Fix string concatenation loops (SpotBugs SBSC)

.github/scripts/generate-quality-report.py

@@ -773,7 +773,8 @@ def main() -> None:
             "SA_FIELD_SELF_ASSIGNMENT",
             "UC_USELESS_CONDITION",
             "EC_UNRELATED_TYPES",
-            "EQ_ALWAYS_FALSE"
+            "EQ_ALWAYS_FALSE",
+            "SBSC_USE_STRINGBUFFER_CONCATENATION"
         }
         violations = [
             f for f in spotbugs.findings

CodenameOne/src/com/codename1/ads/InnerActive.java

@@ -144,11 +144,11 @@ public void initService(Ads ads) {
         String[] keywords = ads.getKeywords();
         if (keywords != null && keywords.length > 0) {
             int klen = keywords.length;
-            String k = "";
+            StringBuilder k = new StringBuilder();
             for (int i = 0; i < klen; i++) {
-                k += "," + keywords[i];
+                k.append(",").append(keywords[i]);
             }
-            addParam(this, "k", k.substring(1));
+            addParam(this, "k", k.toString().substring(1));
         }
         if (testAds) {
             addParam(this, "test", "1");

CodenameOne/src/com/codename1/facebook/FaceBookAccess.java

@@ -218,10 +218,12 @@ public Oauth2 createOAuth() {
         String scope = "";
         if (permissions != null && permissions.length > 0) {
             int plen = permissions.length;
+            StringBuilder scopeBuilder = new StringBuilder();
             for (int i = 0; i < plen; i++) {
                 String permission = permissions[i];
-                scope += permission + ",";
+                scopeBuilder.append(permission).append(",");
             }
+            scope = scopeBuilder.toString();
             scope = scope.substring(0, scope.length() - 1);
         }
         Hashtable additionalParams = new Hashtable();
@@ -1221,21 +1223,21 @@ public void getUsersDetails(String[] usersIds, String[] fields, final ActionList
         checkAuthentication();
 
         final FacebookRESTService con = new FacebookRESTService(token, "https://api.facebook.com/method/users.getInfo", false);
-        String ids = usersIds[0];
+        StringBuilder ids = new StringBuilder(usersIds[0]);
         int ulen = usersIds.length;
         for (int i = 1; i < ulen; i++) {
-            ids += "," + usersIds[i];
+            ids.append(",").append(usersIds[i]);
 
         }
-        con.addArgumentNoEncoding("uids", ids);
+        con.addArgumentNoEncoding("uids", ids.toString());
 
-        String fieldsStr = fields[0];
+        StringBuilder fieldsStr = new StringBuilder(fields[0]);
         int flen = fields.length;
         for (int i = 1; i < flen; i++) {
-            fieldsStr += "," + fields[i];
+            fieldsStr.append(",").append(fields[i]);
 
         }
-        con.addArgumentNoEncoding("fields", fieldsStr);
+        con.addArgumentNoEncoding("fields", fieldsStr.toString());
         con.addArgument("format", "json");
 
         con.addResponseListener(new ActionListener() {

CodenameOne/src/com/codename1/io/Log.java

@@ -335,10 +335,12 @@ public static String getLogContent() {
                 Reader r = Util.getReader(FileSystemStorage.getInstance().openInputStream(instance.getFileURL()));
                 char[] buffer = new char[1024];
                 int size = r.read(buffer);
+                StringBuilder textBuilder = new StringBuilder();
                 while (size > -1) {
-                    text += new String(buffer, 0, size);
+                    textBuilder.append(new String(buffer, 0, size));
                     size = r.read(buffer);
                 }
+                text = textBuilder.toString();
                 r.close();
             }
             return text;

CodenameOne/src/com/codename1/io/Oauth2.java

@@ -385,26 +385,26 @@ public void actionPerformed(ActionEvent ev) {
     }
 
     private String buildURL() {
-        String URL = oauth2URL + "?client_id=" + Util.encodeUrl(clientId)
-                + "&redirect_uri=" + Util.encodeUrl(redirectURI);
+        StringBuilder URL = new StringBuilder(oauth2URL + "?client_id=" + Util.encodeUrl(clientId)
+                + "&redirect_uri=" + Util.encodeUrl(redirectURI));
         if (scope != null) {
-            URL += "&scope=" + Util.encodeUrl(scope);
+            URL.append("&scope=").append(Util.encodeUrl(scope));
         }
         if (clientSecret != null) {
-            URL += "&response_type=code";
+            URL.append("&response_type=code");
         } else {
-            URL += "&response_type=token";
+            URL.append("&response_type=token");
         }
 
         if (additionalParams != null) {
             Enumeration e = additionalParams.keys();
             while (e.hasMoreElements()) {
                 String key = (String) e.nextElement();
                 String val = additionalParams.get(key).toString();
-                URL += "&" + Util.encodeUrl(key) + "=" + Util.encodeUrl(val);
+                URL.append("&").append(Util.encodeUrl(key)).append("=").append(Util.encodeUrl(val));
             }
         }
-        return URL;
+        return URL.toString();
     }
 
     private Component createLoginComponent(final ActionListener al, final Form frm, final Form backToForm, final Dialog progress) {

CodenameOne/src/com/codename1/io/Util.java

@@ -2492,11 +2492,12 @@ private static String append(String a, int in) {
 
         private static String append(String a, long in, int length) {
             int lim = (length << 2) - 4;
+            StringBuilder sb = new StringBuilder(a);
             while (lim >= 0) {
-                a += (DIGITS[(byte) (in >> lim) & 0x0f]);
+                sb.append((DIGITS[(byte) (in >> lim) & 0x0f]));
                 lim -= 4;
             }
-            return a;
+            return sb.toString();
         }
 
         private static long getUniqueDeviceID() {
@@ -2537,13 +2538,13 @@ private static long generateLongFromDeviceInfo() {
          * @return
          */
         private static String sanitizeString(String input) {
-            String result = "";
+            StringBuilder result = new StringBuilder();
             for (char myChar : input.toCharArray()) {
                 if ((myChar >= '0' && myChar <= '9') || (myChar >= 'a' && myChar <= 'z') || (myChar >= 'A' && myChar <= 'Z')) {
-                    result += myChar;
+                    result.append(myChar);
                 }
             }
-            return result.substring(0, Math.min(10, result.length())).toUpperCase();
+            return result.toString().substring(0, Math.min(10, result.length())).toUpperCase();
         }
 
         /**

CodenameOne/src/com/codename1/properties/PropertyXMLElement.java

@@ -372,22 +372,22 @@ public String toString() {
     @Override
     public String toString(String spacing) {
 
-        String str = spacing;
-        str += "<" + getTagName();
+        StringBuilder str = new StringBuilder(spacing);
+        str.append("<").append(getTagName());
         Hashtable attributes = getAttributes();
         if (attributes != null) {
             for (Enumeration e = attributes.keys(); e.hasMoreElements(); ) {
                 String attrStr = (String) e.nextElement();
                 String val = (String) attributes.get(attrStr);
-                str += " " + attrStr + "='" + val + "'";
+                str.append(" ").append(attrStr).append("='").append(val).append("'");
             }
         }
-        str += ">\n";
+        str.append(">\n");
         Vector children = getChildren();
         for (int i = 0; i < children.size(); i++) {
-            str += ((Element) children.get(i)).toString(spacing + ' ');
+            str.append(((Element) children.get(i)).toString(spacing + ' '));
         }
-        str += spacing + "</" + getTagName() + ">\n";
-        return str;
+        str.append(spacing).append("</").append(getTagName()).append(">\n");
+        return str.toString();
     }
 }

CodenameOne/src/com/codename1/testing/TestUtils.java

@@ -262,12 +262,12 @@ private static String toString(int[] p) {
         if (p.length == 0) {
             return "{}";
         }
-        String s = "{" + p[0];
+        StringBuilder s = new StringBuilder("{" + p[0]);
         for (int iter = 1; iter < p.length; iter++) {
-            s += ", " + p[iter];
+            s.append(", ").append(p[iter]);
 
         }
-        return s + "}";
+        return s.append("}").toString();
     }
 
     /**

CodenameOne/src/com/codename1/ui/ComponentSelector.java

@@ -2229,12 +2229,13 @@ public ComponentSelector addTags(String... tags) {
                 existing = "";
             }
 
+            StringBuilder existingBuilder = new StringBuilder(existing);
             for (String tag : tags) {
-                if (existing.indexOf(" " + tag + " ") == -1) {
-                    existing += " " + tag + " ";
+                if (existingBuilder.toString().indexOf(" " + tag + " ") == -1) {
+                    existingBuilder.append(" ").append(tag).append(" ");
                 }
             }
-            c.putClientProperty(PROPERTY_TAG, existing);
+            c.putClientProperty(PROPERTY_TAG, existingBuilder.toString());
 
         }
         return this;
@@ -2266,10 +2267,11 @@ public ComponentSelector removeTags(String... tags) {
                 c.putClientProperty(PROPERTY_TAG, null);
                 continue;
             }
+            StringBuilder existingBuilder = new StringBuilder(existing);
             for (String tag : existingSet) {
-                existing += " " + tag + " ";
+                existingBuilder.append(" ").append(tag).append(" ");
             }
-            c.putClientProperty(PROPERTY_TAG, existing);
+            c.putClientProperty(PROPERTY_TAG, existingBuilder.toString());
         }
         return this;
     }

CodenameOne/src/com/codename1/ui/Container.java

@@ -3095,18 +3095,18 @@ protected String paramString() {
      * @return the container components objects as list of Strings
      */
     private String getComponentsNames() {
-        String ret = "[";
+        StringBuilder ret = new StringBuilder("[");
         int componentCount = components.size();
         for (int iter = 0; iter < componentCount; iter++) {
             Component cmp = components.get(iter);
             String className = cmp.getClass().getName();
-            ret += className.substring(className.lastIndexOf('.') + 1) + ", ";
+            ret.append(className.substring(className.lastIndexOf('.') + 1)).append(", ");
         }
         if (ret.length() > 1) {
-            ret = ret.substring(0, ret.length() - 2);
+            ret.setLength(ret.length() - 2);
         }
-        ret = ret + "]";
-        return ret;
+        ret.append("]");
+        return ret.toString();
     }
 
     /**

CodenameOne/src/com/codename1/ui/TextArea.java

@@ -1137,25 +1137,25 @@ private void initRowString() {
             if (useStringWidth || actAsLabel) {
                 // fix for an infinite loop issue: http://forums.java.net/jive/thread.jspa?messageID=482802
                 //currentRowWidth = 0;
-                String currentRow = "";
+                StringBuilder currentRowBuilder = new StringBuilder();
 
                 // search for "space" character at close as possible to the end of the row
                 for (i = to; i < textLength && fastCharWidthCheck(text, from, i - from + 1, textAreaWidth, charWidth, font); i++) {
                     char c = text[i];
                     /*if(updateRowWidth(c, font) >= textAreaWidth) {
                         break;
                     }*/
-                    currentRow += c;
+                    currentRowBuilder.append(c);
                     if (i < textLength - 1 && Character.isSurrogatePair(c, text[i + 1])) {
                         // Surrogate pairs (e.g. emojis) shouldn't be split up.
-                        currentRow += text[++i];
+                        currentRowBuilder.append(text[++i]);
                         maxLength += 2;
-                        if (font.stringWidth(currentRow) >= textAreaWidth) {
+                        if (font.stringWidth(currentRowBuilder.toString()) >= textAreaWidth) {
                             break;
                         }
                         continue;
                     }
-                    if (font.stringWidth(currentRow) >= textAreaWidth) {
+                    if (font.stringWidth(currentRowBuilder.toString()) >= textAreaWidth) {
                         break;
                     }
                     if (unsupported.indexOf(c) > -1) {

CodenameOne/src/com/codename1/ui/html/CSSEngine.java

@@ -622,7 +622,7 @@ private void setTextTransformRecursive(Component cmp, int transformType) {
 
                     String text = label.getText();
 
-                    String newText = "";
+                    StringBuilder newText = new StringBuilder();
                     boolean capNextLetter = true;
                     for (int i = 0; i < text.length(); i++) {
                         char c = text.charAt(i);
@@ -634,9 +634,9 @@ private void setTextTransformRecursive(Component cmp, int transformType) {
                             }
                             capNextLetter = false;
                         }
-                        newText += c;
+                        newText.append(c);
                     }
-                    label.setText(newText);
+                    label.setText(newText.toString());
                     break;
                 default:
                     break;
@@ -803,25 +803,25 @@ private void setNowrapRecursive(final HTMLElement element) {
             String text = element.getText();
             final Vector ui = element.getUi();
             if ((text != null) && (ui != null) && (ui.size() > 1)) { //If it's just one word or already no-wrapped, no need to process
-                String word = "";
-                String newText = "";
+                StringBuilder word = new StringBuilder();
+                StringBuilder newText = new StringBuilder();
                 for (int c = 0; c < text.length(); c++) {
                     char ch = text.charAt(c);
                     if ((ch == ' ') || (ch == '\n') || (ch == '\r') || (ch == '\t')) {
-                        if (!word.equals("")) {
-                            newText += word + " ";
-                            word = "";
+                        if (word.length() > 0) {
+                            newText.append(word).append(" ");
+                            word.setLength(0);
                         }
                     } else {
-                        word += ch;
+                        word.append(ch);
                     }
                 }
-                if (!word.equals("")) {
-                    newText += word + " ";
+                if (word.length() > 0) {
+                    newText.append(word).append(" ");
                 }
 
                 final Label label = (Label) ui.elementAt(0);
-                setNowrapText(label, ui, newText, element);
+                setNowrapText(label, ui, newText.toString(), element);
             }
         }