Added conversions for fj.data to standard java.util classes

mperry · mperry · commit fedea6bf31df · 2016-02-14T14:07:26.000+10:00
diff --git a/core/src/main/java/fj/data/Array.java b/core/src/main/java/fj/data/Array.java
@@ -127,6 +127,10 @@ public Object[] array() {
     return copyOf(a, a.length);
   }
 
+  public A[] toJavaArray() {
+    return (A[]) array();
+  }
+
   /**
    * Returns an option projection of this array; <code>None</code> if empty, or the first element in
    * <code>Some</code>.
@@ -795,6 +799,13 @@ public int size() {
     };
   }
 
+  /**
+   * Returns a standard java.util.List projection of this array.
+   */
+  java.util.List<A> toJavaList() {
+    return new ArrayList<A>(toCollection());
+  }
+
   /**
    * Takes the given iterable to an array.
    *
diff --git a/core/src/main/java/fj/data/DList.java b/core/src/main/java/fj/data/DList.java
@@ -71,6 +71,13 @@ public static <A> DList<A> arrayDList(final A...as) {
     public List<A> run() {
         return appendFn.f(List.<A>nil()).run();
     }
+
+    /**
+     * Converts the DList to a standard java.util.List.
+     */
+    public java.util.List toJavaList() {
+        return run().toJavaList();
+    }
     
     /**
      * A empty DList.
diff --git a/core/src/main/java/fj/data/HashMap.java b/core/src/main/java/fj/data/HashMap.java
@@ -5,6 +5,7 @@
 
 import java.util.Collection;
 import java.util.Iterator;
+import java.util.Map;
 
 import static fj.P.p;
 import static fj.data.Option.fromNull;
@@ -341,6 +342,18 @@ public static <K, V> HashMap<K, V> from(final Iterable<P2<K, V>> entries) {
     return iterableHashMap(Equal.<K>anyEqual(), Hash.<K>anyHash(), entries);
   }
 
+  public static <K, V> HashMap<K, V> fromMap(java.util.Map<K, V> map) {
+    return fromMap(Equal.anyEqual(), Hash.anyHash(), map);
+  }
+
+  public static <K, V> HashMap<K, V> fromMap(Equal<K> eq, Hash<K> h, java.util.Map<K, V> map) {
+    HashMap<K, V> m = HashMap.hashMap(eq, h);
+    for (Map.Entry<K, V> e: map.entrySet()) {
+      m.set(e.getKey(), e.getValue());
+    }
+    return m;
+  }
+
   /**
    * Converts the Iterable to a HashMap
    *
diff --git a/core/src/main/java/fj/data/HashSet.java b/core/src/main/java/fj/data/HashSet.java
@@ -225,6 +225,18 @@ public List<A> toList() {
     return m.keys();
   }
 
+  public java.util.List<A> toJavaList() {
+    return toList().toJavaList();
+  }
+
+  public java.util.Set<A> toJavaSet() {
+    return new java.util.HashSet<A>(toCollection());
+  }
+
+  public static <A> HashSet<A> fromSet(java.util.Set<A> s) {
+    return iterableHashSet(s);
+  }
+
   /**
    * Projects an immutable collection of this hash set.
    *
diff --git a/core/src/main/java/fj/data/List.java b/core/src/main/java/fj/data/List.java
@@ -197,15 +197,22 @@ public final Stream<A> toStream() {
    */
   @SuppressWarnings({"unchecked"})
   public final Array<A> toArray() {
+    return mkArray(toArrayObject());
+  }
+
+  public final Object[] toArrayObject() {
     final int length = length();
     final Object[] a = new Object[length];
     List<A> x = this;
     for (int i = 0; i < length; i++) {
       a[i] = x.head();
       x = x.tail();
     }
+    return a;
+  }
 
-    return mkArray(a);
+  public final A[] toJavaArray() {
+    return (A[]) toArrayObject();
   }
 
   /**
diff --git a/core/src/main/java/fj/data/Stream.java b/core/src/main/java/fj/data/Stream.java
@@ -916,6 +916,17 @@ public final Option<A> toOption() {
     return isEmpty() ? Option.<A>none() : some(head());
   }
 
+  @SuppressWarnings({"unchecked", "UnnecessaryFullyQualifiedName"})
+  public final A[] toJavaArray() {
+    final A[] array = (A[]) new Object[length()];
+    int i = 0;
+    for (A a: this) {
+      array[i] = a;
+      i++;
+    }
+    return array;
+  }
+
   /**
    * Returns a list projection of this stream.
    *
diff --git a/core/src/test/java/fj/data/ArrayTest.java b/core/src/test/java/fj/data/ArrayTest.java
@@ -0,0 +1,13 @@
+package fj.data;
+
+/**
+ * Created by MarkPerry on 14 Feb 16.
+ */
+public class ArrayTest {
+
+
+    public void test1() {
+
+    }
+
+}
diff --git a/core/src/test/java/fj/data/ListTest.java b/core/src/test/java/fj/data/ListTest.java
@@ -81,4 +81,14 @@ public void listReduce() {
         assertThat(expected, equalTo(list));
     }
 
+    @Test
+    public void toJavaArray() {
+        final int max = 3;
+        Integer[] ints = new Integer[max];
+        for (int i = 0; i < max; i++) {
+            ints[i] = i + 1;
+        };
+        assertThat(List.range(1, max + 1).toJavaArray(), equalTo(ints));
+    }
+
 }

Original file line number	Diff line number	Diff line change
`@@ -81,4 +81,14 @@ public void listReduce() {`
`81`	`81`	`assertThat(expected, equalTo(list));`
`82`	`82`	`}`
`83`	`83`
	`84`	`+ @Test`
	`85`	`+ public void toJavaArray() {`
	`86`	`+ final int max = 3;`
	`87`	`+ Integer[] ints = new Integer[max];`
	`88`	`+ for (int i = 0; i < max; i++) {`
	`89`	`+ ints[i] = i + 1;`
	`90`	`+ };`
	`91`	`+ assertThat(List.range(1, max + 1).toJavaArray(), equalTo(ints));`
	`92`	`+ }`
	`93`	`+`
`84`	`94`	`}`