# Wrapper Added in[API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) # Wrapper ``` interface Wrapper ``` |--------------------------------------------------------------------------------------| | [java.sql.Wrapper](https://developer.android.com/reference/kotlin/java/sql/Wrapper#) | 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| Known Direct Subclasses [Connection](https://developer.android.com/reference/kotlin/java/sql/Connection),[DataSource](https://developer.android.com/reference/kotlin/javax/sql/DataSource.html#),[DatabaseMetaData](https://developer.android.com/reference/kotlin/java/sql/DatabaseMetaData),[ParameterMetaData](https://developer.android.com/reference/kotlin/java/sql/ParameterMetaData),[ResultSet](https://developer.android.com/reference/kotlin/java/sql/ResultSet),[ResultSetMetaData](https://developer.android.com/reference/kotlin/java/sql/ResultSetMetaData),[Statement](https://developer.android.com/reference/kotlin/java/sql/Statement) |------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------| | [Connection](https://developer.android.com/reference/kotlin/java/sql/Connection) | A connection (session) with a specific database. | | [DataSource](https://developer.android.com/reference/kotlin/javax/sql/DataSource.html#) | A factory for connections to the physical data source that this`DataSource`object represents. | | [DatabaseMetaData](https://developer.android.com/reference/kotlin/java/sql/DatabaseMetaData) | Comprehensive information about the database as a whole. | | [ParameterMetaData](https://developer.android.com/reference/kotlin/java/sql/ParameterMetaData) | An object that can be used to get information about the types and properties for each parameter marker in a`PreparedStatement`object. | | [ResultSet](https://developer.android.com/reference/kotlin/java/sql/ResultSet) | A table of data representing a database result set, which is usually generated by executing a statement that queries the database. | | [ResultSetMetaData](https://developer.android.com/reference/kotlin/java/sql/ResultSetMetaData) | An object that can be used to get information about the types and properties of the columns in a`ResultSet`object. | | [Statement](https://developer.android.com/reference/kotlin/java/sql/Statement) | The object used for executing a static SQL statement and returning the results it produces. | | 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| Known Indirect Subclasses [CallableStatement](https://developer.android.com/reference/kotlin/java/sql/CallableStatement),[PreparedStatement](https://developer.android.com/reference/kotlin/java/sql/PreparedStatement),[RowSet](https://developer.android.com/reference/kotlin/javax/sql/RowSet.html#),[RowSetMetaData](https://developer.android.com/reference/kotlin/javax/sql/RowSetMetaData.html#) |-------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------| | [CallableStatement](https://developer.android.com/reference/kotlin/java/sql/CallableStatement) | The interface used to execute SQL stored procedures. | | [PreparedStatement](https://developer.android.com/reference/kotlin/java/sql/PreparedStatement) | An object that represents a precompiled SQL statement. | | [RowSet](https://developer.android.com/reference/kotlin/javax/sql/RowSet.html#) | The interface that adds support to the JDBC API for the JavaBeansTM component model. | | [RowSetMetaData](https://developer.android.com/reference/kotlin/javax/sql/RowSetMetaData.html#) | An object that contains information about the columns in a`RowSet`object. | | Interface for JDBC classes which provide the ability to retrieve the delegate instance when the instance in question is in fact a proxy class. The wrapper pattern is employed by many JDBC driver implementations to provide extensions beyond the traditional JDBC API that are specific to a data source. Developers may wish to gain access to these resources that are wrapped (the delegates) as proxy class instances representing the the actual resources. This interface describes a standard mechanism to access these wrapped resources represented by their proxy, to permit direct access to the resource delegates. ## Summary | Public methods || |--------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | abstract[Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | [isWrapperFor](https://developer.android.com/reference/kotlin/java/sql/Wrapper#isWrapperFor(java.lang.Class))`(`iface:` `[Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)<*>!`)` Returns true if this either implements the interface argument or is directly or indirectly a wrapper for an object that does. | | abstractT | [unwrap](https://developer.android.com/reference/kotlin/java/sql/Wrapper#unwrap(java.lang.Class))`(`iface:` `[Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)!`)` Returns an object that implements the given interface to allow access to non-standard methods, or standard methods not exposed by the proxy. | ## Public methods ### isWrapperFor Added in[API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` abstract fun isWrapperFor(iface: Class<*>!): Boolean ``` Returns true if this either implements the interface argument or is directly or indirectly a wrapper for an object that does. Returns false otherwise. If this implements the interface then return true, else if this is a wrapper then return the result of recursively calling`isWrapperFor`on the wrapped object. If this does not implement the interface and is not a wrapper, return false. This method should be implemented as a low-cost operation compared to`unwrap`so that callers can use this method to avoid expensive`unwrap`calls that may fail. If this method returns true then calling`unwrap`with the same argument should succeed. | Parameters || |---------|---------------------------------------------------------------------------------------------------------------------| | `iface` | [Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)\<\*\>!:a Class defining an interface. | | Return || |------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------| | [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | true if this implements the interface or directly or indirectly wraps an object that does. | | Exceptions || |-------------------------|--------------------------------------------------------------------------------------------------------| | `java.sql.SQLException` | if an error occurs while determining whether this is a wrapper for an object with the given interface. | ### unwrap Added in[API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` abstract fun unwrap(iface: Class!): T ``` Returns an object that implements the given interface to allow access to non-standard methods, or standard methods not exposed by the proxy. If the receiver implements the interface then the result is the receiver or a proxy for the receiver. If the receiver is a wrapper and the wrapped object implements the interface then the result is the wrapped object or a proxy for the wrapped object. Otherwise return the the result of calling`unwrap`recursively on the wrapped object or a proxy for that result. If the receiver is not a wrapper and does not implement the interface, then an`SQLException`is thrown. | Parameters || |---------|---------------------------------------------------------------------------------------------------------------------------------------------------| | `iface` | [Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)\!:A Class defining an interface that the result must implement. | | Return || |---|---------------------------------------------------------------------------------------------| | T | an object that implements the interface. May be a proxy for the actual implementing object. | | Exceptions || |-------------------------|--------------------------------------------------| | `java.sql.SQLException` | If no object found that implements the interface |