SONAR-8467 Create WS api/project_analyses/search

1 files changed, 15 insertions, 0 deletions

diff --git a/sonar-core/src/main/java/org/sonar/core/util/stream/Collectors.java b/sonar-core/src/main/java/org/sonar/core/util/stream/Collectors.java
index 449261a6c4a..40990df3018 100644
--- a/sonar-core/src/main/java/org/sonar/core/util/stream/Collectors.java
+++ b/sonar-core/src/main/java/org/sonar/core/util/stream/Collectors.java
@@ -260,6 +260,21 @@ public final class Collectors {
       Collector.Characteristics.UNORDERED);
   }
 
+  /**
+   * For stream of one expected element, return the element
+   * @throws IllegalArgumentException if stream has no element or more than 1 element
+   */
+  public static <T> Collector<T, ?, T> toOneElement() {
+    return java.util.stream.Collectors.collectingAndThen(
+      java.util.stream.Collectors.toList(),
+      list -> {
+        if (list.size() != 1) {
+          throw new IllegalStateException("Stream should have only one element");
+        }
+        return list.get(0);
+      });
+  }
+
   private static <K, V> Supplier<Map<K, V>> newHashMapSupplier(int expectedSize) {
     return () -> expectedSize == DEFAULT_HASHMAP_CAPACITY ? new HashMap<>() : new HashMap<>(expectedSize);
   }