# FilterOutputStream Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) # FilterOutputStream ``` open class FilterOutputStream : OutputStream ``` |---|---|----------------------------------------------------------------------------------------------------------| | [kotlin.Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html) ||| | ↳ | [java.io.OutputStream](https://developer.android.com/reference/kotlin/java/io/OutputStream) || | | ↳ | [java.io.FilterOutputStream](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#) | 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| Known Direct Subclasses [Base64OutputStream](https://developer.android.com/reference/kotlin/android/util/Base64OutputStream.html#),[BufferedOutputStream](https://developer.android.com/reference/kotlin/java/io/BufferedOutputStream),[CheckedOutputStream](https://developer.android.com/reference/kotlin/java/util/zip/CheckedOutputStream.html#),[CipherOutputStream](https://developer.android.com/reference/kotlin/javax/crypto/CipherOutputStream.html#),[DataOutputStream](https://developer.android.com/reference/kotlin/java/io/DataOutputStream),[DeflaterOutputStream](https://developer.android.com/reference/kotlin/java/util/zip/DeflaterOutputStream.html#),[DigestOutputStream](https://developer.android.com/reference/kotlin/java/security/DigestOutputStream.html#),[InflaterOutputStream](https://developer.android.com/reference/kotlin/java/util/zip/InflaterOutputStream.html#),[PrintStream](https://developer.android.com/reference/kotlin/java/io/PrintStream) |-----------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [Base64OutputStream](https://developer.android.com/reference/kotlin/android/util/Base64OutputStream.html#) | An OutputStream that does Base64 encoding on the data written to it, writing the resulting data to another OutputStream. | | [BufferedOutputStream](https://developer.android.com/reference/kotlin/java/io/BufferedOutputStream) | The class implements a buffered output stream. | | [CheckedOutputStream](https://developer.android.com/reference/kotlin/java/util/zip/CheckedOutputStream.html#) | An output stream that also maintains a checksum of the data being written. | | [CipherOutputStream](https://developer.android.com/reference/kotlin/javax/crypto/CipherOutputStream.html#) | A CipherOutputStream is composed of an OutputStream and a Cipher so that write() methods first process the data before writing them out to the underlying OutputStream. | | [DataOutputStream](https://developer.android.com/reference/kotlin/java/io/DataOutputStream) | A data output stream lets an application write primitive Java data types to an output stream in a portable way. | | [DeflaterOutputStream](https://developer.android.com/reference/kotlin/java/util/zip/DeflaterOutputStream.html#) | This class implements an output stream filter for compressing data in the "deflate" compression format. | | [DigestOutputStream](https://developer.android.com/reference/kotlin/java/security/DigestOutputStream.html#) | A transparent stream that updates the associated message digest using the bits going through the stream. | | [InflaterOutputStream](https://developer.android.com/reference/kotlin/java/util/zip/InflaterOutputStream.html#) | Implements an output stream filter for uncompressing data stored in the "deflate" compression format. | | [PrintStream](https://developer.android.com/reference/kotlin/java/io/PrintStream) | A`PrintStream`adds functionality to another output stream, namely the ability to print representations of various data values conveniently. | | 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| Known Indirect Subclasses [GZIPOutputStream](https://developer.android.com/reference/kotlin/java/util/zip/GZIPOutputStream.html#),[JarOutputStream](https://developer.android.com/reference/kotlin/java/util/jar/JarOutputStream.html#),[ZipOutputStream](https://developer.android.com/reference/kotlin/java/util/zip/ZipOutputStream.html#) |---------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------| | [GZIPOutputStream](https://developer.android.com/reference/kotlin/java/util/zip/GZIPOutputStream.html#) | This class implements a stream filter for writing compressed data in the GZIP file format. | | [JarOutputStream](https://developer.android.com/reference/kotlin/java/util/jar/JarOutputStream.html#) | The`JarOutputStream`class is used to write the contents of a JAR file to any output stream. | | [ZipOutputStream](https://developer.android.com/reference/kotlin/java/util/zip/ZipOutputStream.html#) | This class implements an output stream filter for writing files in the ZIP file format. | | This class is the superclass of all classes that filter output streams. These streams sit on top of an already existing output stream (the*underlying*output stream) which it uses as its basic sink of data, but possibly transforming the data along the way or providing additional functionality. The class`FilterOutputStream`itself simply overrides all methods of`OutputStream`with versions that pass all requests to the underlying output stream. Subclasses of`FilterOutputStream`may further override some of these methods as well as provide additional methods and fields. ## Summary | Public constructors || |-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---| | [FilterOutputStream](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#FilterOutputStream(java.io.OutputStream))`(`out:` `[OutputStream](https://developer.android.com/reference/kotlin/java/io/OutputStream)!`)` Creates an output stream filter built on top of the specified underlying output stream. | | Public methods || |----------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | open[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [close](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#close())`()` Closes this output stream and releases any system resources associated with the stream. | | open[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [flush](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#flush())`()` Flushes this output stream and forces any buffered output bytes to be written out to the stream. | | open[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [write](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#write(kotlin.ByteArray))`(`b:` `[ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!`)` Writes`b.length`bytes to this output stream. | | open[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [write](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#write(kotlin.ByteArray,%20kotlin.Int,%20kotlin.Int))`(`b:` `[ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!`, `off:` `[Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html)`, `len:` `[Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html)`)` Writes`len`bytes from the specified`byte`array starting at offset`off`to this output stream. | | open[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [write](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#write(kotlin.Int))`(`b:` `[Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html)`)` Writes the specified`byte`to this output stream. | | Inherited functions || |---|---| | From class[OutputStream](https://developer.android.com/reference/kotlin/java/io/OutputStream) |--------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [OutputStream](https://developer.android.com/reference/kotlin/java/io/OutputStream)! | [nullOutputStream](https://developer.android.com/reference/kotlin/java/io/OutputStream#nullOutputStream())`()`
Returns a new`OutputStream`which discards all bytes. The returned stream is initially open. The stream is closed by calling the`close()`method. Subsequent calls to`close()`have no effect. While the stream is open, the`write(int)`,`write(byte[])`, and`write(byte[], int, int)`methods do nothing. After the stream has been closed, these methods all throw`IOException`. The`flush()`method does nothing.
| || | Properties || |--------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------| | [OutputStream](https://developer.android.com/reference/kotlin/java/io/OutputStream)! | [out](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#out:java.io.OutputStream) The underlying output stream to be filtered. | ## Public constructors ### FilterOutputStream Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` FilterOutputStream(out: OutputStream!) ``` Creates an output stream filter built on top of the specified underlying output stream. | Parameters || |-------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `out` | [OutputStream](https://developer.android.com/reference/kotlin/java/io/OutputStream)!:the underlying output stream to be assigned to the field`this.out`for later use, or`null`if this instance is to be created without an underlying stream. | ## Public methods ### close Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun close(): Unit ``` Closes this output stream and releases any system resources associated with the stream. When not already closed, the`close`method of`FilterOutputStream`calls its`flush`method, and then calls the`close`method of its underlying output stream. | Exceptions || |-----------------------|-----------------------------------| | `java.lang.Exception` | if this resource cannot be closed | | `java.io.IOException` | if an I/O error occurs. | | `java.io.IOException` | if an I/O error occurs. | **See Also** - [java.io.FilterOutputStream#out](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#out:java.io.OutputStream) ### flush Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun flush(): Unit ``` Flushes this output stream and forces any buffered output bytes to be written out to the stream. The`flush`method of`FilterOutputStream`calls the`flush`method of its underlying output stream. | Exceptions || |-----------------------|-------------------------| | `java.io.IOException` | if an I/O error occurs. | | `java.io.IOException` | if an I/O error occurs. | **See Also** - [java.io.FilterOutputStream#out](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#out:java.io.OutputStream) ### write Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun write(b: ByteArray!): Unit ``` Writes`b.length`bytes to this output stream. The`write`method of`FilterOutputStream`calls its`write`method of three arguments with the arguments`b`,`0`, and`b.length`. Note that this method does not call the one-argument`write`method of its underlying output stream with the single argument`b`. | Parameters || |-----|------------------------------------------------------------------------------------------------------------------| | `b` | [ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!:the data to be written. | | Exceptions || |-----------------------|-------------------------| | `java.io.IOException` | if an I/O error occurs. | | `java.io.IOException` | if an I/O error occurs. | **See Also** - [java.io.FilterOutputStream#write(byte[], int, int)](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#write(kotlin.ByteArray,%20kotlin.Int,%20kotlin.Int)) ### write Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun write(     b: ByteArray!,     off: Int,     len: Int ): Unit ``` Writes`len`bytes from the specified`byte`array starting at offset`off`to this output stream. The`write`method of`FilterOutputStream`calls the`write`method of one argument on each`byte`to output. Note that this method does not call the`write`method of its underlying output stream with the same arguments. Subclasses of`FilterOutputStream`should provide a more efficient implementation of this method. | Parameters || |-------|----------------------------------------------------------------------------------------------------------| | `b` | [ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!:the data. | | `off` | [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html):the start offset in the data. | | `len` | [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html):the number of bytes to write. | | Exceptions || |-----------------------|-------------------------------------------------------------------------------------------------| | `java.io.IOException` | if an I/O error occurs. In particular, an`IOException`is thrown if the output stream is closed. | | `java.io.IOException` | if an I/O error occurs. | **See Also** - [java.io.FilterOutputStream#write(int)](https://developer.android.com/reference/kotlin/java/io/FilterOutputStream#write(kotlin.Int)) ### write Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun write(b: Int): Unit ``` Writes the specified`byte`to this output stream. The`write`method of`FilterOutputStream`calls the`write`method of its underlying output stream, that is, it performs`out.write(b)`. Implements the abstract`write`method of`OutputStream`. | Parameters || |-----|---------------------------------------------------------------------------------------| | `b` | [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html):the`byte`. | | Exceptions || |-----------------------|-----------------------------------------------------------------------------------------------------------| | `java.io.IOException` | if an I/O error occurs. In particular, an`IOException`may be thrown if the output stream has been closed. | | `java.io.IOException` | if an I/O error occurs. | ## Properties ### out Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` protected var out: OutputStream! ``` The underlying output stream to be filtered.