| /* |
| * Copyright (C) 2008 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.launcher3; |
| |
| import android.app.WallpaperManager; |
| import android.content.ComponentName; |
| import android.content.Context; |
| import android.content.Intent; |
| import android.content.SharedPreferences; |
| import android.content.pm.ApplicationInfo; |
| import android.content.pm.PackageInfo; |
| import android.content.pm.PackageManager; |
| import android.content.pm.PackageManager.NameNotFoundException; |
| import android.content.pm.ResolveInfo; |
| import android.content.res.Resources; |
| import android.graphics.Bitmap; |
| import android.graphics.Color; |
| import android.graphics.Matrix; |
| import android.graphics.Paint; |
| import android.graphics.Rect; |
| import android.os.Build; |
| import android.os.Bundle; |
| import android.os.DeadObjectException; |
| import android.os.PowerManager; |
| import android.os.TransactionTooLargeException; |
| import android.text.Spannable; |
| import android.text.SpannableString; |
| import android.text.TextUtils; |
| import android.text.style.TtsSpan; |
| import android.util.DisplayMetrics; |
| import android.util.Log; |
| import android.util.Pair; |
| import android.util.SparseArray; |
| import android.util.TypedValue; |
| import android.view.View; |
| |
| import com.android.launcher3.config.FeatureFlags; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import java.util.Collection; |
| import java.util.HashSet; |
| import java.util.Locale; |
| import java.util.concurrent.Executor; |
| import java.util.concurrent.LinkedBlockingQueue; |
| import java.util.concurrent.ThreadPoolExecutor; |
| import java.util.concurrent.TimeUnit; |
| import java.util.regex.Matcher; |
| import java.util.regex.Pattern; |
| |
| /** |
| * Various utilities shared amongst the Launcher's classes. |
| */ |
| public final class Utilities { |
| |
| private static final String TAG = "Launcher.Utilities"; |
| |
| private static final Pattern sTrimPattern = |
| Pattern.compile("^[\\s|\\p{javaSpaceChar}]*(.*)[\\s|\\p{javaSpaceChar}]*$"); |
| |
| private static final int[] sLoc0 = new int[2]; |
| private static final int[] sLoc1 = new int[2]; |
| private static final float[] sPoint = new float[2]; |
| private static final Matrix sMatrix = new Matrix(); |
| private static final Matrix sInverseMatrix = new Matrix(); |
| |
| public static final boolean ATLEAST_OREO_MR1 = |
| Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1; |
| |
| public static final boolean ATLEAST_OREO = |
| Build.VERSION.SDK_INT >= Build.VERSION_CODES.O; |
| |
| public static final boolean ATLEAST_NOUGAT_MR1 = |
| Build.VERSION.SDK_INT >= Build.VERSION_CODES.N_MR1; |
| |
| public static final boolean ATLEAST_NOUGAT = |
| Build.VERSION.SDK_INT >= Build.VERSION_CODES.N; |
| |
| public static final boolean ATLEAST_MARSHMALLOW = |
| Build.VERSION.SDK_INT >= Build.VERSION_CODES.M; |
| |
| public static final boolean ATLEAST_LOLLIPOP_MR1 = |
| Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1; |
| |
| /** |
| * Indicates if the device has a debug build. Should only be used to store additional info or |
| * add extra logging and not for changing the app behavior. |
| */ |
| public static final boolean IS_DEBUG_DEVICE = Build.TYPE.toLowerCase().contains("debug"); |
| |
| // An intent extra to indicate the horizontal scroll of the wallpaper. |
| public static final String EXTRA_WALLPAPER_OFFSET = "com.android.launcher3.WALLPAPER_OFFSET"; |
| |
| public static final int COLOR_EXTRACTION_JOB_ID = 1; |
| public static final int WALLPAPER_COMPAT_JOB_ID = 2; |
| |
| // These values are same as that in {@link AsyncTask}. |
| private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors(); |
| private static final int CORE_POOL_SIZE = CPU_COUNT + 1; |
| private static final int MAXIMUM_POOL_SIZE = CPU_COUNT * 2 + 1; |
| private static final int KEEP_ALIVE = 1; |
| /** |
| * An {@link Executor} to be used with async task with no limit on the queue size. |
| */ |
| public static final Executor THREAD_POOL_EXECUTOR = new ThreadPoolExecutor( |
| CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE, |
| TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>()); |
| |
| public static final String ALLOW_ROTATION_PREFERENCE_KEY = "pref_allowRotation"; |
| |
| public static boolean isPropertyEnabled(String propertyName) { |
| return Log.isLoggable(propertyName, Log.VERBOSE); |
| } |
| |
| public static boolean isAllowRotationPrefEnabled(Context context) { |
| return getPrefs(context).getBoolean(ALLOW_ROTATION_PREFERENCE_KEY, |
| getAllowRotationDefaultValue(context)); |
| } |
| |
| public static boolean getAllowRotationDefaultValue(Context context) { |
| if (ATLEAST_NOUGAT) { |
| // If the device was scaled, used the original dimensions to determine if rotation |
| // is allowed of not. |
| Resources res = context.getResources(); |
| int originalSmallestWidth = res.getConfiguration().smallestScreenWidthDp |
| * res.getDisplayMetrics().densityDpi / DisplayMetrics.DENSITY_DEVICE_STABLE; |
| return originalSmallestWidth >= 600; |
| } |
| return false; |
| } |
| |
| /** |
| * Given a coordinate relative to the descendant, find the coordinate in a parent view's |
| * coordinates. |
| * |
| * @param descendant The descendant to which the passed coordinate is relative. |
| * @param ancestor The root view to make the coordinates relative to. |
| * @param coord The coordinate that we want mapped. |
| * @param includeRootScroll Whether or not to account for the scroll of the descendant: |
| * sometimes this is relevant as in a child's coordinates within the descendant. |
| * @return The factor by which this descendant is scaled relative to this DragLayer. Caution |
| * this scale factor is assumed to be equal in X and Y, and so if at any point this |
| * assumption fails, we will need to return a pair of scale factors. |
| */ |
| public static float getDescendantCoordRelativeToAncestor( |
| View descendant, View ancestor, int[] coord, boolean includeRootScroll) { |
| sPoint[0] = coord[0]; |
| sPoint[1] = coord[1]; |
| |
| float scale = 1.0f; |
| View v = descendant; |
| while(v != ancestor && v != null) { |
| // For TextViews, scroll has a meaning which relates to the text position |
| // which is very strange... ignore the scroll. |
| if (v != descendant || includeRootScroll) { |
| sPoint[0] -= v.getScrollX(); |
| sPoint[1] -= v.getScrollY(); |
| } |
| |
| v.getMatrix().mapPoints(sPoint); |
| sPoint[0] += v.getLeft(); |
| sPoint[1] += v.getTop(); |
| scale *= v.getScaleX(); |
| |
| v = (View) v.getParent(); |
| } |
| |
| coord[0] = Math.round(sPoint[0]); |
| coord[1] = Math.round(sPoint[1]); |
| return scale; |
| } |
| |
| /** |
| * Inverse of {@link #getDescendantCoordRelativeToAncestor(View, View, int[], boolean)}. |
| */ |
| public static void mapCoordInSelfToDescendant(View descendant, View root, int[] coord) { |
| sMatrix.reset(); |
| View v = descendant; |
| while(v != root) { |
| sMatrix.postTranslate(-v.getScrollX(), -v.getScrollY()); |
| sMatrix.postConcat(v.getMatrix()); |
| sMatrix.postTranslate(v.getLeft(), v.getTop()); |
| v = (View) v.getParent(); |
| } |
| sMatrix.postTranslate(-v.getScrollX(), -v.getScrollY()); |
| sMatrix.invert(sInverseMatrix); |
| |
| sPoint[0] = coord[0]; |
| sPoint[1] = coord[1]; |
| sInverseMatrix.mapPoints(sPoint); |
| coord[0] = Math.round(sPoint[0]); |
| coord[1] = Math.round(sPoint[1]); |
| } |
| |
| /** |
| * Utility method to determine whether the given point, in local coordinates, |
| * is inside the view, where the area of the view is expanded by the slop factor. |
| * This method is called while processing touch-move events to determine if the event |
| * is still within the view. |
| */ |
| public static boolean pointInView(View v, float localX, float localY, float slop) { |
| return localX >= -slop && localY >= -slop && localX < (v.getWidth() + slop) && |
| localY < (v.getHeight() + slop); |
| } |
| |
| public static int[] getCenterDeltaInScreenSpace(View v0, View v1) { |
| v0.getLocationInWindow(sLoc0); |
| v1.getLocationInWindow(sLoc1); |
| |
| sLoc0[0] += (v0.getMeasuredWidth() * v0.getScaleX()) / 2; |
| sLoc0[1] += (v0.getMeasuredHeight() * v0.getScaleY()) / 2; |
| sLoc1[0] += (v1.getMeasuredWidth() * v1.getScaleX()) / 2; |
| sLoc1[1] += (v1.getMeasuredHeight() * v1.getScaleY()) / 2; |
| return new int[] {sLoc1[0] - sLoc0[0], sLoc1[1] - sLoc0[1]}; |
| } |
| |
| public static void scaleRectAboutCenter(Rect r, float scale) { |
| if (scale != 1.0f) { |
| int cx = r.centerX(); |
| int cy = r.centerY(); |
| r.offset(-cx, -cy); |
| |
| r.left = (int) (r.left * scale + 0.5f); |
| r.top = (int) (r.top * scale + 0.5f); |
| r.right = (int) (r.right * scale + 0.5f); |
| r.bottom = (int) (r.bottom * scale + 0.5f); |
| |
| r.offset(cx, cy); |
| } |
| } |
| |
| public static float shrinkRect(Rect r, float scaleX, float scaleY) { |
| float scale = Math.min(Math.min(scaleX, scaleY), 1.0f); |
| if (scale < 1.0f) { |
| int deltaX = (int) (r.width() * (scaleX - scale) * 0.5f); |
| r.left += deltaX; |
| r.right -= deltaX; |
| |
| int deltaY = (int) (r.height() * (scaleY - scale) * 0.5f); |
| r.top += deltaY; |
| r.bottom -= deltaY; |
| } |
| return scale; |
| } |
| |
| public static boolean isSystemApp(Context context, Intent intent) { |
| PackageManager pm = context.getPackageManager(); |
| ComponentName cn = intent.getComponent(); |
| String packageName = null; |
| if (cn == null) { |
| ResolveInfo info = pm.resolveActivity(intent, PackageManager.MATCH_DEFAULT_ONLY); |
| if ((info != null) && (info.activityInfo != null)) { |
| packageName = info.activityInfo.packageName; |
| } |
| } else { |
| packageName = cn.getPackageName(); |
| } |
| if (packageName != null) { |
| try { |
| PackageInfo info = pm.getPackageInfo(packageName, 0); |
| return (info != null) && (info.applicationInfo != null) && |
| ((info.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0); |
| } catch (NameNotFoundException e) { |
| return false; |
| } |
| } else { |
| return false; |
| } |
| } |
| |
| /** |
| * This picks a dominant color, looking for high-saturation, high-value, repeated hues. |
| * @param bitmap The bitmap to scan |
| * @param samples The approximate max number of samples to use. |
| */ |
| public static int findDominantColorByHue(Bitmap bitmap, int samples) { |
| final int height = bitmap.getHeight(); |
| final int width = bitmap.getWidth(); |
| int sampleStride = (int) Math.sqrt((height * width) / samples); |
| if (sampleStride < 1) { |
| sampleStride = 1; |
| } |
| |
| // This is an out-param, for getting the hsv values for an rgb |
| float[] hsv = new float[3]; |
| |
| // First get the best hue, by creating a histogram over 360 hue buckets, |
| // where each pixel contributes a score weighted by saturation, value, and alpha. |
| float[] hueScoreHistogram = new float[360]; |
| float highScore = -1; |
| int bestHue = -1; |
| |
| int[] pixels = new int[samples]; |
| int pixelCount = 0; |
| |
| for (int y = 0; y < height; y += sampleStride) { |
| for (int x = 0; x < width; x += sampleStride) { |
| int argb = bitmap.getPixel(x, y); |
| int alpha = 0xFF & (argb >> 24); |
| if (alpha < 0x80) { |
| // Drop mostly-transparent pixels. |
| continue; |
| } |
| // Remove the alpha channel. |
| int rgb = argb | 0xFF000000; |
| Color.colorToHSV(rgb, hsv); |
| // Bucket colors by the 360 integer hues. |
| int hue = (int) hsv[0]; |
| if (hue < 0 || hue >= hueScoreHistogram.length) { |
| // Defensively avoid array bounds violations. |
| continue; |
| } |
| if (pixelCount < samples) { |
| pixels[pixelCount++] = rgb; |
| } |
| float score = hsv[1] * hsv[2]; |
| hueScoreHistogram[hue] += score; |
| if (hueScoreHistogram[hue] > highScore) { |
| highScore = hueScoreHistogram[hue]; |
| bestHue = hue; |
| } |
| } |
| } |
| |
| SparseArray<Float> rgbScores = new SparseArray<>(); |
| int bestColor = 0xff000000; |
| highScore = -1; |
| // Go back over the RGB colors that match the winning hue, |
| // creating a histogram of weighted s*v scores, for up to 100*100 [s,v] buckets. |
| // The highest-scoring RGB color wins. |
| for (int i = 0; i < pixelCount; i++) { |
| int rgb = pixels[i]; |
| Color.colorToHSV(rgb, hsv); |
| int hue = (int) hsv[0]; |
| if (hue == bestHue) { |
| float s = hsv[1]; |
| float v = hsv[2]; |
| int bucket = (int) (s * 100) + (int) (v * 10000); |
| // Score by cumulative saturation * value. |
| float score = s * v; |
| Float oldTotal = rgbScores.get(bucket); |
| float newTotal = oldTotal == null ? score : oldTotal + score; |
| rgbScores.put(bucket, newTotal); |
| if (newTotal > highScore) { |
| highScore = newTotal; |
| // All the colors in the winning bucket are very similar. Last in wins. |
| bestColor = rgb; |
| } |
| } |
| } |
| return bestColor; |
| } |
| |
| /* |
| * Finds a system apk which had a broadcast receiver listening to a particular action. |
| * @param action intent action used to find the apk |
| * @return a pair of apk package name and the resources. |
| */ |
| static Pair<String, Resources> findSystemApk(String action, PackageManager pm) { |
| final Intent intent = new Intent(action); |
| for (ResolveInfo info : pm.queryBroadcastReceivers(intent, 0)) { |
| if (info.activityInfo != null && |
| (info.activityInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) { |
| final String packageName = info.activityInfo.packageName; |
| try { |
| final Resources res = pm.getResourcesForApplication(packageName); |
| return Pair.create(packageName, res); |
| } catch (NameNotFoundException e) { |
| Log.w(TAG, "Failed to find resources for " + packageName); |
| } |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Compresses the bitmap to a byte array for serialization. |
| */ |
| public static byte[] flattenBitmap(Bitmap bitmap) { |
| // Try go guesstimate how much space the icon will take when serialized |
| // to avoid unnecessary allocations/copies during the write. |
| int size = bitmap.getWidth() * bitmap.getHeight() * 4; |
| ByteArrayOutputStream out = new ByteArrayOutputStream(size); |
| try { |
| bitmap.compress(Bitmap.CompressFormat.PNG, 100, out); |
| out.flush(); |
| out.close(); |
| return out.toByteArray(); |
| } catch (IOException e) { |
| Log.w(TAG, "Could not write bitmap"); |
| return null; |
| } |
| } |
| |
| /** |
| * Trims the string, removing all whitespace at the beginning and end of the string. |
| * Non-breaking whitespaces are also removed. |
| */ |
| public static String trim(CharSequence s) { |
| if (s == null) { |
| return null; |
| } |
| |
| // Just strip any sequence of whitespace or java space characters from the beginning and end |
| Matcher m = sTrimPattern.matcher(s); |
| return m.replaceAll("$1"); |
| } |
| |
| /** |
| * Calculates the height of a given string at a specific text size. |
| */ |
| public static int calculateTextHeight(float textSizePx) { |
| Paint p = new Paint(); |
| p.setTextSize(textSizePx); |
| Paint.FontMetrics fm = p.getFontMetrics(); |
| return (int) Math.ceil(fm.bottom - fm.top); |
| } |
| |
| /** |
| * Convenience println with multiple args. |
| */ |
| public static void println(String key, Object... args) { |
| StringBuilder b = new StringBuilder(); |
| b.append(key); |
| b.append(": "); |
| boolean isFirstArgument = true; |
| for (Object arg : args) { |
| if (isFirstArgument) { |
| isFirstArgument = false; |
| } else { |
| b.append(", "); |
| } |
| b.append(arg); |
| } |
| System.out.println(b.toString()); |
| } |
| |
| public static boolean isRtl(Resources res) { |
| return res.getConfiguration().getLayoutDirection() == View.LAYOUT_DIRECTION_RTL; |
| } |
| |
| /** |
| * Returns true if the intent is a valid launch intent for a launcher activity of an app. |
| * This is used to identify shortcuts which are different from the ones exposed by the |
| * applications' manifest file. |
| * |
| * @param launchIntent The intent that will be launched when the shortcut is clicked. |
| */ |
| public static boolean isLauncherAppTarget(Intent launchIntent) { |
| if (launchIntent != null |
| && Intent.ACTION_MAIN.equals(launchIntent.getAction()) |
| && launchIntent.getComponent() != null |
| && launchIntent.getCategories() != null |
| && launchIntent.getCategories().size() == 1 |
| && launchIntent.hasCategory(Intent.CATEGORY_LAUNCHER) |
| && TextUtils.isEmpty(launchIntent.getDataString())) { |
| // An app target can either have no extra or have ItemInfo.EXTRA_PROFILE. |
| Bundle extras = launchIntent.getExtras(); |
| return extras == null || extras.keySet().isEmpty(); |
| } |
| return false; |
| } |
| |
| public static float dpiFromPx(int size, DisplayMetrics metrics){ |
| float densityRatio = (float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT; |
| return (size / densityRatio); |
| } |
| public static int pxFromDp(float size, DisplayMetrics metrics) { |
| return (int) Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, |
| size, metrics)); |
| } |
| public static int pxFromSp(float size, DisplayMetrics metrics) { |
| return (int) Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, |
| size, metrics)); |
| } |
| |
| public static String createDbSelectionQuery(String columnName, Iterable<?> values) { |
| return String.format(Locale.ENGLISH, "%s IN (%s)", columnName, TextUtils.join(", ", values)); |
| } |
| |
| public static boolean isBootCompleted() { |
| return "1".equals(getSystemProperty("sys.boot_completed", "1")); |
| } |
| |
| public static String getSystemProperty(String property, String defaultValue) { |
| try { |
| Class clazz = Class.forName("android.os.SystemProperties"); |
| Method getter = clazz.getDeclaredMethod("get", String.class); |
| String value = (String) getter.invoke(null, property); |
| if (!TextUtils.isEmpty(value)) { |
| return value; |
| } |
| } catch (Exception e) { |
| Log.d(TAG, "Unable to read system properties"); |
| } |
| return defaultValue; |
| } |
| |
| /** |
| * Ensures that a value is within given bounds. Specifically: |
| * If value is less than lowerBound, return lowerBound; else if value is greater than upperBound, |
| * return upperBound; else return value unchanged. |
| */ |
| public static int boundToRange(int value, int lowerBound, int upperBound) { |
| return Math.max(lowerBound, Math.min(value, upperBound)); |
| } |
| |
| /** |
| * @see #boundToRange(int, int, int). |
| */ |
| public static float boundToRange(float value, float lowerBound, float upperBound) { |
| return Math.max(lowerBound, Math.min(value, upperBound)); |
| } |
| |
| /** |
| * Wraps a message with a TTS span, so that a different message is spoken than |
| * what is getting displayed. |
| * @param msg original message |
| * @param ttsMsg message to be spoken |
| */ |
| public static CharSequence wrapForTts(CharSequence msg, String ttsMsg) { |
| SpannableString spanned = new SpannableString(msg); |
| spanned.setSpan(new TtsSpan.TextBuilder(ttsMsg).build(), |
| 0, spanned.length(), Spannable.SPAN_INCLUSIVE_INCLUSIVE); |
| return spanned; |
| } |
| |
| /** |
| * Replacement for Long.compare() which was added in API level 19. |
| */ |
| public static int longCompare(long lhs, long rhs) { |
| return lhs < rhs ? -1 : (lhs == rhs ? 0 : 1); |
| } |
| |
| public static SharedPreferences getPrefs(Context context) { |
| return context.getSharedPreferences( |
| LauncherFiles.SHARED_PREFERENCES_KEY, Context.MODE_PRIVATE); |
| } |
| |
| public static SharedPreferences getDevicePrefs(Context context) { |
| return context.getSharedPreferences( |
| LauncherFiles.DEVICE_PREFERENCES_KEY, Context.MODE_PRIVATE); |
| } |
| |
| public static boolean isPowerSaverOn(Context context) { |
| PowerManager powerManager = (PowerManager) context.getSystemService(Context.POWER_SERVICE); |
| return powerManager.isPowerSaveMode(); |
| } |
| |
| public static boolean isWallpaperAllowed(Context context) { |
| if (ATLEAST_NOUGAT) { |
| try { |
| WallpaperManager wm = context.getSystemService(WallpaperManager.class); |
| return (Boolean) wm.getClass().getDeclaredMethod("isSetWallpaperAllowed") |
| .invoke(wm); |
| } catch (Exception e) { } |
| } |
| return true; |
| } |
| |
| public static void closeSilently(Closeable c) { |
| if (c != null) { |
| try { |
| c.close(); |
| } catch (IOException e) { |
| if (FeatureFlags.IS_DOGFOOD_BUILD) { |
| Log.d(TAG, "Error closing", e); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Returns true if {@param original} contains all entries defined in {@param updates} and |
| * have the same value. |
| * The comparison uses {@link Object#equals(Object)} to compare the values. |
| */ |
| public static boolean containsAll(Bundle original, Bundle updates) { |
| for (String key : updates.keySet()) { |
| Object value1 = updates.get(key); |
| Object value2 = original.get(key); |
| if (value1 == null) { |
| if (value2 != null) { |
| return false; |
| } |
| } else if (!value1.equals(value2)) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /** Returns whether the collection is null or empty. */ |
| public static boolean isEmpty(Collection c) { |
| return c == null || c.isEmpty(); |
| } |
| |
| public static boolean isBinderSizeError(Exception e) { |
| return e.getCause() instanceof TransactionTooLargeException |
| || e.getCause() instanceof DeadObjectException; |
| } |
| |
| public static <T> T getOverrideObject(Class<T> clazz, Context context, int resId) { |
| String className = context.getString(resId); |
| if (!TextUtils.isEmpty(className)) { |
| try { |
| Class<?> cls = Class.forName(className); |
| return (T) cls.getDeclaredConstructor(Context.class).newInstance(context); |
| } catch (ClassNotFoundException | InstantiationException | IllegalAccessException |
| | ClassCastException | NoSuchMethodException | InvocationTargetException e) { |
| Log.e(TAG, "Bad overriden class", e); |
| } |
| } |
| |
| try { |
| return clazz.newInstance(); |
| } catch (InstantiationException|IllegalAccessException e) { |
| throw new RuntimeException(e); |
| } |
| } |
| |
| /** |
| * Returns a HashSet with a single element. We use this instead of Collections.singleton() |
| * because HashSet ensures all operations, such as remove, are supported. |
| */ |
| public static <T> HashSet<T> singletonHashSet(T elem) { |
| HashSet<T> hashSet = new HashSet<>(1); |
| hashSet.add(elem); |
| return hashSet; |
| } |
| |
| } |