Added support for the map:keys Metapath function.

Author: david-waltermire

core/src/main/java/gov/nist/secauto/metaschema/core/metapath/function/library/DefaultFunctionLibrary.java

@@ -232,6 +232,8 @@ public DefaultFunctionLibrary() { // NOPMD - intentional
     registerFunction(MapMerge.SIGNATURE_TWO_ARG);
     // https://www.w3.org/TR/xpath-functions-31/#func-map-size
     registerFunction(MapSize.SIGNATURE);
+    // https://www.w3.org/TR/xpath-functions-31/#func-map-keys
+    registerFunction(MapKeys.SIGNATURE);
 
     // https://www.w3.org/TR/xpath-functions-31/#func-map-entry
     registerFunction(MapEntry.SIGNATURE);

core/src/main/java/gov/nist/secauto/metaschema/core/metapath/function/library/MapKeys.java

@@ -0,0 +1,92 @@
+/*
+ * Portions of this software was developed by employees of the National Institute
+ * of Standards and Technology (NIST), an agency of the Federal Government and is
+ * being made available as a public service. Pursuant to title 17 United States
+ * Code Section 105, works of NIST employees are not subject to copyright
+ * protection in the United States. This software may be subject to foreign
+ * copyright. Permission in the United States and in foreign countries, to the
+ * extent that NIST may hold copyright, to use, copy, modify, create derivative
+ * works, and distribute this software and its documentation without fee is hereby
+ * granted on a non-exclusive basis, provided that this notice and disclaimer
+ * of warranty appears in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
+ * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
+ * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
+ * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
+ * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE.  IN NO EVENT
+ * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
+ * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
+ * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
+ * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
+ * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
+ * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
+ */
+
+package gov.nist.secauto.metaschema.core.metapath.function.library;
+
+import gov.nist.secauto.metaschema.core.metapath.DynamicContext;
+import gov.nist.secauto.metaschema.core.metapath.ISequence;
+import gov.nist.secauto.metaschema.core.metapath.MetapathConstants;
+import gov.nist.secauto.metaschema.core.metapath.function.FunctionUtils;
+import gov.nist.secauto.metaschema.core.metapath.function.IArgument;
+import gov.nist.secauto.metaschema.core.metapath.function.IFunction;
+import gov.nist.secauto.metaschema.core.metapath.item.IItem;
+import gov.nist.secauto.metaschema.core.metapath.item.atomic.IAnyAtomicItem;
+import gov.nist.secauto.metaschema.core.metapath.item.function.IMapItem;
+import gov.nist.secauto.metaschema.core.metapath.item.function.IMapKey;
+import gov.nist.secauto.metaschema.core.util.ObjectUtils;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Stream;
+
+import edu.umd.cs.findbugs.annotations.NonNull;
+
+public class MapKeys {
+  @NonNull
+  static final IFunction SIGNATURE = IFunction.builder()
+      .name("keys")
+      .namespace(MetapathConstants.NS_METAPATH_FUNCTIONS_MAP)
+      .deterministic()
+      .contextIndependent()
+      .focusIndependent()
+      .argument(IArgument.builder()
+          .name("map")
+          .type(IMapItem.class)
+          .one()
+          .build())
+      .returnType(IAnyAtomicItem.class)
+      .returnZeroOrMore()
+      .functionHandler(MapKeys::execute)
+      .build();
+
+  /**
+   * An implementation of XPath 3.1 <a href=
+   * "https://www.w3.org/TR/xpath-functions-31/#func-map-size">map:size</a>.
+   *
+   * @param array
+   *          the arrays to join
+   * @return a new combined array
+   */
+  @SuppressWarnings("unused")
+  @NonNull
+  private static ISequence<IAnyAtomicItem> execute(@NonNull IFunction function,
+      @NonNull List<ISequence<?>> arguments,
+      @NonNull DynamicContext dynamicContext,
+      IItem focus) {
+    IMapItem<?> map = FunctionUtils.asType(ObjectUtils.requireNonNull(arguments.get(0).getFirstItem(true)));
+
+    return ISequence.of(keys(map));
+  }
+
+  public static Stream<IAnyAtomicItem> keys(@NonNull IMapItem<?> map) {
+    return keys((Map<IMapKey, ?>) map);
+  }
+
+  public static Stream<IAnyAtomicItem> keys(@NonNull Map<IMapKey, ?> map) {
+    return map.keySet().stream()
+        .map(IMapKey::getKey);
+  }
+}

core/src/test/java/gov/nist/secauto/metaschema/core/metapath/function/library/MapKeysTest.java

@@ -0,0 +1,55 @@
+/*
+ * Portions of this software was developed by employees of the National Institute
+ * of Standards and Technology (NIST), an agency of the Federal Government and is
+ * being made available as a public service. Pursuant to title 17 United States
+ * Code Section 105, works of NIST employees are not subject to copyright
+ * protection in the United States. This software may be subject to foreign
+ * copyright. Permission in the United States and in foreign countries, to the
+ * extent that NIST may hold copyright, to use, copy, modify, create derivative
+ * works, and distribute this software and its documentation without fee is hereby
+ * granted on a non-exclusive basis, provided that this notice and disclaimer
+ * of warranty appears in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
+ * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
+ * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
+ * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
+ * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE.  IN NO EVENT
+ * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
+ * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
+ * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
+ * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
+ * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
+ * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
+ */
+
+package gov.nist.secauto.metaschema.core.metapath.function.library;
+
+import static gov.nist.secauto.metaschema.core.metapath.TestUtils.integer;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import gov.nist.secauto.metaschema.core.metapath.ExpressionTestBase;
+import gov.nist.secauto.metaschema.core.metapath.ISequence;
+import gov.nist.secauto.metaschema.core.metapath.MetapathExpression;
+import gov.nist.secauto.metaschema.core.metapath.item.atomic.IAnyAtomicItem;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+class MapKeysTest
+    extends ExpressionTestBase {
+
+  @Test
+  void test() {
+    ISequence<IAnyAtomicItem> result = MetapathExpression.compile("map:keys(map{1:\"yes\", 2:\"no\"})")
+        .evaluateAs(null, MetapathExpression.ResultType.SEQUENCE);
+    // use a set to allow any ordering of the keys, since we have no control over
+    // their order
+    Set<IAnyAtomicItem> keys = new HashSet<>(result);
+
+    assertEquals(Set.of(integer(1), integer(2)), keys);
+  }
+}