[ISSUE-358] Implement ISO-GQL labeled predicate

geaflow/geaflow-dsl/geaflow-dsl-common/src/main/java/org/apache/geaflow/dsl/common/function/LabeledPredicateFunctions.java

@@ -0,0 +1,83 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.geaflow.dsl.common.function;
+
+import org.apache.geaflow.dsl.common.data.RowEdge;
+import org.apache.geaflow.dsl.common.data.RowVertex;
+
+/**
+ * Utility class providing static methods for the ISO-GQL labeled predicate.
+ *
+ * <p>Implements ISO-GQL Section 19.9: &lt;labeled predicate&gt;, which tests whether a
+ * graph element (vertex or edge) has a given label.
+ *
+ * <p>ISO-GQL General Rules (three-valued logic):
+ * <ul>
+ *   <li>If the element or the label is null, the result is Unknown (null).</li>
+ *   <li>If the element's label equals the given label, the result is True.</li>
+ *   <li>Otherwise, the result is False.</li>
+ * </ul>
+ */
+public class LabeledPredicateFunctions {
+
+    /**
+     * Implements the IS LABELED predicate.
+     *
+     * @param elementValue the vertex or edge to check
+     * @param labelValue the label name to test for
+     * @return Boolean: true if the element has the given label, false if not, null if either
+     *         operand is null
+     */
+    public static Boolean isLabeled(Object elementValue, Object labelValue) {
+        // ISO-GQL Rule: If element or label is null, result is Unknown (null).
+        if (elementValue == null || labelValue == null) {
+            return null;
+        }
+
+        String elementLabel = getLabel(elementValue);
+        return elementLabel != null && elementLabel.equals(labelValue.toString());
+    }
+
+    /**
+     * Implements the IS NOT LABELED predicate.
+     *
+     * @param elementValue the vertex or edge to check
+     * @param labelValue the label name to test for
+     * @return Boolean: true if the element does NOT have the given label, false if it does, null
+     *         if either operand is null
+     */
+    public static Boolean isNotLabeled(Object elementValue, Object labelValue) {
+        Boolean result = isLabeled(elementValue, labelValue);
+        // Three-valued logic: NOT Unknown = Unknown (null remains null).
+        return result == null ? null : !result;
+    }
+
+    private static String getLabel(Object elementValue) {
+        if (elementValue instanceof RowVertex) {
+            return ((RowVertex) elementValue).getLabel();
+        }
+        if (elementValue instanceof RowEdge) {
+            return ((RowEdge) elementValue).getLabel();
+        }
+        throw new IllegalArgumentException(
+            "First operand of labeled predicate must be a vertex or an edge, got: "
+                + elementValue.getClass().getName());
+    }
+}

geaflow/geaflow-dsl/geaflow-dsl-common/src/test/java/org/apache/geaflow/dsl/common/function/LabeledPredicateFunctionsTest.java

@@ -0,0 +1,74 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.geaflow.dsl.common.function;
+
+import org.apache.geaflow.dsl.common.data.RowEdge;
+import org.apache.geaflow.dsl.common.data.RowVertex;
+import org.apache.geaflow.dsl.common.data.impl.types.ObjectEdge;
+import org.apache.geaflow.dsl.common.data.impl.types.ObjectVertex;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+public class LabeledPredicateFunctionsTest {
+
+    private RowVertex vertex(String label) {
+        ObjectVertex vertex = new ObjectVertex(1L);
+        vertex.setLabel(label);
+        return vertex;
+    }
+
+    private RowEdge edge(String label) {
+        ObjectEdge edge = new ObjectEdge(1L, 2L);
+        edge.setLabel(label);
+        return edge;
+    }
+
+    @Test
+    public void testIsLabeledOnVertex() {
+        Assert.assertTrue(LabeledPredicateFunctions.isLabeled(vertex("person"), "person"));
+        Assert.assertFalse(LabeledPredicateFunctions.isLabeled(vertex("person"), "software"));
+    }
+
+    @Test
+    public void testIsLabeledOnEdge() {
+        Assert.assertTrue(LabeledPredicateFunctions.isLabeled(edge("knows"), "knows"));
+        Assert.assertFalse(LabeledPredicateFunctions.isLabeled(edge("knows"), "created"));
+    }
+
+    @Test
+    public void testIsNotLabeled() {
+        Assert.assertFalse(LabeledPredicateFunctions.isNotLabeled(vertex("person"), "person"));
+        Assert.assertTrue(LabeledPredicateFunctions.isNotLabeled(vertex("person"), "software"));
+    }
+
+    @Test
+    public void testThreeValuedLogicWithNullOperand() {
+        // Null element or null label yields Unknown (null) for both predicates.
+        Assert.assertNull(LabeledPredicateFunctions.isLabeled(null, "person"));
+        Assert.assertNull(LabeledPredicateFunctions.isLabeled(vertex("person"), null));
+        Assert.assertNull(LabeledPredicateFunctions.isNotLabeled(null, "person"));
+        Assert.assertNull(LabeledPredicateFunctions.isNotLabeled(vertex("person"), null));
+    }
+
+    @Test(expectedExceptions = IllegalArgumentException.class)
+    public void testNonGraphElementIsRejected() {
+        LabeledPredicateFunctions.isLabeled("not a graph element", "person");
+    }
+}

geaflow/geaflow-dsl/geaflow-dsl-plan/src/main/java/org/apache/geaflow/dsl/schema/function/BuildInSqlFunctionTable.java

@@ -97,7 +97,9 @@
 import org.apache.geaflow.dsl.udf.table.other.If;
 import org.apache.geaflow.dsl.udf.table.other.IsDecimal;
 import org.apache.geaflow.dsl.udf.table.other.IsDestinationOf;
+import org.apache.geaflow.dsl.udf.table.other.IsLabeled;
 import org.apache.geaflow.dsl.udf.table.other.IsNotDestinationOf;
+import org.apache.geaflow.dsl.udf.table.other.IsNotLabeled;
 import org.apache.geaflow.dsl.udf.table.other.IsNotSourceOf;
 import org.apache.geaflow.dsl.udf.table.other.IsSourceOf;
 import org.apache.geaflow.dsl.udf.table.other.Label;
@@ -226,6 +228,9 @@ public class BuildInSqlFunctionTable extends ListSqlOperatorTable {
             .add(GeaFlowFunction.of(IsNotSourceOf.class))
             .add(GeaFlowFunction.of(IsDestinationOf.class))
             .add(GeaFlowFunction.of(IsNotDestinationOf.class))
+            // ISO-GQL labeled predicate
+            .add(GeaFlowFunction.of(IsLabeled.class))
+            .add(GeaFlowFunction.of(IsNotLabeled.class))
             // ISO-GQL property exists predicate
             .add(GeaFlowFunction.of(PropertyExists.class))
             // UDAF

geaflow/geaflow-dsl/geaflow-dsl-plan/src/main/java/org/apache/geaflow/dsl/udf/table/other/IsLabeled.java

@@ -0,0 +1,81 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.geaflow.dsl.udf.table.other;
+
+import org.apache.geaflow.dsl.common.data.RowEdge;
+import org.apache.geaflow.dsl.common.data.RowVertex;
+import org.apache.geaflow.dsl.common.function.Description;
+import org.apache.geaflow.dsl.common.function.LabeledPredicateFunctions;
+import org.apache.geaflow.dsl.common.function.UDF;
+
+/**
+ * UDF implementation for the ISO-GQL IS LABELED predicate.
+ *
+ * <p>Implements ISO-GQL Section 19.9: &lt;labeled predicate&gt;
+ *
+ * <p><b>Syntax:</b></p>
+ * <pre>
+ *   IS_LABELED(element, label)
+ * </pre>
+ *
+ * <p><b>Semantics:</b></p>
+ * Returns TRUE if the vertex or edge has the given label, FALSE if not, or NULL if either
+ * operand is NULL.
+ *
+ * <p><b>Example:</b></p>
+ * <pre>
+ * MATCH (a) -[e]-> (b)
+ * WHERE IS_LABELED(a, 'person')
+ * RETURN a, e, b
+ * </pre>
+ */
+@Description(
+    name = "is_labeled",
+    description = "ISO-GQL Labeled Predicate: Returns TRUE if the vertex or edge has the given "
+        + "label, FALSE if not, NULL if either operand is NULL. Follows ISO-GQL three-valued logic."
+)
+public class IsLabeled extends UDF {
+
+    /**
+     * Evaluates the IS LABELED predicate.
+     *
+     * @param elementValue vertex or edge to check
+     * @param labelValue label name to test for
+     * @return Boolean: true if the element has the given label, false if not, null if either
+     *         operand is null
+     */
+    public Boolean eval(Object elementValue, Object labelValue) {
+        return LabeledPredicateFunctions.isLabeled(elementValue, labelValue);
+    }
+
+    /**
+     * Type-specific overload for vertices.
+     */
+    public Boolean eval(RowVertex vertex, String label) {
+        return LabeledPredicateFunctions.isLabeled(vertex, label);
+    }
+
+    /**
+     * Type-specific overload for edges.
+     */
+    public Boolean eval(RowEdge edge, String label) {
+        return LabeledPredicateFunctions.isLabeled(edge, label);
+    }
+}

geaflow/geaflow-dsl/geaflow-dsl-plan/src/main/java/org/apache/geaflow/dsl/udf/table/other/IsNotLabeled.java

@@ -0,0 +1,82 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.geaflow.dsl.udf.table.other;
+
+import org.apache.geaflow.dsl.common.data.RowEdge;
+import org.apache.geaflow.dsl.common.data.RowVertex;
+import org.apache.geaflow.dsl.common.function.Description;
+import org.apache.geaflow.dsl.common.function.LabeledPredicateFunctions;
+import org.apache.geaflow.dsl.common.function.UDF;
+
+/**
+ * UDF implementation for the ISO-GQL IS NOT LABELED predicate.
+ *
+ * <p>Implements ISO-GQL Section 19.9: &lt;labeled predicate&gt;
+ *
+ * <p><b>Syntax:</b></p>
+ * <pre>
+ *   IS_NOT_LABELED(element, label)
+ * </pre>
+ *
+ * <p><b>Semantics:</b></p>
+ * Returns TRUE if the vertex or edge does NOT have the given label, FALSE if it does, or NULL
+ * if either operand is NULL.
+ *
+ * <p><b>Example:</b></p>
+ * <pre>
+ * MATCH (a) -[e]-> (b)
+ * WHERE IS_NOT_LABELED(a, 'software')
+ * RETURN a, e, b
+ * </pre>
+ */
+@Description(
+    name = "is_not_labeled",
+    description = "ISO-GQL Labeled Predicate: Returns TRUE if the vertex or edge does NOT have "
+        + "the given label, FALSE if it does, NULL if either operand is NULL. Follows ISO-GQL "
+        + "three-valued logic."
+)
+public class IsNotLabeled extends UDF {
+
+    /**
+     * Evaluates the IS NOT LABELED predicate.
+     *
+     * @param elementValue vertex or edge to check
+     * @param labelValue label name to test for
+     * @return Boolean: true if the element does NOT have the given label, false if it does, null
+     *         if either operand is null
+     */
+    public Boolean eval(Object elementValue, Object labelValue) {
+        return LabeledPredicateFunctions.isNotLabeled(elementValue, labelValue);
+    }
+
+    /**
+     * Type-specific overload for vertices.
+     */
+    public Boolean eval(RowVertex vertex, String label) {
+        return LabeledPredicateFunctions.isNotLabeled(vertex, label);
+    }
+
+    /**
+     * Type-specific overload for edges.
+     */
+    public Boolean eval(RowEdge edge, String label) {
+        return LabeledPredicateFunctions.isNotLabeled(edge, label);
+    }
+}

geaflow/geaflow-dsl/geaflow-dsl-runtime/src/test/java/org/apache/geaflow/dsl/runtime/query/GQLLabeledPredicateTest.java

@@ -0,0 +1,35 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.geaflow.dsl.runtime.query;
+
+import org.testng.annotations.Test;
+
+public class GQLLabeledPredicateTest {
+
+    @Test
+    public void testLabeledPredicate_001() throws Exception {
+        QueryTester
+            .build()
+            .withGraphDefine("/query/modern_graph.sql")
+            .withQueryPath("/query/gql_labeled_predicate_001.sql")
+            .execute()
+            .checkSinkResult();
+    }
+}

geaflow/geaflow-dsl/geaflow-dsl-runtime/src/test/resources/expect/gql_labeled_predicate_001.txt

@@ -0,0 +1,6 @@
+1,2,true,false,true,false
+1,3,true,true,true,true
+1,4,true,false,true,false
+4,3,true,true,true,true
+4,5,true,true,true,true
+6,3,true,true,true,true