Optimizations

src/com/intellij/advancedExpressionFolding/AdvancedExpressionFoldingBuilder.java

@@ -23,9 +23,11 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-public class AdvancedExpressionFoldingBuilder extends FoldingBuilderEx {
+import static com.intellij.advancedExpressionFolding.PropertyUtil.guessPropertyName;
 
+public class AdvancedExpressionFoldingBuilder extends FoldingBuilderEx {
     private static final FoldingDescriptor[] NO_DESCRIPTORS = new FoldingDescriptor[0];
+    private static final Pattern GENERICS_PATTERN = Pattern.compile("<[^<>]*>");
 
     private static Set<String> supportedMethods = new HashSet<String>() {
         {
@@ -1297,12 +1299,10 @@ private static Variable getVariableExpression(PsiElement element, boolean copy)
 
     @NotNull
     private static String eraseGenerics(@NotNull String signature) {
-        String re = "<[^<>]*>";
-        Pattern p = Pattern.compile(re);
-        Matcher m = p.matcher(signature);
+        Matcher m = GENERICS_PATTERN.matcher(signature);
         while (m.find()) {
             signature = m.replaceAll("");
-            m = p.matcher(signature);
+            m = GENERICS_PATTERN.matcher(signature);
         }
         return signature;
     }
@@ -1828,29 +1828,6 @@ private static String charAt(@NotNull Document document, int position) {
         return document.getText(TextRange.create(position, position + 1));
     }
 
-    @NotNull
-    private static String guessPropertyName(@NotNull String text) {
-        StringBuilder sb = new StringBuilder();
-        if (text.startsWith("get")) {
-            sb.append(text.substring(3));
-        } else if (text.startsWith("set")) {
-            sb.append(text.substring(3));
-        } else if (text.startsWith("is")) {
-            sb.append(text.substring(2));
-        } else {
-            sb.append(text);
-        }
-        for (int i = 0; i < sb.length(); i++) {
-            if (Character.isUpperCase(sb.charAt(i)) &&
-                    (i == sb.length() - 1 || Character.isUpperCase(sb.charAt(i + 1)) || i == 0)) {
-                sb.setCharAt(i, Character.toLowerCase(sb.charAt(i)));
-            } else if (Character.isLowerCase(sb.charAt(i))) {
-                break;
-            }
-        }
-        return sb.toString();
-    }
-
     @Nullable
     private static NumberLiteral getSlicePosition(@NotNull PsiElement parent, @NotNull Expression qualifierExpression,
                                                   @NotNull PsiBinaryExpression a2b, @NotNull Document document) {
@@ -1928,8 +1905,8 @@ public FoldingDescriptor[] buildFoldRegions(@NotNull PsiElement element, @NotNul
         try {
             @Nullable Expression expression = getNonSyntheticExpression(element, document);
             if (expression != null && expression.supportsFoldRegions(document, null)) {
-                allDescriptors = new ArrayList<>();
                 FoldingDescriptor[] descriptors = expression.buildFoldRegions(expression.getElement(), document, null);
+                allDescriptors = new ArrayList<>();
                 Collections.addAll(allDescriptors, descriptors);
             }
             if (expression == null || expression.isNested()) {
@@ -1939,12 +1916,11 @@ public FoldingDescriptor[] buildFoldRegions(@NotNull PsiElement element, @NotNul
                         if (allDescriptors == null) {
                             allDescriptors = new ArrayList<>();
                         }
-                        allDescriptors.addAll(Arrays.asList(descriptors));
+                        Collections.addAll(allDescriptors, descriptors);
                     }
                 }
             }
-        } catch (IndexNotReadyException e) {
-            // ignore
+        } catch (IndexNotReadyException ignore) {
         }
         return allDescriptors != null ? allDescriptors.toArray(NO_DESCRIPTORS) : NO_DESCRIPTORS;
     }
@@ -1971,4 +1947,5 @@ public boolean isCollapsedByDefault(@NotNull ASTNode astNode) {
         }
         return false;
     }
+
 }

src/com/intellij/advancedExpressionFolding/Expression.java

@@ -151,13 +151,13 @@ protected static String subscript(String str) {
     }
 
     private static String map(String str, Map<Character, Character> subscriptMapping) {
-        StringBuilder sb = new StringBuilder();
+        StringBuilder sb = new StringBuilder(str.length());
         for (int i = 0; i < str.length(); i++) {
             Character c = subscriptMapping.get(str.charAt(i));
             if (c == null) {
                 return null;
             } else if (!c.equals('❤')) {
-                sb.append(c);
+                sb.append((char) c);
             }
         }
         return sb.toString();

src/com/intellij/advancedExpressionFolding/InterpolatedString.java

@@ -102,12 +102,12 @@ public String getPlaceholderText() {
                     ? operands.get(i + 1).getTextRange().getStartOffset() + 1
                     : operands.get(i + 1).getTextRange().getStartOffset();
             int fI = i;
-            StringBuilder sI = new StringBuilder().append(buf[0]);
+            StringBuilder sI = new StringBuilder(buf[0].length() + 2).append(buf[0]);
             if (!(operands.get(fI + 1) instanceof CharSequenceLiteral)) {
-                sI.append("$");
+                sI.append('$');
             }
             if (!(operands.get(fI + 1) instanceof Variable) && !(operands.get(fI + 1) instanceof CharSequenceLiteral)) {
-                sI.append("{");
+                sI.append('{');
                 buf[0] = "}";
             } else {
                 buf[0] = "";

src/com/intellij/advancedExpressionFolding/PropertyUtil.java

@@ -0,0 +1,29 @@
+package com.intellij.advancedExpressionFolding;
+
+import org.jetbrains.annotations.NotNull;
+
+public class PropertyUtil {
+
+    @NotNull
+    public static String guessPropertyName(@NotNull String text) {
+        StringBuilder sb = new StringBuilder();
+        if (text.startsWith("get")) {
+            sb.append(text.substring(3));
+        } else if (text.startsWith("set")) {
+            sb.append(text.substring(3));
+        } else if (text.startsWith("is")) {
+            sb.append(text.substring(2));
+        } else {
+            sb.append(text);
+        }
+        for (int i = 0; i < sb.length(); i++) {
+            if (Character.isUpperCase(sb.charAt(i)) &&
+                    (i == sb.length() - 1 || Character.isUpperCase(sb.charAt(i + 1)) || i == 0)) {
+                sb.setCharAt(i, Character.toLowerCase(sb.charAt(i)));
+            } else if (Character.isLowerCase(sb.charAt(i))) {
+                break;
+            }
+        }
+        return sb.toString();
+    }
+}

src/com/intellij/advancedExpressionFolding/Range.java

@@ -105,20 +105,13 @@ public boolean supportsFoldRegions(@NotNull Document document,
     @Override
     public FoldingDescriptor[] buildFoldRegions(@NotNull PsiElement element, @NotNull Document document, @Nullable Expression parent) {
         FoldingGroup group = FoldingGroup.newGroup(getClass().getName());
-        StringBuilder sb1 = new StringBuilder().append(" ").append(separator).append(" ");
-        if (isStartInclusive()) {
-            sb1.append("[");
-        } else {
-            sb1.append("(");
-        }
-        String p1 = sb1.toString();
-        StringBuilder sb2 = new StringBuilder();
-        if (isEndInclusive()) {
-            sb2.append("]");
-        } else {
-            sb2.append(")");
-        }
-        String p2 = sb2.toString();
+        String p1 = new StringBuilder(separator.length() + 3)
+            .append(' ')
+            .append(separator)
+            .append(' ')
+            .append(isStartInclusive() ? '[' : '(')
+            .toString();
+        String p2 = isEndInclusive() ? "]" : ")";
         ArrayList<FoldingDescriptor> descriptors = new ArrayList<>();
         descriptors.add(new FoldingDescriptor(element.getNode(),
                 TextRange.create(getOperand().getTextRange().getEndOffset(),

test/com/intellij/advancedExpressionFolding/PropertyUtilTest.java

@@ -0,0 +1,20 @@
+package com.intellij.advancedExpressionFolding;
+
+import org.junit.Test;
+
+import static com.intellij.advancedExpressionFolding.PropertyUtil.guessPropertyName;
+import static org.junit.Assert.*;
+
+public class PropertyUtilTest {
+    @Test
+    public void testGuessPropertyName() {
+        assertEquals("", guessPropertyName(""));
+        assertEquals("length", guessPropertyName("length"));
+        assertEquals("name", guessPropertyName("getName"));
+        assertEquals("name", guessPropertyName("setName"));
+        assertEquals("enabled", guessPropertyName("isEnabled"));
+        assertEquals("enabledByDefault", guessPropertyName("isEnabledByDefault"));
+        assertEquals("html", guessPropertyName("getHTML"));
+        assertEquals("htmlText", guessPropertyName("isHTMLText"));
+    }
+}