOT/examples/generated-documentation/documentation.csv
+++ b/docs/asciidoc/modules/ROOT/examples/generated-documentation/documentation.csv
@@ -493,6 +493,7 @@ for the provided `label` and `uuidProperty`, in case the UUID handler is already
 ¦function¦apoc.meta.cypher.type¦apoc.meta.cypher.type(value :: ANY?) :: (STRING?)¦apoc.meta.cypher.type(value) - type name of a value (INTEGER,FLOAT,STRING,BOOLEAN,RELATIONSHIP,NODE,PATH,NULL,MAP,LIST OF <TYPE>,POINT,DATE,DATE_TIME,LOCAL_TIME,LOCAL_DATE_TIME,TIME,DURATION)¦true¦
 ¦function¦apoc.meta.cypher.types¦apoc.meta.cypher.types(properties :: ANY?) :: (MAP?)¦apoc.meta.cypher.types(node-relationship-map)  - returns a map of keys to types¦true¦
 ¦function¦apoc.meta.isType¦apoc.meta.isType(value :: ANY?, type :: STRING?) :: (BOOLEAN?)¦apoc.meta.isType(value,type) - returns a row if type name matches none if not (INTEGER,FLOAT,STRING,BOOLEAN,RELATIONSHIP,NODE,PATH,NULL,UNKNOWN,MAP,LIST)¦true¦
+¦function¦apoc.meta.nodes.count¦apoc.meta.nodes.count(nodes = [] :: LIST? OF STRING?, config = {} :: MAP?) :: (INTEGER?)¦apoc.meta.nodes.count([labels], $config) - Returns the sum of the nodes with a label present in the list.¦true¦
 ¦function¦apoc.meta.type¦apoc.meta.type(value :: ANY?) :: (STRING?)¦apoc.meta.type(value) - type name of a value (INTEGER,FLOAT,STRING,BOOLEAN,RELATIONSHIP,NODE,PATH,NULL,UNKNOWN,MAP,LIST)¦true¦
 ¦function¦apoc.meta.typeName¦apoc.meta.typeName(value :: ANY?) :: (STRING?)¦apoc.meta.typeName(value) - type name of a value (INTEGER,FLOAT,STRING,BOOLEAN,RELATIONSHIP,NODE,PATH,NULL,UNKNOWN,MAP,LIST)¦true¦
 ¦function¦apoc.meta.types¦apoc.meta.types(properties :: ANY?) :: (MAP?)¦apoc.meta.types(node-relationship-map)  - returns a map of keys to types¦true¦
diff --git a/docs/asciidoc/modules/ROOT/pages/overview/apoc.meta/apoc.meta.nodes.count.adoc b/docs/asciidoc/modules/ROOT/pages/overview/apoc.meta/apoc.meta.nodes.count.adoc
new file mode 100644
index 0000000000..af448af05e
--- /dev/null
+++ b/docs/asciidoc/modules/ROOT/pages/overview/apoc.meta/apoc.meta.nodes.count.adoc
@@ -0,0 +1,34 @@
+////
+This file is generated by DocsTest, so don't change it!
+////
+
+= apoc.meta.nodes.count
+:description: This section contains reference documentation for the apoc.meta.nodes.count function.
+
+label:function[] label:apoc-core[]
+
+[.emphasis]
+apoc.meta.nodes.count([labels], $config) - Returns the sum of the nodes with a label present in the list.
+
+== Signature
+
+[source]
+----
+apoc.meta.nodes.count(nodes = [] :: LIST? OF STRING?, config = {} :: MAP?) :: (INTEGER?)
+----
+
+== Input parameters
+[.procedures, opts=header]
+|===
+| Name | Type | Default 
+|nodes|LIST? OF STRING?|[]
+|config|MAP?|{}
+|===
+
+== Config parameters
+include::partial$usage/config/apoc.meta.nodes.count.adoc[]
+
+[[usage-apoc.meta.nodes.count]]
+== Usage Examples
+include::partial$usage/apoc.meta.nodes.count.adoc[]
+
diff --git a/docs/asciidoc/modules/ROOT/pages/overview/apoc.meta/index.adoc b/docs/asciidoc/modules/ROOT/pages/overview/apoc.meta/index.adoc
index 07e0af12d4..1488e5bb1c 100644
--- a/docs/asciidoc/modules/ROOT/pages/overview/apoc.meta/index.adoc
+++ b/docs/asciidoc/modules/ROOT/pages/overview/apoc.meta/index.adoc
@@ -78,6 +78,11 @@ apoc.meta.cypher.types(node-relationship-map)  - returns a map of keys to types
 apoc.meta.isType(value,type) - returns a row if type name matches none if not (INTEGER,FLOAT,STRING,BOOLEAN,RELATIONSHIP,NODE,PATH,NULL,UNKNOWN,MAP,LIST)
 |label:function[]
 |label:apoc-core[]
+|xref::overview/apoc.meta/apoc.meta.nodes.count.adoc[apoc.meta.nodes.count icon:book[]]
+
+apoc.meta.nodes.count([labels], $config) - Returns the sum of the nodes with a label present in the list.
+|label:function[]
+|label:apoc-core[]
 |xref::overview/apoc.meta/apoc.meta.type.adoc[apoc.meta.type icon:book[]]
 
 apoc.meta.type(value) - type name of a value (INTEGER,FLOAT,STRING,BOOLEAN,RELATIONSHIP,NODE,PATH,NULL,UNKNOWN,MAP,LIST)
diff --git a/docs/asciidoc/modules/ROOT/partials/generated-documentation/documentation.adoc b/docs/asciidoc/modules/ROOT/partials/generated-documentation/documentation.adoc
index aaa5072a27..4e82fa8bc3 100644
--- a/docs/asciidoc/modules/ROOT/partials/generated-documentation/documentation.adoc
+++ b/docs/asciidoc/modules/ROOT/partials/generated-documentation/documentation.adoc
@@ -2002,6 +2002,11 @@ apoc.meta.cypher.types(node-relationship-map)  - returns a map of keys to types
 apoc.meta.isType(value,type) - returns a row if type name matches none if not (INTEGER,FLOAT,STRING,BOOLEAN,RELATIONSHIP,NODE,PATH,NULL,UNKNOWN,MAP,LIST)
 |label:function[]
 |label:apoc-core[]
+|xref::overview/apoc.meta/apoc.meta.nodes.count.adoc[apoc.meta.nodes.count icon:book[]]
+
+apoc.meta.nodes.count([labels], $config) - Returns the sum of the nodes with a label present in the list.
+|label:function[]
+|label:apoc-core[]
 |xref::overview/apoc.meta/apoc.meta.type.adoc[apoc.meta.type icon:book[]]
 
 apoc.meta.type(value) - type name of a value (INTEGER,FLOAT,STRING,BOOLEAN,RELATIONSHIP,NODE,PATH,NULL,UNKNOWN,MAP,LIST)
diff --git a/docs/asciidoc/modules/ROOT/partials/generated-documentation/nav.adoc b/docs/asciidoc/modules/ROOT/partials/generated-documentation/nav.adoc
index e7553b4ed9..40296ead64 100644
--- a/docs/asciidoc/modules/ROOT/partials/generated-documentation/nav.adoc
+++ b/docs/asciidoc/modules/ROOT/partials/generated-documentation/nav.adoc
@@ -386,6 +386,7 @@ This file is generated by DocsTest, so don't change it!
 *** xref::overview/apoc.meta/apoc.meta.cypher.type.adoc[]
 *** xref::overview/apoc.meta/apoc.meta.cypher.types.adoc[]
 *** xref::overview/apoc.meta/apoc.meta.isType.adoc[]
+*** xref::overview/apoc.meta/apoc.meta.nodes.count.adoc[]
 *** xref::overview/apoc.meta/apoc.meta.type.adoc[]
 *** xref::overview/apoc.meta/apoc.meta.typeName.adoc[]
 *** xref::overview/apoc.meta/apoc.meta.types.adoc[]
diff --git a/docs/asciidoc/modules/ROOT/partials/usage/apoc.meta.nodes.count.adoc b/docs/asciidoc/modules/ROOT/partials/usage/apoc.meta.nodes.count.adoc
new file mode 100644
index 0000000000..967691f28f
--- /dev/null
+++ b/docs/asciidoc/modules/ROOT/partials/usage/apoc.meta.nodes.count.adoc
@@ -0,0 +1,66 @@
+The examples in this section are based on the following sample graph:
+
+[source,cypher]
+----
+CREATE (n:MyCountLabel {id: 1}), (:MyCountLabel {id: 2}), (m:ThirdLabel {id: 3})
+WITH n,m 
+CREATE (n)-[:MY_COUNT_REL]->(m), (n)-[:ANOTHER_MY_COUNT_REL]->(m), (n)<-[:ANOTHER_MY_COUNT_REL]-(m)
+----
+
+We can return all nodes with a label `MyCountLabel` or a label `ThirdLabel`
+
+[source,cypher]
+----
+RETURN apoc.meta.nodes.count(['MyCountLabel', 'ThirdLabel']) AS count;
+----
+
+.Results
+[opts="header"]
+|===
+| count                                                                                                                                                                                                                                | relationships
+| 3
+|===
+
+
+We can return all nodes with a label `MyCountLabel` and a relationship `MY_COUNT_REL` through the config param `rel`
+
+[source,cypher]
+----
+RETURN apoc.meta.nodes.count(['MyCountLabel'], {rels: ['MY_COUNT_REL']}) AS count;
+----
+
+.Results
+[opts="header"]
+|===
+| count                                                                                                                                                                                                                                | relationships
+| 1
+|===
+
+Moreover, we can return all nodes with a `outcome` relationship `MY_COUNT_REL` (with the suffix `>`):
+
+[source,cypher]
+----
+RETURN apoc.meta.nodes.count(['MyCountLabel'], {rels: ['MY_COUNT_REL>']}) AS count;
+----
+
+.Results
+[opts="header"]
+|===
+| count                                                                                                                                                                                                                                | relationships
+| 1
+|===
+
+otherwise with an `incoming` relationship `MY_COUNT_REL` (with the suffix `<`):
+
+[source,cypher]
+----
+RETURN apoc.meta.nodes.count(['MyCountLabel'], {rels: ['MY_COUNT_REL<']}) AS count;
+----
+
+.Results
+[opts="header"]
+|===
+| count                                                                                                                                                                                                                                | relationships
+| 0
+|===
+
diff --git a/docs/asciidoc/modules/ROOT/partials/usage/config/apoc.meta.nodes.count.adoc b/docs/asciidoc/modules/ROOT/partials/usage/config/apoc.meta.nodes.count.adoc
new file mode 100644
index 0000000000..775617ba61
--- /dev/null
+++ b/docs/asciidoc/modules/ROOT/partials/usage/config/apoc.meta.nodes.count.adoc
@@ -0,0 +1,9 @@
+The procedure support the following config parameters:
+
+.Config parameters
+[opts=header, cols="1,1,1,5"]
+|===
+| name | type | default | description
+| rels | Set<String> | `EmptySet` | The rel types to consider in the count. 
+    We can add to the suffix `>` or `<` to the rel type name to indicate an outgoing or incoming relationship.
+|===
\ No newline at end of file