Data commit

Task/Hash-join/Groovy/hash-join-1.groovy

@@ -0,0 +1,15 @@
+def hashJoin(table1, col1, table2, col2) {
+
+    def hashed = table1.groupBy { s -> s[col1] }
+
+    def q = [] as Set
+
+    table2.each { r ->
+        def join = hashed[r[col2]]
+        join.each { s ->
+            q << s.plus(r)
+        }
+    }
+
+    q
+}

Task/Hash-join/Groovy/hash-join-2.groovy

@@ -0,0 +1,8 @@
+def hashJoin(table1, col1, table2, col2) {
+
+    def hashed = table1.groupBy { s -> s[col1] }
+
+    table2.collect { r ->
+        hashed[r[col2]].collect { s -> s.plus(r) }
+    }.flatten()
+}

Task/Hash-join/Groovy/hash-join-3.groovy

@@ -0,0 +1,13 @@
+def s = [[age: 27, name: 'Jonah'],
+         [age: 18, name: 'Alan'],
+         [age: 28, name: 'Glory'],
+         [age: 18, name: 'Popeye'],
+         [age: 28, name: 'Alan']]
+
+def r = [[name: 'Jonah', nemesis: 'Whales'],
+         [name: 'Jonah', nemesis: 'Spiders'],
+         [name: 'Alan', nemesis: 'Ghosts'],
+         [name: 'Alan', nemesis: 'Zombies'],
+         [name: 'Glory', nemesis: 'Buffy']]
+
+hashJoin(s, "name", r, "name").sort {it.name}.each { println it }