iidm new import/export modes (#46)

Author: ChamseddineBhd

docs/iidm/exporter/iidm.md

@@ -11,6 +11,14 @@ For more information about the IIDM model, see [here](../model/index.md).
 
 IIDM networks can be serialized in XML files. The IIDM exporter generates files with a `*.xiidm` extension.
 
+The IIDM exporter has three exporting modes:
+
+   - **First mode**: Exports the network and its extensions in a unique file.
+    
+   - **Second mode**: Exports the network in a file and the extensions in another file.
+    
+   - **Third mode**: Exports the network in a file and each extension type in a separate file. 
+
 # Example
 ```xml
 <?xml version="1.0" encoding="UTF-8"?>
@@ -78,10 +86,6 @@ of the network or not. Its default value is `false`.
 The `iidm.export.xml.anonymised` property is an optional property that defines if the XIIDM exporter anonymises
 all equipments in the generated file or not. Its default value is `false`.
 
-## iidm.export.xml.skip-extensions
-The `iidm.export.xml.skip-extensions` property is an optional property that defines if the XIIDM exporter skips exporting the 
-network extensions or not. Its default value is `false`.
-
 ## iidm.export.xml.topology-level
 The `iidm.export.xml.topology-level` property is an optional property that defines if the most detailed topology in which the XIIDM exporter can export the
 network. Its default value is `NODE_BREAKER`.
@@ -90,6 +94,32 @@ network. Its default value is `NODE_BREAKER`.
 The `iidm.export.xml.throw-exception-if-extension-not-found` property is an optional property that defines if the XIIDM exporter throws
 an exception if the network contains an unknown or unserializable extension or if it just ignores it. Its default value is `false`.
 
+## iidm.export.xml.export-mode
+The `iidm.export.xml.export-mode` property is an optional property that defines the export mode of the XIIDM exporter.
+The export mode can be:
+
+   - `IidmImportExportMode.UNIQUE_FILE`: in case we want to export the network and its extensions in a unique file.
+
+   - `IidmImportExportMode.EXTENSIONS_IN_ONE_SEPARATED_FILE`: in case we want to export the network in a file and  the extensions in a separate file.
+    Example: if our network `test` has extensions then the network will be exported in the `test.xiidm` file when all its extensions will be exported in `test-ext.xiidm` file. 
+
+   - `IidmImportExportMode.ONE_SEPARATED_FILE_PER_EXTENSION_TYPE`: in case we want to export network in a file and each extension type in a separate file.
+   Example: if our network `test` has two extensions `loadFoo` and `loadBar` then the network will be exported 
+    in the `test.xiidm` file when `loadFoo` and `loadBar` will be exported respectively in `test-loadFoo.xiidm` and `test-loadBar.xiidm`.
+
+The default value for this parameter is `IidmImportExportMode.NO_SEPARATED_FILE_FOR_EXTENSIONS`.
+
+## iidm.export.xml.extensions
+The `iidm.export.xml.extensions` property is an optional property that defines the list of extensions that we want to export by the XIIDM exporter. 
+By default all extensions will be exported.
+
+# Deprecated configuration properties for IIDM-XML exporter
+
+## iidm.export.xml.skip-extensions
+The `iidm.export.xml.skip-extensions` property is an optional property that defines if the XIIDM exporter skips exporting the 
+network extensions or not. Its default value is `false`.
+This property is deprecated since v2.4.0. Use the `iidm.export.xml.export-mode` property instead.
+
 # Maven configuration
 To support IIDM-XML files, add the following dependencies to the `pom.xml` file.
 ```xml

docs/iidm/importer/iidm.md

@@ -12,6 +12,14 @@ For more information about the IIDM model, see [here](../model/index.md).
 IIDM networks can be serialized in XML files. The IIDM importer supports files with the following extensions: `*.xml`,
 `*.xiidm` and `*.iidm`.
 
+The IIDM importer has three importing modes:
+
+- **First mode** : Imports the network and its extensions from a unique file.
+    
+- **Second mode** : Imports the network from a file and the extensions from another file. 
+    
+- **Third mode** : Imports the network from a file and each extension type from a separate file.
+
 # Example
 ```xml
 <?xml version="1.0" encoding="UTF-8"?>
@@ -68,6 +76,28 @@ The `iidm.import.xml.throw-exception-if-extension-not-found` property is an opti
 that defines if the XIIDM importer throws an exception while trying to import an unknown or undeserializable extension or if
 it just ignores it. Its default value is `false`.
 
+
+## iidm.import.xml.import-mode
+The `iidm.import.xml.import-mode` property is an optional property
+that defines the import mode of the XIIDM importer. 
+
+Its possible values are :
+
+   - `IidmImportExportMode.UNIQUE_FILE`: Imports the network and its extensions from a unique file.
+    
+   - `IidmImportExportMode.EXTENSIONS_IN_ONE_SEPARATED_FILE`: Imports the network from a file and the extensions from another file. 
+      In this case if the network file name is network.xiidm, the extensions file name must be network-ext.xiidm.
+    
+   - `IidmImportExportMode.ONE_SEPARATED_FILE_PER_EXTENSION_TYPE`: Imports the network from a file and each extension type from a separate file.
+      In this mode each extension file name must be networkName-extensionName.xiidm.
+      Example : if we have an extension file for the `loadFoo` extension type and our network name is `test`, the file name must be `test-loadFoo.xiidm`.
+      
+The default value of this parameter is `IidmImportExportMode.NO_SEPARATED_FILE_FOR_EXTENSIONS`.
+
+## iidm.import.xml.extensions
+The `iidm.import.xml.extensions` property is an optional property that defines the list of extensions that we want to import by the XIIDM importer. 
+By default all extensions will be imported.
+
 # Deprecated configuration properties for IIDM-XML importer
 
 ## throwExceptionIfExtensionNotFound