[WIP] Adds the ability to specify [camelN] as a title-related field m…

…arker for citation key generation (#10772)

* add `camelShort` citation key marker

Add the ability to set a citation key marker `camelShort` that is identical to the `camel` marker but with a maximum of 7 words.

* change name to `shortcamel` 

change name to `shortcamel` to match current naming scheme

* Update src/main/java/org/jabref/logic/citationkeypattern/BracketedPattern.java

* refactor [shortcamel] title to instead use [camelN] to select N words from camelCase title. Not functional yet.

* refactor getTitleWordsWithSpaces to call getSomeWords so that the new function can be used for camelN

* add [camelN] functionality

* add test cases for [camelN]

* add `[camelN]` to changelog

* remove trailing whitespace

---------

Co-authored-by: Christoph <siedlerkiller@gmail.com>

CHANGELOG.md

@@ -18,6 +18,7 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - We added ability to jump to an entry in the command line using `-j CITATIONKEY`. [koppor#540](https://github.com/koppor/jabref/issues/540)
 - We added a new boolean to the style files for Openoffice/Libreoffice integration to switch between ZERO_WIDTH_SPACE (default) and no space. [#10843](https://github.com/JabRef/jabref/pull/10843)
 - We added the possibility to redownload files that had been present but are no longer in the specified location. [#10848](https://github.com/JabRef/jabref/issues/10848)
+- We added the citation key pattern `[camelN]`. Equivalent to the first N words of the `[camel]` pattern.
 
 ### Changed
 

src/main/java/org/jabref/logic/citationkeypattern/BracketedPattern.java

@@ -454,6 +454,9 @@ public static String getFieldValue(BibEntry entry, String pattern, Character key
             } else if ("veryshorttitle".equals(pattern)) {
                 return getTitleWords(1,
                         removeSmallWords(entry.getResolvedFieldOrAlias(StandardField.TITLE, database).orElse("")));
+            } else if (pattern.matches("camel[\\d]+")) {
+                int num = Integer.parseInt(pattern.substring(5));
+                return getCamelizedTitle_N(entry.getResolvedFieldOrAlias(StandardField.TITLE, database).orElse(""), num);
             } else if ("camel".equals(pattern)) {
                 return getCamelizedTitle(entry.getResolvedFieldOrAlias(StandardField.TITLE, database).orElse(""));
             } else if ("shortyear".equals(pattern)) {
@@ -662,6 +665,36 @@ private static String camelizeTitle(String title) {
         return stringBuilder.toString();
     }
 
+    /**
+     * Capitalises and concatenates the words out of the "title" field in the given BibTeX entry, to a maximum of N words.
+     */
+    public static String getCamelizedTitle_N(String title, int number) {
+        return keepLettersAndDigitsOnly(camelizeTitle_N(title, number));
+    }
+
+    private static String camelizeTitle_N(String title, int number) {
+        StringBuilder stringBuilder = new StringBuilder();
+        String formattedTitle = formatTitle(title);
+
+        try (Scanner titleScanner = new Scanner(formattedTitle)) {
+            while (titleScanner.hasNext()) {
+                String word = titleScanner.next();
+
+                // Camelize the word
+                word = word.substring(0, 1).toUpperCase(Locale.ROOT) + word.substring(1);
+
+                if (stringBuilder.length() > 0) {
+                    stringBuilder.append(' ');
+                }
+                stringBuilder.append(word);
+            }
+        }
+
+        String camelString = stringBuilder.toString();
+
+        return getSomeWords(number, camelString);
+    }
+
     /**
      * Capitalises the significant words of the "title" field in the given BibTeX entry
      */
@@ -704,7 +737,11 @@ public static String removeSmallWords(String title) {
     private static String getTitleWordsWithSpaces(int number, String title) {
         String formattedTitle = formatTitle(title);
 
-        try (Scanner titleScanner = new Scanner(formattedTitle)) {
+        return getSomeWords(number, formattedTitle);
+    }
+
+    private static String getSomeWords(int number, String string) {
+        try (Scanner titleScanner = new Scanner(string)) {
             return titleScanner.tokens()
                                .limit(number)
                                .collect(Collectors.joining(" "));

src/test/java/org/jabref/logic/citationkeypattern/BracketedPatternTest.java

@@ -543,6 +543,19 @@ void expandBracketsDoesNotTruncateWithoutAnArgumentToTruncateModifier() {
                 BracketedPattern.expandBrackets("[fulltitle:truncate]", ';', dbentry, database));
     }
 
+    /**
+     * Test the [camelN] title marker.
+     */
+    @Test
+    void expandBracketsCamelNTitle() {
+        assertEquals("Open",
+                BracketedPattern.expandBrackets("[camel1]", ';', dbentry, database));
+        assertEquals("OpenSourceSoftwareAnd",
+                BracketedPattern.expandBrackets("[camel4]", ';', dbentry, database));
+        assertEquals("OpenSourceSoftwareAndThePrivateCollectiveInnovationModelIssues",
+                BracketedPattern.expandBrackets("[camel10]", ';', dbentry, database));
+    }
+
     @Test
     void expandBracketsWithAuthorStartingWithBrackets() {
         // Issue https://github.com/JabRef/jabref/issues/3920