# Subject Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) # Subject ``` class Subject : Serializable ``` |---|------------------------------------------------------------------------------------------------------------| | [kotlin.Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html) || | ↳ | [javax.security.auth.Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#) | A`Subject`represents a grouping of related information for a single entity, such as a person. Such information includes the Subject's identities as well as its security-related attributes (passwords and cryptographic keys, for example). Subjects may potentially have multiple identities. Each identity is represented as a`Principal`within the`Subject`. Principals simply bind names to a`Subject`. For example, a`Subject`that happens to be a person, Alice, might have two Principals: one which binds "Alice Bar", the name on her driver license, to the`Subject`, and another which binds, "999-99-9999", the number on her student identification card, to the`Subject`. Both Principals refer to the same`Subject`even though each has a different name. A`Subject`may also own security-related attributes, which are referred to as credentials. Sensitive credentials that require special protection, such as private cryptographic keys, are stored within a private credential`Set`. Credentials intended to be shared, such as public key certificates or Kerberos server tickets are stored within a public credential`Set`. Different permissions are required to access and modify the different credential Sets. To retrieve all the Principals associated with a`Subject`, invoke the`getPrincipals`method. To retrieve all the public or private credentials belonging to a`Subject`, invoke the`getPublicCredentials`method or`getPrivateCredentials`method, respectively. To modify the returned`Set`of Principals and credentials, use the methods defined in the`Set`class. For example: ```kotlin Subject subject; Principal principal; Object credential; // add a Principal and credential to the Subject subject.getPrincipals().add(principal); subject.getPublicCredentials().add(credential); ``` This`Subject`class implements`Serializable`. While the Principals associated with the`Subject`are serialized, the credentials associated with the`Subject`are not. Note that the`java.security.Principal`class does not implement`Serializable`. Therefore all concrete`Principal`implementations associated with Subjects must implement`Serializable`. ## Summary | Public constructors || |--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---| | [Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#Subject())`()` Create an instance of a`Subject`with an empty`Set`of Principals and empty Sets of public and private credentials. | | [Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#Subject(kotlin.Boolean,%20kotlin.collections.MutableSet,%20kotlin.collections.MutableSet,%20kotlin.collections.MutableSet))`(`readOnly:` `[Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html)`, `principals:` `[MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)!`, `pubCredentials:` `[MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)<*>!`, `privCredentials:` `[MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)<*>!`)` Create an instance of a`Subject`with Principals and credentials. | | Public methods || |------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | staticT | [doAs](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#doAs(javax.security.auth.Subject,%20java.security.PrivilegedAction))`(`subject:` `[Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#)!`, `action:` `[PrivilegedAction](https://developer.android.com/reference/kotlin/java/security/PrivilegedAction.html#)!`)` Perform work as a particular`Subject`. | | staticT | [doAs](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#doAs(javax.security.auth.Subject,%20java.security.PrivilegedExceptionAction))`(`subject:` `[Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#)!`, `action:` `[PrivilegedExceptionAction](https://developer.android.com/reference/kotlin/java/security/PrivilegedExceptionAction.html#)!`)` Perform work as a particular`Subject`. | | staticT | [doAsPrivileged](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#doAsPrivileged(javax.security.auth.Subject,%20java.security.PrivilegedAction,%20java.security.AccessControlContext))`(`subject:` `[Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#)!`, `action:` `[PrivilegedAction](https://developer.android.com/reference/kotlin/java/security/PrivilegedAction.html#)!`, `acc:` `[AccessControlContext](https://developer.android.com/reference/kotlin/java/security/AccessControlContext.html#)!`)` Perform privileged work as a particular`Subject`. | | staticT | [doAsPrivileged](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#doAsPrivileged(javax.security.auth.Subject,%20java.security.PrivilegedExceptionAction,%20java.security.AccessControlContext))`(`subject:` `[Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#)!`, `action:` `[PrivilegedExceptionAction](https://developer.android.com/reference/kotlin/java/security/PrivilegedExceptionAction.html#)!`, `acc:` `[AccessControlContext](https://developer.android.com/reference/kotlin/java/security/AccessControlContext.html#)!`)` Perform privileged work as a particular`Subject`. | | [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | [equals](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#equals(kotlin.Any))`(`other:` `[Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html)?`)` Compares the specified Object with this`Subject`for equality. | | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)\<[Principal](https://developer.android.com/reference/kotlin/java/security/Principal.html#)!\>! | [getPrincipals](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#getPrincipals())`()` Return the`Set`of Principals associated with this`Subject`. | | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)\! | [getPrincipals](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#getPrincipals(java.lang.Class))`(`c:` `[Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)!`)` Return a`Set`of Principals associated with this`Subject`that are instances or subclasses of the specified`Class`. | | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)\<[Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html)!\>! | [getPrivateCredentials](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#getPrivateCredentials())`()` Return the`Set`of private credentials held by this`Subject`. | | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)\! | [getPrivateCredentials](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#getPrivateCredentials(java.lang.Class))`(`c:` `[Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)!`)` Return a`Set`of private credentials associated with this`Subject`that are instances or subclasses of the specified`Class`. | | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)\<[Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html)!\>! | [getPublicCredentials](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#getPublicCredentials())`()` Return the`Set`of public credentials held by this`Subject`. | | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)\! | [getPublicCredentials](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#getPublicCredentials(java.lang.Class))`(`c:` `[Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)!`)` Return a`Set`of public credentials associated with this`Subject`that are instances or subclasses of the specified`Class`. | | static[Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#)! | [getSubject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#getSubject(java.security.AccessControlContext))`(`acc:` `[AccessControlContext](https://developer.android.com/reference/kotlin/java/security/AccessControlContext.html#)!`)` Get the`Subject`associated with the provided`AccessControlContext`. | | [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html) | [hashCode](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#hashCode())`()` Returns a hashcode for this`Subject`. | | [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | [isReadOnly](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#isReadOnly())`()` Query whether this`Subject`is read-only. | | [Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [setReadOnly](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#setReadOnly())`()` Set this`Subject`to be read-only. | | [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html) | [toString](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#toString())`()` Return the String representation of this`Subject`. | ## Public constructors ### Subject Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` Subject() ``` Create an instance of a`Subject`with an empty`Set`of Principals and empty Sets of public and private credentials. The newly constructed Sets check whether this`Subject`has been set read-only before permitting subsequent modifications. The newly created Sets also prevent illegal modifications by ensuring that callers have sufficient permissions. To modify the Principals Set, the caller must have`AuthPermission("modifyPrincipals")`. To modify the public credential Set, the caller must have`AuthPermission("modifyPublicCredentials")`. To modify the private credential Set, the caller must have`AuthPermission("modifyPrivateCredentials")`. ### Subject Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` Subject(     readOnly: Boolean,     principals: MutableSet!,     pubCredentials: MutableSet<*>!,     privCredentials: MutableSet<*>!) ``` Create an instance of a`Subject`with Principals and credentials. The Principals and credentials from the specified Sets are copied into newly constructed Sets. These newly created Sets check whether this`Subject`has been set read-only before permitting subsequent modifications. The newly created Sets also prevent illegal modifications by ensuring that callers have sufficient permissions. To modify the Principals Set, the caller must have`AuthPermission("modifyPrincipals")`. To modify the public credential Set, the caller must have`AuthPermission("modifyPublicCredentials")`. To modify the private credential Set, the caller must have`AuthPermission("modifyPrivateCredentials")`.
| Parameters || |-------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `readOnly` | [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html):true if the`Subject`is to be read-only, and false otherwise.
| | `principals` | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)\!:the`Set`of Principals to be associated with this`Subject`.
| | `pubCredentials` | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)\<\*\>!:the`Set`of public credentials to be associated with this`Subject`.
| | `privCredentials` | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)\<\*\>!:the`Set`of private credentials to be associated with this`Subject`. | | Exceptions || |----------------------------------|------------------------------------------------------------------------------| | `java.lang.NullPointerException` | if the specified`principals`,`pubCredentials`, or`privCredentials`are`null`. | ## Public methods ### doAs Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` static fun doAs(     subject: Subject!,     action: PrivilegedAction! ): T ``` Perform work as a particular`Subject`. This method first retrieves the current Thread's`AccessControlContext`via`AccessController.getContext`, and then instantiates a new`AccessControlContext`using the retrieved context along with a new`SubjectDomainCombiner`(constructed using the provided`Subject`). Finally, this method invokes`AccessController.doPrivileged`, passing it the provided`PrivilegedAction`, as well as the newly constructed`AccessControlContext`.
| Parameters || |-----------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `subject` | [Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#)!:the`Subject`that the specified`action`will run as. This parameter may be`null`.
| | `` | the type of the value returned by the PrivilegedAction's`run`method. | | `action` | [PrivilegedAction](https://developer.android.com/reference/kotlin/java/security/PrivilegedAction.html#)\!:the code to be run as the specified`Subject`.
| | Return || |---|----------------------------------------------------------| | T | the value returned by the PrivilegedAction's`run`method. | | Exceptions || |----------------------------------|---------------------------------------------------------------| | `java.lang.NullPointerException` | if the`PrivilegedAction`is`null`.
| | `java.lang.SecurityException` | if the caller does not have permission to invoke this method. | ### doAs Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` static fun doAs(     subject: Subject!,     action: PrivilegedExceptionAction! ): T ``` Perform work as a particular`Subject`. This method first retrieves the current Thread's`AccessControlContext`via`AccessController.getContext`, and then instantiates a new`AccessControlContext`using the retrieved context along with a new`SubjectDomainCombiner`(constructed using the provided`Subject`). Finally, this method invokes`AccessController.doPrivileged`, passing it the provided`PrivilegedExceptionAction`, as well as the newly constructed`AccessControlContext`.
| Parameters || |-----------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `subject` | [Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#)!:the`Subject`that the specified`action`will run as. This parameter may be`null`.
| | `` | the type of the value returned by the PrivilegedExceptionAction's`run`method. | | `action` | [PrivilegedExceptionAction](https://developer.android.com/reference/kotlin/java/security/PrivilegedExceptionAction.html#)\!:the code to be run as the specified`Subject`.
| | Return || |---|-------------------------------------------------------------------| | T | the value returned by the PrivilegedExceptionAction's`run`method. | | Exceptions || |-------------------------------------------|--------------------------------------------------------------------------------| | `java.security.PrivilegedActionException` | if the`PrivilegedExceptionAction.run`method throws a checked exception.
| | `java.lang.NullPointerException` | if the specified`PrivilegedExceptionAction`is`null`.
| | `java.lang.SecurityException` | if the caller does not have permission to invoke this method. | ### doAsPrivileged Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` static fun doAsPrivileged(     subject: Subject!,     action: PrivilegedAction!,     acc: AccessControlContext! ): T ``` Perform privileged work as a particular`Subject`. This method behaves exactly as`Subject.doAs`, except that instead of retrieving the current Thread's`AccessControlContext`, it uses the provided`AccessControlContext`. If the provided`AccessControlContext`is`null`, this method instantiates a new`AccessControlContext`with an empty collection of ProtectionDomains.
| Parameters || |-----------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `subject` | [Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#)!:the`Subject`that the specified`action`will run as. This parameter may be`null`.
| | `` | the type of the value returned by the PrivilegedAction's`run`method. | | `action` | [PrivilegedAction](https://developer.android.com/reference/kotlin/java/security/PrivilegedAction.html#)\!:the code to be run as the specified`Subject`.
| | `acc` | [AccessControlContext](https://developer.android.com/reference/kotlin/java/security/AccessControlContext.html#)!:the`AccessControlContext`to be tied to the specified*subject* and*action* .
| | Return || |---|----------------------------------------------------------| | T | the value returned by the PrivilegedAction's`run`method. | | Exceptions || |----------------------------------|---------------------------------------------------------------| | `java.lang.NullPointerException` | if the`PrivilegedAction`is`null`.
| | `java.lang.SecurityException` | if the caller does not have permission to invoke this method. | ### doAsPrivileged Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` static fun doAsPrivileged(     subject: Subject!,     action: PrivilegedExceptionAction!,     acc: AccessControlContext! ): T ``` Perform privileged work as a particular`Subject`. This method behaves exactly as`Subject.doAs`, except that instead of retrieving the current Thread's`AccessControlContext`, it uses the provided`AccessControlContext`. If the provided`AccessControlContext`is`null`, this method instantiates a new`AccessControlContext`with an empty collection of ProtectionDomains.
| Parameters || |-----------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `subject` | [Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#)!:the`Subject`that the specified`action`will run as. This parameter may be`null`.
| | `` | the type of the value returned by the PrivilegedExceptionAction's`run`method. | | `action` | [PrivilegedExceptionAction](https://developer.android.com/reference/kotlin/java/security/PrivilegedExceptionAction.html#)\!:the code to be run as the specified`Subject`.
| | `acc` | [AccessControlContext](https://developer.android.com/reference/kotlin/java/security/AccessControlContext.html#)!:the`AccessControlContext`to be tied to the specified*subject* and*action* .
| | Return || |---|-------------------------------------------------------------------| | T | the value returned by the PrivilegedExceptionAction's`run`method. | | Exceptions || |-------------------------------------------|--------------------------------------------------------------------------------| | `java.security.PrivilegedActionException` | if the`PrivilegedExceptionAction.run`method throws a checked exception.
| | `java.lang.NullPointerException` | if the specified`PrivilegedExceptionAction`is`null`.
| | `java.lang.SecurityException` | if the caller does not have permission to invoke this method. | ### equals Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun equals(other: Any?): Boolean ``` Compares the specified Object with this`Subject`for equality. Returns true if the given object is also a Subject and the two`Subject`instances are equivalent. More formally, two`Subject`instances are equal if their`Principal`and`Credential`Sets are equal.
| Parameters || |-------|--------------------------------------------------------| | `obj` | the reference object with which to compare. | | `o` | Object to be compared for equality with this`Subject`. | | Return || |------------------------------------------------------------------------------------|---------------------------------------------------------| | [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | true if the specified Object is equal to this`Subject`. | | Exceptions || |-------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `java.lang.SecurityException` | if the caller does not have permission to access the private credentials for this`Subject`, or if the caller does not have permission to access the private credentials for the provided`Subject`. | ### getPrincipals Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun getPrincipals(): MutableSet! ``` Return the`Set`of Principals associated with this`Subject`. Each`Principal`represents an identity for this`Subject`. The returned`Set`is backed by this Subject's internal`Principal``Set`. Any modification to the returned`Set`affects the internal`Principal``Set`as well.
| Return || |----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------| | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)<[Principal](https://developer.android.com/reference/kotlin/java/security/Principal.html#)!>! | The`Set`of Principals associated with this`Subject`. | ### getPrincipals Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun getPrincipals(c: Class!): MutableSet! ``` Return a`Set`of Principals associated with this`Subject`that are instances or subclasses of the specified`Class`. The returned`Set`is not backed by this Subject's internal`Principal``Set`. A new`Set`is created and returned for each method invocation. Modifications to the returned`Set`will not affect the internal`Principal``Set`.
| Parameters || |-------|---------------------------------------------------------------------------------------------------------------------------------------------------------| | `` | the type of the class modeled by`c` | | `c` | [Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)\!:the returned`Set`of Principals will all be instances of this class. | | Return || |-----------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------| | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)! | a`Set`of Principals that are instances of the specified`Class`. | | Exceptions || |----------------------------------|----------------------------------| | `java.lang.NullPointerException` | if the specified`Class`is`null`. | ### getPrivateCredentials Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun getPrivateCredentials(): MutableSet! ``` Return the`Set`of private credentials held by this`Subject`. The returned`Set`is backed by this Subject's internal private Credential`Set`. Any modification to the returned`Set`affects the internal private Credential`Set`as well. A caller requires permissions to access the Credentials in the returned`Set`, or to modify the`Set`itself. A`SecurityException`is thrown if the caller does not have the proper permissions. While iterating through the`Set`, a`SecurityException`is thrown if the caller does not have permission to access a particular Credential. The`Iterator`is nevertheless advanced to next element in the`Set`.
| Return || |-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------| | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)<[Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html)!>! | A`Set`of private credentials held by this`Subject`. | ### getPrivateCredentials Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun getPrivateCredentials(c: Class!): MutableSet! ``` Return a`Set`of private credentials associated with this`Subject`that are instances or subclasses of the specified`Class`. The caller must have permission to access all of the requested Credentials, or a`SecurityException`will be thrown. The returned`Set`is not backed by this Subject's internal private Credential`Set`. A new`Set`is created and returned for each method invocation. Modifications to the returned`Set`will not affect the internal private Credential`Set`.
| Parameters || |-------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `` | the type of the class modeled by`c` | | `c` | [Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)\!:the returned`Set`of private credentials will all be instances of this class. | | Return || |-----------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------| | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)! | a`Set`of private credentials that are instances of the specified`Class`. | | Exceptions || |----------------------------------|----------------------------------| | `java.lang.NullPointerException` | if the specified`Class`is`null`. | ### getPublicCredentials Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun getPublicCredentials(): MutableSet! ``` Return the`Set`of public credentials held by this`Subject`. The returned`Set`is backed by this Subject's internal public Credential`Set`. Any modification to the returned`Set`affects the internal public Credential`Set`as well.
| Return || |-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------| | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)<[Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html)!>! | A`Set`of public credentials held by this`Subject`. | ### getPublicCredentials Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun getPublicCredentials(c: Class!): MutableSet! ``` Return a`Set`of public credentials associated with this`Subject`that are instances or subclasses of the specified`Class`. The returned`Set`is not backed by this Subject's internal public Credential`Set`. A new`Set`is created and returned for each method invocation. Modifications to the returned`Set`will not affect the internal public Credential`Set`.
| Parameters || |-------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------| | `` | the type of the class modeled by`c` | | `c` | [Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)\!:the returned`Set`of public credentials will all be instances of this class. | | Return || |-----------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------| | [MutableSet](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/index.html)! | a`Set`of public credentials that are instances of the specified`Class`. | | Exceptions || |----------------------------------|----------------------------------| | `java.lang.NullPointerException` | if the specified`Class`is`null`. | ### getSubject Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` static fun getSubject(acc: AccessControlContext!): Subject! ``` Get the`Subject`associated with the provided`AccessControlContext`. The`AccessControlContext`may contain many Subjects (from nested`doAs`calls). In this situation, the most recent`Subject`associated with the`AccessControlContext`is returned.
| Parameters || |-------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `acc` | [AccessControlContext](https://developer.android.com/reference/kotlin/java/security/AccessControlContext.html#)!:the`AccessControlContext`from which to retrieve the`Subject`. | | Return || |-----------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------| | [Subject](https://developer.android.com/reference/kotlin/javax/security/auth/Subject#)! | the`Subject`associated with the provided`AccessControlContext`, or`null`if no`Subject`is associated with the provided`AccessControlContext`. | | Exceptions || |----------------------------------|--------------------------------------------------------------------| | `java.lang.SecurityException` | if the caller does not have permission to get the`Subject`.
| | `java.lang.NullPointerException` | if the provided`AccessControlContext`is`null`. | ### hashCode Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun hashCode(): Int ``` Returns a hashcode for this`Subject`.
| Return || |----------------------------------------------------------------------------|-------------------------------| | [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html) | a hashcode for this`Subject`. | | Exceptions || |-------------------------------|--------------------------------------------------------------------------------------| | `java.lang.SecurityException` | if the caller does not have permission to access this Subject's private credentials. | ### isReadOnly Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun isReadOnly(): Boolean ``` Query whether this`Subject`is read-only.
| Return || |------------------------------------------------------------------------------------|-----------------------------------------------------| | [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | true if this`Subject`is read-only, false otherwise. | ### setReadOnly Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun setReadOnly(): Unit ``` Set this`Subject`to be read-only. Modifications (additions and removals) to this Subject's`Principal``Set`and credential Sets will be disallowed. The`destroy`operation on this Subject's credentials will still be permitted. Subsequent attempts to modify the Subject's`Principal`and credential Sets will result in an`IllegalStateException`being thrown. Also, once a`Subject`is read-only, it can not be reset to being writable again.
| Exceptions || |-------------------------------|-----------------------------------------------------------------------------| | `java.lang.SecurityException` | if the caller does not have permission to set this`Subject`to be read-only. | ### toString Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` fun toString(): String ``` Return the String representation of this`Subject`.
| Return || |----------------------------------------------------------------------------------|---------------------------------------------| | [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html) | the String representation of this`Subject`. |