perf: Avoid collection copies in CtPackageImpl "empty" checks (#4848)

src/main/java/spoon/IncrementalLauncher.java

@@ -223,7 +223,7 @@ public IncrementalLauncher(Set<File> inputResources, Set<String> sourceClasspath
 
 			Collection<CtPackage> oldPackages = oldFactory.Package().getAll();
 			for (CtPackage pkg : oldPackages) {
-				if (pkg.getTypes().isEmpty() && pkg.getPackages().isEmpty() && !pkg.isUnnamedPackage()) {
+				if (pkg.isEmpty() && !pkg.isUnnamedPackage()) {
 					pkg.delete();
 				}
 			}

src/main/java/spoon/reflect/declaration/CtPackage.java

@@ -59,6 +59,8 @@ public interface CtPackage extends CtNamedElement, CtShadowable {
 
 	/**
 	 * Gets the set of included child packages.
+	 * This method might take linear time (regarding the amount of packages in this package).
+	 * For emptiness-checks, {@link #hasPackages()} should be preferred.
 	 */
 	@PropertyGetter(role = SUB_PACKAGE)
 	Set<CtPackage> getPackages();
@@ -91,6 +93,8 @@ public interface CtPackage extends CtNamedElement, CtShadowable {
 
 	/**
 	 * Returns the set of the top-level types in this package.
+	 * This method might take linear time (regarding the amount of types in this package).
+	 * For emptiness-checks, {@link #hasTypes()} should be preferred.
 	 */
 	@PropertyGetter(role = CONTAINED_TYPE)
 	Set<CtType<?>> getTypes();
@@ -161,4 +165,24 @@ public interface CtPackage extends CtNamedElement, CtShadowable {
 	 * @return true if the package contains no types nor any other packages
 	 */
 	boolean isEmpty();
+
+	/**
+	 * Returns true if this package contains any types.
+	 * This method is expected to provide constant-time performance
+	 * and should be preferred over {@link #getTypes()}{@code .isEmpty()}.
+	 *
+	 * @return true if the package contains any types.
+	 * @see #getTypes()
+	 */
+	boolean hasTypes();
+
+	/**
+	 * Returns true if this package contains any sub-packages.
+	 * This method is expected to provide constant-time performance
+	 * and should be preferred over {@link #getPackages()}{@code .isEmpty()}.
+	 *
+	 * @return true if the package contains any sub-packages
+	 * @see #getPackages()
+	 */
+	boolean hasPackages();
 }

src/main/java/spoon/reflect/factory/PackageFactory.java

@@ -182,7 +182,7 @@ public CtPackage get(String qualifiedName) {
 				continue;
 			}
 			lastNonNullPackage = aPackage;
-			if (!aPackage.getTypes().isEmpty()) {
+			if (aPackage.hasTypes()) {
 				packageWithTypes = aPackage;
 				foundPackageCount++;
 			}

src/main/java/spoon/support/reflect/declaration/CtPackageImpl.java

@@ -242,7 +242,17 @@ public boolean hasPackageInfo() {
 
 	@Override
 	public boolean isEmpty() {
-		return getPackages().isEmpty() && getTypes().isEmpty();
+		return !hasPackages() && !hasTypes();
+	}
+
+	@Override
+	public boolean hasTypes() {
+		return !types.isEmpty();
+	}
+
+	@Override
+	public boolean hasPackages() {
+		return !packs.isEmpty();
 	}
 
 	void updateTypeName(CtType<?> newType, String oldName) {

src/main/java/spoon/support/util/internal/ElementNameMap.java

@@ -130,6 +130,11 @@ public T remove(Object key) {
 		return removed;
 	}
 
+	@Override
+	public boolean isEmpty() {
+		return map.isEmpty();
+	}
+
 	@Override
 	public void clear() {
 		if (map.isEmpty()) {