Load default loadflow parameters from json file in classpath (#3040)

* Add default loadflow parameters loader from json in resources
* Add abstract class
* Fix dummy extension class

Signed-off-by: Hugo KULESZA <hugo.kulesza@rte-france.com>

loadflow/loadflow-api/src/main/java/com/powsybl/loadflow/AbstractLoadFlowDefaultParametersLoader.java

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) 2024, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+package com.powsybl.loadflow;
+
+import java.io.InputStream;
+import java.util.Objects;
+
+/**
+ * @author Hugo Kulesza {@literal <hugo.kulesza at rte-france.com>}
+ */
+public abstract class AbstractLoadFlowDefaultParametersLoader implements LoadFlowDefaultParametersLoader {
+
+    private final String name;
+    private final String jsonParametersFile;
+
+    AbstractLoadFlowDefaultParametersLoader(String name, String jsonParametersFile) {
+        this.name = Objects.requireNonNull(name);
+        this.jsonParametersFile = Objects.requireNonNull(jsonParametersFile);
+    }
+
+    @Override
+    public String getSourceName() {
+        return name;
+    }
+
+    public InputStream loadDefaultParametersFromFile() {
+        return getClass().getResourceAsStream(jsonParametersFile);
+    }
+}

loadflow/loadflow-api/src/main/java/com/powsybl/loadflow/LoadFlowDefaultParametersLoader.java

@@ -0,0 +1,20 @@
+/**
+ * Copyright (c) 2024, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+package com.powsybl.loadflow;
+
+import java.io.InputStream;
+
+/**
+ * @author Hugo Kulesza {@literal <hugo.kulesza at rte-france.com>}
+ */
+public interface LoadFlowDefaultParametersLoader {
+
+    String getSourceName();
+
+    InputStream loadDefaultParametersFromFile();
+}

loadflow/loadflow-api/src/main/java/com/powsybl/loadflow/LoadFlowParameters.java

@@ -14,6 +14,8 @@
 import com.powsybl.commons.util.ServiceLoaderCache;
 import com.powsybl.iidm.network.Country;
 import com.powsybl.loadflow.json.JsonLoadFlowParameters;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
@@ -69,6 +71,8 @@ public enum ConnectedComponentMode {
         ALL,
     }
 
+    public static final Logger LOGGER = LoggerFactory.getLogger(LoadFlowParameters.class);
+
     // VERSION = 1.0 specificCompatibility
     // VERSION = 1.1 t2wtSplitShuntAdmittance
     // VERSION = 1.2 twtSplitShuntAdmittance,
@@ -182,6 +186,25 @@ protected static void load(LoadFlowParameters parameters, PlatformConfig platfor
     private double dcPowerFactor = DEFAULT_DC_POWER_FACTOR;
 
     public LoadFlowParameters() {
+        this(ServiceLoader.load(LoadFlowDefaultParametersLoader.class)
+                .stream()
+                .map(ServiceLoader.Provider::get)
+                .toList());
+    }
+
+    public LoadFlowParameters(List<LoadFlowDefaultParametersLoader> defaultParametersLoaders) {
+        int numberOfLoadersFound = Objects.requireNonNull(defaultParametersLoaders).size();
+        if (numberOfLoadersFound > 1) {
+            List<String> names = defaultParametersLoaders.stream()
+                    .map(LoadFlowDefaultParametersLoader::getSourceName)
+                    .toList();
+            LOGGER.warn("Multiple default loadflow parameters classes have been found in the class path : {}. No default parameters file loaded",
+                    names);
+        } else if (numberOfLoadersFound == 1) {
+            LoadFlowDefaultParametersLoader loader = defaultParametersLoaders.get(0);
+            JsonLoadFlowParameters.update(this, loader.loadDefaultParametersFromFile());
+            LOGGER.debug("Default loadflow configuration has been updated using the reference file from parameters loader '{}'", loader.getSourceName());
+        }
     }
 
     protected LoadFlowParameters(LoadFlowParameters other) {

loadflow/loadflow-api/src/test/java/com/powsybl/loadflow/LoadFlowDefaultParametersLoaderMock.java

@@ -0,0 +1,20 @@
+/**
+ * Copyright (c) 2024, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+package com.powsybl.loadflow;
+
+/**
+ * @author Hugo Kulesza {@literal <hugo.kulesza at rte-france.com>}
+ */
+public class LoadFlowDefaultParametersLoaderMock extends AbstractLoadFlowDefaultParametersLoader {
+
+    private static final String RESOURCE_FILE = "/LoadFlowParametersUpdate.json";
+
+    LoadFlowDefaultParametersLoaderMock(String name) {
+        super(name, RESOURCE_FILE);
+    }
+}

loadflow/loadflow-api/src/test/java/com/powsybl/loadflow/LoadFlowDefaultParametersLoaderTest.java

@@ -0,0 +1,44 @@
+/**
+ * Copyright (c) 2024, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+package com.powsybl.loadflow;
+
+import com.powsybl.commons.extensions.Extension;
+import com.powsybl.loadflow.json.JsonLoadFlowParametersTest;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * @author Hugo Kulesza {@literal <hugo.kulesza at rte-france.com>}
+ */
+class LoadFlowDefaultParametersLoaderTest {
+
+    @Test
+    void testLoadParametersFromClassPath() {
+        LoadFlowDefaultParametersLoaderMock loader = new LoadFlowDefaultParametersLoaderMock("test");
+
+        LoadFlowParameters parameters = new LoadFlowParameters(List.of(loader));
+
+        List<Extension<LoadFlowParameters>> extensions = parameters.getExtensions().stream().toList();
+        assertEquals(1, extensions.size());
+        JsonLoadFlowParametersTest.DummyExtension dummyExtension = (JsonLoadFlowParametersTest.DummyExtension) extensions.get(0);
+        assertEquals(5, dummyExtension.getParameterDouble());
+    }
+
+    @Test
+    void testConflictBetweenDefaultParametersLoader() {
+        LoadFlowDefaultParametersLoaderMock loader1 = new LoadFlowDefaultParametersLoaderMock("test1");
+        LoadFlowDefaultParametersLoaderMock loader2 = new LoadFlowDefaultParametersLoaderMock("test2");
+
+        LoadFlowParameters parameters = new LoadFlowParameters(List.of(loader1, loader2));
+        List<Extension<LoadFlowParameters>> extensions = parameters.getExtensions().stream().toList();
+        assertEquals(0, extensions.size());
+    }
+}

loadflow/loadflow-api/src/test/java/com/powsybl/loadflow/json/JsonLoadFlowParametersTest.java

@@ -259,7 +259,7 @@ private static ObjectMapper createMapper() {
 
         @Override
         public DummyExtension deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
-            return new DummyExtension();
+            return createMapper().readValue(jsonParser, DummyExtension.class);
         }
 
         @Override