Common utility classes developed as part of refactor for RM-2549.

asSet method that works like java.util.Arrays.asList.
  Also variants of java.util.Arrays.asList that take Supplier<T> rather than T.


git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/modules/recordsmanagement/BRANCHES/classified_renditions@111287 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

rm-server/unit-test/java/org/alfresco/module/org_alfresco_module_rm/test/util/FPUtils.java

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+/*
+ * Copyright (C) 2005-2015 Alfresco Software Limited.
+ *
+ * This file is part of Alfresco
+ *
+ * Alfresco is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.alfresco.module.org_alfresco_module_rm.test.util;
+
+import static java.util.stream.Collectors.toList;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.function.Supplier;
+import java.util.stream.Stream;
+
+/**
+ * Utility class to help with Java 8 FP stuff.
+ *
+ * @author Neil Mc Erlean
+ * @since 3.0.a
+ */
+public class FPUtils
+{
+    /**
+     * This method is intended to work exactly like {@code java.util.Arrays.asList()} but it takes
+     * a vararg of {@code Supplier}s instead of actual objects.
+     *
+     * @param suppliers a vararg of {@link Supplier}s giving a sequence of values for the list.
+     * @param <T> the type of elements in the list.
+     * @return the list with each element retrieved from a {@code Supplier}.
+     */
+    public static <T> List<T> asListFrom(Supplier<T>... suppliers)
+    {
+        if (suppliers == null || suppliers.length == 0)
+        {
+            return Collections.emptyList();
+        }
+        else
+        {
+            return Stream.of(suppliers)
+                         .map(s -> s.get())
+                         .collect(toList());
+        }
+    }
+
+    public static <T> Set<T> asSetFrom(Supplier<T>... suppliers)
+    {
+        List<T> l = asListFrom(suppliers);
+        Set<T> result = new HashSet<>();
+        result.addAll(l);
+        return result;
+    }
+
+    /**
+     * This utility method converts a vararg of objects into a Set<T>.
+     *
+     * @param objects the objects to be added to the set
+     * @return a Set of objects (any equal objects will of course not be duplicated)
+     */
+    public static <T> Set<T> asSet(T... objects)
+    {
+        Set<T> result = new HashSet<>();
+        for (T obj : objects)
+        {
+            result.add(obj);
+        }
+
+        return result;
+    }
+}

rm-server/unit-test/java/org/alfresco/module/org_alfresco_module_rm/test/util/FPUtilsUnitTest.java

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+/*
+ * Copyright (C) 2005-2015 Alfresco Software Limited.
+ *
+ * This file is part of Alfresco
+ *
+ * Alfresco is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.alfresco.module.org_alfresco_module_rm.test.util;
+
+import static org.alfresco.module.org_alfresco_module_rm.test.util.FPUtils.asListFrom;
+import static org.alfresco.module.org_alfresco_module_rm.test.util.FPUtils.asSet;
+import static org.junit.Assert.assertEquals;
+import static java.util.Arrays.asList;
+import static java.util.Collections.emptyList;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.junit.Test;
+
+/**
+ * Unit tests for {@link FPUtils}.
+ *
+ * @author Neil Mc Erlean
+ * @since 3.0.a
+ */
+public class FPUtilsUnitTest
+{
+    @Test public void asListShouldProduceList()
+    {
+        List<String> l = asListFrom(() -> "hello",
+                                    () -> "world",
+                                    () -> {
+                                        String s1 = "abc";
+                                        String s2 = "xyz";
+                                        return s1 + s2;
+                                    });
+        assertEquals(asList("hello", "world", "abcxyz"), l);
+    }
+
+    @Test public void asListShouldWorkForEmptyVarArgs()
+    {
+        assertEquals(emptyList(), FPUtils.<String>asListFrom());
+    }
+
+    @Test public void asSetShouldProduceSet()
+    {
+        Set<String> expectedSet = new HashSet<>();
+        expectedSet.add("hello");
+        expectedSet.add("world");
+
+        assertEquals(expectedSet, asSet("hello", "hello", "world"));
+    }
+}