Support variables in Filter Rows values

plugins/transforms/filterrows/src/main/java/org/apache/hop/pipeline/transforms/filterrows/FilterRows.java

@@ -18,6 +18,7 @@
 package org.apache.hop.pipeline.transforms.filterrows;
 
 import java.util.List;
+import org.apache.hop.core.Condition;
 import org.apache.hop.core.Const;
 import org.apache.hop.core.exception.HopException;
 import org.apache.hop.core.row.IRowMeta;
@@ -47,7 +48,7 @@ public FilterRows(
 
   private synchronized boolean keepRow(IRowMeta rowMeta, Object[] row) throws HopException {
     try {
-      return meta.getCondition().evaluate(rowMeta, row);
+      return data.condition.evaluate(rowMeta, row);
     } catch (Exception e) {
       String message =
           BaseMessages.getString(
@@ -160,9 +161,9 @@ public boolean processRow() throws HopException {
   public boolean init() {
 
     if (super.init()) {
-      // could it be a better idea to have a clone on the condition in data and do this on the first
-      // row?
-      meta.getCondition().clearFieldPositions();
+      data.condition = meta.getCondition().clone();
+      resolveVariables(data.condition);
+      data.condition.clearFieldPositions();
 
       List<IStream> targetStreams = meta.getTransformIOMeta().getTargetStreams();
       data.trueTransformName = targetStreams.get(0).getTransformName();
@@ -176,6 +177,19 @@ public boolean init() {
     return false;
   }
 
+  void resolveVariables(Condition condition) {
+    if (condition.isAtomic()) {
+      Condition.CValue rightValue = condition.getRightValue();
+      if (rightValue != null && rightValue.getText() != null) {
+        rightValue.setText(resolve(rightValue.getText()));
+      }
+    } else {
+      for (int i = 0; i < condition.nrConditions(); i++) {
+        resolveVariables(condition.getCondition(i));
+      }
+    }
+  }
+
   protected void checkNonExistingFields() throws HopException {
     List<String> orphanFields = meta.getOrphanFields(meta.getCondition(), getInputRowMeta());
     if (!Utils.isEmpty(orphanFields)) {

plugins/transforms/filterrows/src/main/java/org/apache/hop/pipeline/transforms/filterrows/FilterRowsData.java

@@ -17,6 +17,7 @@
 
 package org.apache.hop.pipeline.transforms.filterrows;
 
+import org.apache.hop.core.Condition;
 import org.apache.hop.core.IRowSet;
 import org.apache.hop.core.row.IRowMeta;
 import org.apache.hop.pipeline.transform.BaseTransformData;
@@ -31,6 +32,7 @@ public class FilterRowsData extends BaseTransformData implements ITransformData
   public boolean chosesTargetTransforms;
   public String trueTransformName;
   public String falseTransformName;
+  public Condition condition;
 
   public FilterRowsData() {
     super();

plugins/transforms/filterrows/src/main/java/org/apache/hop/pipeline/transforms/filterrows/FilterRowsDialog.java

@@ -151,7 +151,7 @@ public String open() {
           ke);
     }
 
-    wCondition = new ConditionEditor(shell, SWT.BORDER, condition, inputfields);
+    wCondition = new ConditionEditor(shell, SWT.BORDER, condition, inputfields, variables);
 
     FormData fdCondition = new FormData();
     fdCondition.left = new FormAttachment(0, 0);

plugins/transforms/filterrows/src/test/java/org/apache/hop/pipeline/transforms/filterrows/FilterRowsTest.java

@@ -0,0 +1,154 @@
+/*
+ * 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.hop.pipeline.transforms.filterrows;
+
+import static org.apache.hop.core.Condition.Function.EQUAL;
+import static org.apache.hop.core.Condition.Function.REGEXP;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.math.BigDecimal;
+import java.sql.Timestamp;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.stream.Stream;
+import org.apache.hop.core.Condition;
+import org.apache.hop.core.HopEnvironment;
+import org.apache.hop.core.row.IValueMeta;
+import org.apache.hop.core.row.RowMeta;
+import org.apache.hop.core.row.ValueMetaAndData;
+import org.apache.hop.core.row.value.ValueMetaBigNumber;
+import org.apache.hop.core.row.value.ValueMetaBoolean;
+import org.apache.hop.core.row.value.ValueMetaDate;
+import org.apache.hop.core.row.value.ValueMetaInteger;
+import org.apache.hop.core.row.value.ValueMetaNumber;
+import org.apache.hop.core.row.value.ValueMetaString;
+import org.apache.hop.core.row.value.ValueMetaTimestamp;
+import org.apache.hop.pipeline.PipelineMeta;
+import org.apache.hop.pipeline.engines.local.LocalPipelineEngine;
+import org.apache.hop.pipeline.transform.TransformMeta;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class FilterRowsTest {
+
+  @BeforeAll
+  static void setUp() throws Exception {
+    HopEnvironment.init();
+  }
+
+  @ParameterizedTest(name = "{0}")
+  @MethodSource("variableValueTypes")
+  void resolvesAndConvertsVariableForSupportedScalarTypes(
+      String type,
+      IValueMeta valueMeta,
+      Object matchingValue,
+      Object differentValue,
+      String variable)
+      throws Exception {
+    Condition.CValue constant =
+        new Condition.CValue(new ValueMetaAndData(valueMeta, matchingValue));
+    constant.setText("${FILTER_VALUE}");
+    Condition metadataCondition = new Condition();
+    metadataCondition.setLeftValueName("value");
+    metadataCondition.setFunction(EQUAL);
+    metadataCondition.setRightValue(constant);
+
+    FilterRows transform = createTransform(metadataCondition);
+    transform.setVariable("FILTER_VALUE", variable);
+    Condition runtimeCondition = metadataCondition.clone();
+    transform.resolveVariables(runtimeCondition);
+
+    RowMeta rowMeta = new RowMeta();
+    rowMeta.addValueMeta(valueMeta.clone());
+    assertEquals(variable, runtimeCondition.getRightValueString());
+    assertEquals("${FILTER_VALUE}", metadataCondition.getRightValueString());
+    assertTrue(runtimeCondition.evaluate(rowMeta, new Object[] {matchingValue}));
+    assertFalse(runtimeCondition.evaluate(rowMeta, new Object[] {differentValue}));
+  }
+
+  @Test
+  void resolvesVariablesInNestedConditionValuesWithoutChangingMetadata() throws Exception {
+    Condition stringCondition =
+        new Condition("name", EQUAL, null, new ValueMetaAndData("constant", "${NAME}"));
+    Condition regexCondition =
+        new Condition("code", REGEXP, null, new ValueMetaAndData("constant", "${CODE_REGEX}"));
+    Condition condition = new Condition();
+    condition.addCondition(stringCondition);
+    condition.addCondition(regexCondition);
+
+    FilterRows transform = createTransform(condition);
+    transform.setVariable("NAME", "Alice");
+    transform.setVariable("CODE_REGEX", "A-[0-9]+");
+
+    Condition runtimeCondition = condition.clone();
+    transform.resolveVariables(runtimeCondition);
+
+    assertEquals("Alice", runtimeCondition.getCondition(0).getRightValueString());
+    assertEquals("A-[0-9]+", runtimeCondition.getCondition(1).getRightValueString());
+    assertEquals("${NAME}", condition.getCondition(0).getRightValueString());
+    assertEquals("${CODE_REGEX}", condition.getCondition(1).getRightValueString());
+
+    RowMeta rowMeta = new RowMeta();
+    rowMeta.addValueMeta(new ValueMetaString("name"));
+    rowMeta.addValueMeta(new ValueMetaString("code"));
+    assertTrue(runtimeCondition.evaluate(rowMeta, new Object[] {"Alice", "A-123"}));
+    assertFalse(runtimeCondition.evaluate(rowMeta, new Object[] {"Alice", "B-123"}));
+  }
+
+  private static Stream<Arguments> variableValueTypes() throws Exception {
+    ValueMetaDate dateMeta = new ValueMetaDate("value");
+    dateMeta.setConversionMask("yyyy-MM-dd");
+    Date date = new SimpleDateFormat("yyyy-MM-dd").parse("2026-07-29");
+    Date otherDate = new SimpleDateFormat("yyyy-MM-dd").parse("2026-07-30");
+
+    ValueMetaTimestamp timestampMeta = new ValueMetaTimestamp("value");
+    timestampMeta.setConversionMask("yyyy-MM-dd HH:mm:ss.SSS");
+    Timestamp timestamp = Timestamp.valueOf("2026-07-29 12:34:56.789");
+    Timestamp otherTimestamp = Timestamp.valueOf("2026-07-29 12:34:57.789");
+
+    return Stream.of(
+        Arguments.of("String", new ValueMetaString("value"), "Alice", "Bob", "Alice"),
+        Arguments.of("Integer", new ValueMetaInteger("value"), 42L, 43L, "42"),
+        Arguments.of("Number", new ValueMetaNumber("value"), 12.5D, 13.5D, "12.5"),
+        Arguments.of(
+            "BigNumber",
+            new ValueMetaBigNumber("value"),
+            new BigDecimal("123456789.0123"),
+            new BigDecimal("123456789.0124"),
+            "123456789.0123"),
+        Arguments.of("Boolean", new ValueMetaBoolean("value"), true, false, "Y"),
+        Arguments.of("Date", dateMeta, date, otherDate, "2026-07-29"),
+        Arguments.of(
+            "Timestamp", timestampMeta, timestamp, otherTimestamp, "2026-07-29 12:34:56.789"));
+  }
+
+  private static FilterRows createTransform(Condition condition) {
+    FilterRowsMeta meta = new FilterRowsMeta();
+    meta.setCondition(condition);
+    TransformMeta transformMeta = new TransformMeta("Filter rows", meta);
+    PipelineMeta pipelineMeta = new PipelineMeta();
+    pipelineMeta.addTransform(transformMeta);
+    return new FilterRows(
+        transformMeta, meta, new FilterRowsData(), 0, pipelineMeta, new LocalPipelineEngine());
+  }
+}