new: CQuery#join

assira.core/src/main/java/net/ranides/assira/collection/query/CQuery.java

@@ -64,6 +64,10 @@ public interface CQuery<T> extends Iterable<T> {
     
     Set<T> set();
 
+    String join();
+
+    String join(String joiner);
+
     CQuery<T> fetch();
 
     CQuery<T> prefetch();

assira.core/src/main/java/net/ranides/assira/collection/query/CQueryAbstract.java

@@ -66,6 +66,16 @@ public abstract class CQueryAbstract<T> implements CQuery<T> {
         return stream().collect(Collectors.toSet());
     }
 
+    @Override
+    public String join() {
+        return map(String::valueOf).collect(Collectors.joining());
+    }
+
+    @Override
+    public String join(String joiner) {
+        return map(String::valueOf).collect(Collectors.joining(joiner));
+    }
+
     @Override
     public CQuery<T> append(CQuery<T> next) {
         return new CQMerge<>(this, next);