Support for exporting to YAML format

CHANGELOG.md

@@ -15,6 +15,7 @@ Note that this project **does not** adhere to [Semantic Versioning](http://semve
 - We added a query parser and mapping layer to enable conversion of queries formulated in simplified lucene syntax by the user into api queries. [#6799](https://github.com/JabRef/jabref/pull/6799)
 - We added some basic functionality to customise the look of JabRef by importing a css theme file. [#5790](https://github.com/JabRef/jabref/issues/5790)
 - We added connection check function in network preference setting [#6560](https://github.com/JabRef/jabref/issues/6560)
+- We added support for exporting to YAML. [#6974](https://github.com/JabRef/jabref/issues/6974)
 
 ### Changed
 
@@ -48,6 +49,7 @@ Note that this project **does not** adhere to [Semantic Versioning](http://semve
 - We fixed an issue where it was impossible to connect to OpenOffice/LibreOffice on Mac OSX. [#6970](https://github.com/JabRef/jabref/pull/6970)
 - We fixed an issue with the python script used by browser plugins that failed to locate JabRef if not installed in its default location. [#6963](https://github.com/JabRef/jabref/pull/6963/files)
 - We fixed an issue where identity column header had incorrect foreground color in the  Dark theme. [#6796](https://github.com/JabRef/jabref/issues/6796)
+- We fixed an issue where the RIS exporter added extra blank lines.[#7007](https://github.com/JabRef/jabref/pull/7007/files)
 
 ### Removed
 

src/main/java/org/jabref/logic/exporter/ExporterFactory.java

@@ -49,8 +49,9 @@ public static ExporterFactory create(List<TemplateExporter> customFormats,
         exporters.add(new TemplateExporter("ISO 690", "iso690txt", "iso690", "iso690txt", StandardFileType.TXT, layoutPreferences, savePreferences));
         exporters.add(new TemplateExporter("Endnote", "endnote", "EndNote", "endnote", StandardFileType.TXT, layoutPreferences, savePreferences));
         exporters.add(new TemplateExporter("OpenOffice/LibreOffice CSV", "oocsv", "openoffice-csv", "openoffice", StandardFileType.CSV, layoutPreferences, savePreferences));
-        exporters.add(new TemplateExporter("RIS", "ris", "ris", "ris", StandardFileType.RIS, layoutPreferences, savePreferences).withEncoding(StandardCharsets.UTF_8));
+        exporters.add(new TemplateExporter("RIS", "ris", "ris", "ris", StandardFileType.RIS, layoutPreferences, savePreferences, true).withEncoding(StandardCharsets.UTF_8));
         exporters.add(new TemplateExporter("MIS Quarterly", "misq", "misq", "misq", StandardFileType.RTF, layoutPreferences, savePreferences));
+        exporters.add(new TemplateExporter("CSL YAML", "yaml", "yaml", null, StandardFileType.YAML, layoutPreferences, savePreferences, true));
         exporters.add(new BibTeXMLExporter());
         exporters.add(new OpenOfficeDocumentCreator());
         exporters.add(new OpenDocumentSpreadsheetCreator());

src/main/java/org/jabref/logic/exporter/TemplateExporter.java

@@ -14,7 +14,6 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import java.util.regex.Pattern;
 
 import org.jabref.logic.layout.Layout;
 import org.jabref.logic.layout.LayoutFormatterPreferences;
@@ -34,14 +33,6 @@
 public class TemplateExporter extends Exporter {
 
     private static final String LAYOUT_PREFIX = "/resource/layout/";
-
-    /**
-     * A regular expression that matches blank lines
-     *
-     * ?m activates "multimode", which makes ^ match line starts/ends.
-     * \\s simply marks any whitespace character
-     */
-    private static final Pattern BLANK_LINE_MATCHER = Pattern.compile("(?m)^\\s");
     private static final String LAYOUT_EXTENSION = ".layout";
     private static final String FORMATTERS_EXTENSION = ".formatters";
     private static final String BEGIN_INFIX = ".begin";
@@ -58,8 +49,7 @@ public class TemplateExporter extends Exporter {
     private boolean deleteBlankLines;
 
     /**
-     * Initialize another export format based on templates stored in dir with
-     * layoutFile lfFilename.
+     * Initialize another export format based on templates stored in dir with layoutFile lfFilename.
      *
      * @param displayName Name to display to the user.
      * @param consoleName Name to call this format in the console.
@@ -72,8 +62,7 @@ public TemplateExporter(String displayName, String consoleName, String lfFileNam
     }
 
     /**
-     * Initialize another export format based on templates stored in dir with
-     * layoutFile lfFilename.
+     * Initialize another export format based on templates stored in dir with layoutFile lfFilename.
      *
      * @param name              to display to the user and to call this format in the console.
      * @param lfFileName        Name of the main layout file.
@@ -87,8 +76,7 @@ public TemplateExporter(String name, String lfFileName, String extension, Layout
     }
 
     /**
-     * Initialize another export format based on templates stored in dir with
-     * layoutFile lfFilename.
+     * Initialize another export format based on templates stored in dir with layoutFile lfFilename.
      *
      * @param displayName       Name to display to the user.
      * @param consoleName       Name to call this format in the console.
@@ -112,27 +100,33 @@ public TemplateExporter(String displayName, String consoleName, String lfFileNam
     }
 
     /**
-     * Initialize another export format based on templates stored in dir with
-     * layoutFile lfFilename.
-     * The display name is automatically derived from the FileType
+     * Initialize another export format based on templates stored in dir with layoutFile lfFilename.
      *
+     * @param displayName       Name to display to the user.
      * @param consoleName       Name to call this format in the console.
      * @param lfFileName        Name of the main layout file.
      * @param directory         Directory in which to find the layout file.
      * @param extension         Should contain the . (for instance .txt).
      * @param layoutPreferences Preferences for layout
      * @param savePreferences   Preferences for saving
-     * @param deleteBlankLines  If blank lines should be remove (default: false)
+     * @param deleteBlankLines  if blank lines should be removed (default: false)
      */
-    public TemplateExporter(String consoleName, String lfFileName, String directory, StandardFileType extension, LayoutFormatterPreferences layoutPreferences, SavePreferences savePreferences, boolean deleteBlankLines) {
-        this(consoleName, consoleName, lfFileName, directory, extension, layoutPreferences, savePreferences);
+    public TemplateExporter(String displayName, String consoleName, String lfFileName, String directory, FileType extension,
+                            LayoutFormatterPreferences layoutPreferences, SavePreferences savePreferences, boolean deleteBlankLines) {
+        super(consoleName, displayName, extension);
+        if (Objects.requireNonNull(lfFileName).endsWith(LAYOUT_EXTENSION)) {
+            this.lfFileName = lfFileName.substring(0, lfFileName.length() - LAYOUT_EXTENSION.length());
+        } else {
+            this.lfFileName = lfFileName;
+        }
+        this.directory = directory;
+        this.layoutPreferences = layoutPreferences;
+        this.savePreferences = savePreferences;
         this.deleteBlankLines = deleteBlankLines;
     }
 
     /**
-     * Indicate whether this is a custom export. A custom export looks for its
-     * layout files using a normal file path, while a built-in export looks in
-     * the classpath.
+     * Indicate whether this is a custom export. A custom export looks for its layout files using a normal file path, while a built-in export looks in the classpath.
      *
      * @param custom true to indicate a custom export format.
      */
@@ -141,8 +135,7 @@ public void setCustomExport(boolean custom) {
     }
 
     /**
-     * Set an encoding which will be used in preference to the default value
-     * obtained from the basepanel.
+     * Set an encoding which will be used in preference to the default value obtained from the basepanel.
      *
      * @param encoding The name of the encoding to use.
      */
@@ -152,11 +145,9 @@ public TemplateExporter withEncoding(Charset encoding) {
     }
 
     /**
-     * This method should return a reader from which the given layout file can
-     * be read.
+     * This method should return a reader from which the given layout file can be read.
      * <p>
-     * Subclasses of TemplateExporter are free to override and provide their own
-     * implementation.
+     * Subclasses of TemplateExporter are free to override and provide their own implementation.
      *
      * @param filename the filename
      * @return a newly created reader
@@ -278,8 +269,12 @@ public void export(final BibDatabaseContext databaseContext, final Path file,
                 // Write the entry
                 if (layout != null) {
                     if (deleteBlankLines) {
-                        String withoutBlankLines = BLANK_LINE_MATCHER.matcher(layout.doLayout(entry, databaseContext.getDatabase())).replaceAll("");
-                        ps.write(withoutBlankLines);
+                        String[] lines = layout.doLayout(entry, databaseContext.getDatabase()).split("\n");
+                        for (String line : lines) {
+                            if (!line.isBlank() && !line.isEmpty()) {
+                                ps.write(line);
+                            }
+                        }
                     } else {
                         ps.write(layout.doLayout(entry, databaseContext.getDatabase()));
                     }
@@ -316,9 +311,7 @@ public void export(final BibDatabaseContext databaseContext, final Path file,
     }
 
     /**
-     * See if there is a name formatter file bundled with this export format. If so, read
-     * all the name formatters so they can be used by the filter layouts.
-     *
+     * See if there is a name formatter file bundled with this export format. If so, read all the name formatters so they can be used by the filter layouts.
      */
     private void readFormatterFile() {
         File formatterFile = new File(lfFileName + FORMATTERS_EXTENSION);

src/main/java/org/jabref/logic/util/StandardFileType.java

@@ -41,7 +41,8 @@ public enum StandardFileType implements FileType {
     JSON("json"),
     XMP("xmp"),
     ZIP("zip"),
-    CSS("css");
+    CSS("css"),
+    YAML("yaml");
 
     private final List<String> extensions;
 

src/main/resources/resource/layout/yaml.begin.layout

@@ -0,0 +1,2 @@
+---
+references:

src/main/resources/resource/layout/yaml.end.layout

@@ -0,0 +1 @@
+---

src/main/resources/resource/layout/yaml.layout

@@ -0,0 +1,14 @@
+- id: \citationkey
+\begin{type}  type: \type\end{type}
+\begin{author}
+  author:
+  - literal: "\author"
+\end{author}
+\begin{title}  title: "\title"\end{title}
+\begin{shorttitle}  title-short: "\shorttitle"\end{shorttitle}
+\begin{date}  issued: \date\end{date}
+\begin{url}  url: \url\end{url}
+\begin{doi}  doi: \doi\end{doi}
+\begin{volume}  volume: \volume\end{volume}
+\begin{number}  number: \number\end{number}
+\begin{urldate}  accessed: \urldate\end{urldate}

src/test/java/org/jabref/logic/exporter/YamlExporterTest.java

@@ -0,0 +1,79 @@
+package org.jabref.logic.exporter;
+
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.jabref.logic.layout.LayoutFormatterPreferences;
+import org.jabref.logic.xmp.XmpPreferences;
+import org.jabref.model.database.BibDatabaseContext;
+import org.jabref.model.entry.BibEntry;
+import org.jabref.model.entry.field.StandardField;
+import org.jabref.model.entry.types.StandardEntryType;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+import org.mockito.Answers;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.mock;
+
+public class YamlExporterTest {
+
+    public Charset charset;
+    private Exporter yamlExporter;
+    private BibDatabaseContext databaseContext;
+
+    @BeforeEach
+    public void setUp() throws Exception {
+        List<TemplateExporter> customFormats = new ArrayList<>();
+        LayoutFormatterPreferences layoutPreferences = mock(LayoutFormatterPreferences.class, Answers.RETURNS_DEEP_STUBS);
+        SavePreferences savePreferences = mock(SavePreferences.class);
+        XmpPreferences xmpPreferences = mock(XmpPreferences.class);
+        ExporterFactory exporterFactory = ExporterFactory.create(customFormats, layoutPreferences, savePreferences, xmpPreferences);
+
+        databaseContext = new BibDatabaseContext();
+        charset = StandardCharsets.UTF_8;
+        yamlExporter = exporterFactory.getExporterByName("yaml").get();
+    }
+
+    @Test
+    public final void exportForNoEntriesWritesNothing(@TempDir Path tempFile) throws Exception {
+        Path file = tempFile.resolve("ThisIsARandomlyNamedFile");
+        Files.createFile(file);
+        yamlExporter.export(databaseContext, tempFile, charset, Collections.emptyList());
+        assertEquals(Collections.emptyList(), Files.readAllLines(file));
+    }
+
+    @Test
+    public final void exportCorrectContent(@TempDir Path tempFile) throws Exception {
+        BibEntry entry = new BibEntry(StandardEntryType.Article);
+        entry.withCitationKey("test");
+        entry.withField(StandardField.AUTHOR, "Test Author");
+        entry.withField(StandardField.TITLE, "Test Title");
+        entry.withField(StandardField.URL, "http://example.com");
+        entry.withField(StandardField.YEAR, "2020");
+
+        Path file = tempFile.resolve("RandomFileName");
+        Files.createFile(file);
+        yamlExporter.export(databaseContext, file, charset, Collections.singletonList(entry));
+
+        List<String> lines = new ArrayList<>();
+        lines.add("---");
+        lines.add("references:");
+        lines.add("- id: test");
+        lines.add("  author:");
+        lines.add("  - literal: \"Test Author\"");
+        lines.add("  title: \"Test Title\"");
+        lines.add("  issued: 2020");
+        lines.add("  url: http://example.com");
+        lines.add("---");
+
+        assertEquals(lines, Files.readAllLines(file));
+    }
+}