Merge "Code cleanup"

1 files changed, 58 insertions, 182 deletions

diff --git a/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java b/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java
index 7ff7827..8170835 100644
--- a/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java
+++ b/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java
@@ -100,6 +100,7 @@ import com.android.internal.R;
 import com.android.internal.os.storage.ExternalStorageFormatter;
 import com.android.internal.util.FastXmlSerializer;
 import com.android.internal.util.JournaledFile;
+import com.android.internal.util.Preconditions;
 import com.android.internal.util.XmlUtils;
 import com.android.internal.widget.LockPatternUtils;
 import com.android.server.LocalServices;
@@ -1920,13 +1921,11 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         validateQualityConstant(quality);
 
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_LIMIT_PASSWORD);
             if (ap.passwordQuality != quality) {
@@ -1969,11 +1968,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_LIMIT_PASSWORD);
             if (ap.minimumPasswordLength != length) {
@@ -2016,11 +2013,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_LIMIT_PASSWORD);
             if (ap.passwordHistoryLength != length) {
@@ -2063,14 +2058,10 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
+        Preconditions.checkArgumentNonnegative(timeout, "Timeout must be >= 0 ms");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
-            if (timeout < 0) {
-                throw new IllegalArgumentException("Timeout must be >= 0 ms");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_EXPIRE_PASSWORD);
             // Calling this API automatically bumps the expiration date
@@ -2232,11 +2223,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_LIMIT_PASSWORD);
             if (ap.minimumPasswordUpperCase != length) {
@@ -2276,11 +2265,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
     }
 
     public void setPasswordMinimumLowerCase(ComponentName who, int length) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_LIMIT_PASSWORD);
             if (ap.minimumPasswordLowerCase != length) {
@@ -2323,11 +2310,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_LIMIT_PASSWORD);
             if (ap.minimumPasswordLetters != length) {
@@ -2370,11 +2355,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_LIMIT_PASSWORD);
             if (ap.minimumPasswordNumeric != length) {
@@ -2417,11 +2400,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_LIMIT_PASSWORD);
             if (ap.minimumPasswordSymbols != length) {
@@ -2464,11 +2445,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_LIMIT_PASSWORD);
             if (ap.minimumPasswordNonLetter != length) {
@@ -2561,11 +2540,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             // This API can only be called by an active device admin,
             // so try to retrieve it to check that the caller is one.
             getActiveAdminForCallerLocked(who,
@@ -2772,11 +2749,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_FORCE_LOCK);
             if (ap.maximumTimeToUnlock != timeMs) {
@@ -2955,9 +2930,7 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public boolean installKeyPair(ComponentName who, byte[] privKey, byte[] cert, String alias) {
-        if (who == null) {
-            throw new NullPointerException("ComponentName is null");
-        }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
         }
@@ -3297,9 +3270,7 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
             return null;
         }
         synchronized(this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
+            Preconditions.checkNotNull(who, "ComponentName is null");
 
             // Only check if owner has set global proxy. We don't allow other users to set it.
             DevicePolicyData policy = getUserData(UserHandle.USER_OWNER);
@@ -3435,12 +3406,10 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return DevicePolicyManager.ENCRYPTION_STATUS_UNSUPPORTED;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
             // Check for permissions
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             // Only owner can set storage encryption
             if (userHandle != UserHandle.USER_OWNER
                     || UserHandle.getCallingUserId() != UserHandle.USER_OWNER) {
@@ -3571,11 +3540,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
             if (ap.disableScreenCapture != disabled) {
@@ -3630,11 +3597,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin admin = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_DEVICE_OWNER);
             if (admin.requireAutoTime != required) {
@@ -3682,11 +3647,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_DISABLE_CAMERA);
             if (ap.disableCamera != disabled) {
@@ -3731,12 +3694,10 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         enforceNotManagedProfile(userHandle, "disable keyguard features");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_DISABLE_KEYGUARD_FEATURES);
             if (ap.disabledKeyguardFeatures != which) {
@@ -3880,9 +3841,7 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public void clearDeviceOwner(String packageName) {
-        if (packageName == null) {
-            throw new NullPointerException("packageName is null");
-        }
+        Preconditions.checkNotNull(packageName, "packageName is null");
         try {
             int uid = mContext.getPackageManager().getPackageUid(packageName, 0);
             if (uid != Binder.getCallingUid()) {
@@ -4007,12 +3966,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
         synchronized (this) {
-            // Check for permissions
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             // Check if this is the profile owner who is calling
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
             int userId = UserHandle.getCallingUserId();
@@ -4034,12 +3990,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public void setProfileName(ComponentName who, String profileName) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         int userId = UserHandle.getCallingUserId();
-
-        if (who == null) {
-            throw new NullPointerException("ComponentName is null");
-        }
-
         // Check if this is the profile owner (includes device owner).
         getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
@@ -4215,12 +4167,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
     @Override
     public void addPersistentPreferredActivity(ComponentName who, IntentFilter filter,
             ComponentName activity) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
-
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             IPackageManager pm = AppGlobals.getPackageManager();
@@ -4237,12 +4186,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public void clearPackagePersistentPreferredActivities(ComponentName who, String packageName) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userHandle = UserHandle.getCallingUserId();
-
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             IPackageManager pm = AppGlobals.getPackageManager();
@@ -4259,12 +4205,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public void setApplicationRestrictions(ComponentName who, String packageName, Bundle settings) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final UserHandle userHandle = new UserHandle(UserHandle.getCallingUserId());
-
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             long id = Binder.clearCallingIdentity();
@@ -4281,15 +4224,11 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(admin, "admin is null");
+        Preconditions.checkNotNull(agent, "agent is null");
         final int userHandle = UserHandle.getCallingUserId();
         enforceNotManagedProfile(userHandle, "set trust agent configuration");
         synchronized (this) {
-            if (admin == null) {
-                throw new NullPointerException("admin is null");
-            }
-            if (agent == null) {
-                throw new NullPointerException("agent is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(admin,
                     DeviceAdminInfo.USES_POLICY_DISABLE_KEYGUARD_FEATURES);
             ap.trustAgentInfos.put(agent.flattenToString(), new TrustAgentInfo(args));
@@ -4303,10 +4242,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return null;
         }
+        Preconditions.checkNotNull(agent, "agent null");
         enforceCrossUserPermission(userHandle);
-        if (agent == null) {
-            throw new NullPointerException("agent is null");
-        }
 
         synchronized (this) {
             final String componentName = agent.flattenToString();
@@ -4359,10 +4296,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public void setRestrictionsProvider(ComponentName who, ComponentName permissionProvider) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             int userHandle = UserHandle.getCallingUserId();
@@ -4384,11 +4319,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
     }
 
     public void addCrossProfileIntentFilter(ComponentName who, IntentFilter filter, int flags) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         int callingUserId = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             IPackageManager pm = AppGlobals.getPackageManager();
@@ -4411,11 +4344,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
     }
 
     public void clearCrossProfileIntentFilters(ComponentName who) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         int callingUserId = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
             IPackageManager pm = AppGlobals.getPackageManager();
             long id = Binder.clearCallingIdentity();
@@ -4485,9 +4416,7 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return false;
         }
-        if (who == null) {
-            throw new NullPointerException("ComponentName is null");
-        }
+        Preconditions.checkNotNull(who, "ComponentName is null");
 
         if (packageList != null) {
             int userId = UserHandle.getCallingUserId();
@@ -4532,10 +4461,7 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return null;
         }
-
-        if (who == null) {
-            throw new NullPointerException("ComponentName is null");
-        }
+        Preconditions.checkNotNull(who, "ComponentName is null");
 
         synchronized (this) {
             ActiveAdmin admin = getActiveAdminForCallerLocked(who,
@@ -4640,9 +4566,7 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return false;
         }
-        if (who == null) {
-            throw new NullPointerException("ComponentName is null");
-        }
+        Preconditions.checkNotNull(who, "ComponentName is null");
 
         // TODO When InputMethodManager supports per user calls remove
         //      this restriction.
@@ -4685,10 +4609,7 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return null;
         }
-
-        if (who == null) {
-            throw new NullPointerException("ComponentName is null");
-        }
+        Preconditions.checkNotNull(who, "ComponentName is null");
 
         synchronized (this) {
             ActiveAdmin admin = getActiveAdminForCallerLocked(who,
@@ -4761,10 +4682,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public UserHandle createUser(ComponentName who, String name) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_DEVICE_OWNER);
 
             long id = Binder.clearCallingIdentity();
@@ -4815,10 +4734,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public boolean removeUser(ComponentName who, UserHandle userHandle) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_DEVICE_OWNER);
 
             long id = Binder.clearCallingIdentity();
@@ -4832,10 +4749,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public boolean switchUser(ComponentName who, UserHandle userHandle) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_DEVICE_OWNER);
 
             long id = Binder.clearCallingIdentity();
@@ -4856,12 +4771,10 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public Bundle getApplicationRestrictions(ComponentName who, String packageName) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final UserHandle userHandle = new UserHandle(UserHandle.getCallingUserId());
 
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             long id = Binder.clearCallingIdentity();
@@ -4875,12 +4788,10 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public void setUserRestriction(ComponentName who, String key, boolean enabled) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final UserHandle user = new UserHandle(UserHandle.getCallingUserId());
         final int userHandle = user.getIdentifier();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin activeAdmin =
                     getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
             boolean isDeviceOwner = isDeviceOwner(activeAdmin.info.getPackageName());
@@ -4982,11 +4893,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
     @Override
     public boolean setApplicationHidden(ComponentName who, String packageName,
             boolean hidden) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         int callingUserId = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             long id = Binder.clearCallingIdentity();
@@ -5005,11 +4914,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public boolean isApplicationHidden(ComponentName who, String packageName) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         int callingUserId = UserHandle.getCallingUserId();
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             long id = Binder.clearCallingIdentity();
@@ -5028,11 +4935,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public void enableSystemApp(ComponentName who, String packageName) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
-
             // This API can only be called by an active device admin,
             // so try to retrieve it to check that the caller is one.
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
@@ -5073,11 +4977,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public int enableSystemAppWithIntent(ComponentName who, Intent intent) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
-
             // This API can only be called by an active device admin,
             // so try to retrieve it to check that the caller is one.
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
@@ -5144,10 +5045,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin ap = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
             if (disabled) {
@@ -5185,12 +5084,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
     @Override
     public void setUninstallBlocked(ComponentName who, String packageName,
             boolean uninstallBlocked) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         final int userId = UserHandle.getCallingUserId();
-
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             long id = Binder.clearCallingIdentity();
@@ -5237,10 +5133,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return;
         }
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin admin = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
             if (admin.disableCallerId != disabled) {
@@ -5255,12 +5149,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         if (!mHasFeature) {
             return false;
         }
-
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
-
             ActiveAdmin admin = getActiveAdminForCallerLocked(who,
                     DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
             return admin.disableCallerId;
@@ -5281,13 +5171,11 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
      * Sets which packages may enter lock task mode.
      *
      * This function can only be called by the device owner.
-     * @param components The list of components allowed to enter lock task mode.
+     * @param packages The list of packages allowed to enter lock task mode.
      */
     public void setLockTaskPackages(ComponentName who, String[] packages) throws SecurityException {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_DEVICE_OWNER);
 
             int userHandle = Binder.getCallingUserHandle().getIdentifier();
@@ -5309,15 +5197,13 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
      * This function returns the list of components allowed to start the task lock mode.
      */
     public String[] getLockTaskPackages(ComponentName who) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_DEVICE_OWNER);
 
             int userHandle = Binder.getCallingUserHandle().getIdentifier();
             DevicePolicyData policy = getUserData(userHandle);
-            return policy.mLockTaskPackages.toArray(new String[0]);
+            return policy.mLockTaskPackages.toArray(new String[policy.mLockTaskPackages.size()]);
         }
     }
 
@@ -5373,11 +5259,9 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
     @Override
     public void setGlobalSetting(ComponentName who, String setting, String value) {
         final ContentResolver contentResolver = mContext.getContentResolver();
+        Preconditions.checkNotNull(who, "ComponentName is null");
 
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_DEVICE_OWNER);
 
             if (!GLOBAL_SETTINGS_WHITELIST.contains(setting)) {
@@ -5396,13 +5280,11 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public void setSecureSetting(ComponentName who, String setting, String value) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         int callingUserId = UserHandle.getCallingUserId();
         final ContentResolver contentResolver = mContext.getContentResolver();
 
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             ActiveAdmin activeAdmin =
                     getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
@@ -5427,10 +5309,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public void setMasterVolumeMuted(ComponentName who, boolean on) {
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             IAudioService iAudioService = IAudioService.Stub.asInterface(
@@ -5447,12 +5327,8 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
 
     @Override
     public boolean isMasterVolumeMuted(ComponentName who) {
-        final ContentResolver contentResolver = mContext.getContentResolver();
-
+        Preconditions.checkNotNull(who, "ComponentName is null");
         synchronized (this) {
-            if (who == null) {
-                throw new NullPointerException("ComponentName is null");
-            }
             getActiveAdminForCallerLocked(who, DeviceAdminInfo.USES_POLICY_PROFILE_OWNER);
 
             AudioManager audioManager =