Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Fields](https://developer.android.com/reference/java/io/FilterInputStream#lfields) \| [Protected Ctors](https://developer.android.com/reference/java/io/FilterInputStream#proctors) \| [Methods](https://developer.android.com/reference/java/io/FilterInputStream#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/java/io/FilterInputStream#inhmethods)
# FilterInputStream
` public class FilterInputStream `
` ` ` extends https://developer.android.com/reference/java/io/InputStream ` ` `
|---|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) |||
| ↳ | [java.io.InputStream](https://developer.android.com/reference/java/io/InputStream) ||
| | ↳ | java.io.FilterInputStream |
Known direct subclasses [Base64InputStream](https://developer.android.com/reference/android/util/Base64InputStream), [BufferedInputStream](https://developer.android.com/reference/java/io/BufferedInputStream), [CheckedInputStream](https://developer.android.com/reference/java/util/zip/CheckedInputStream), [CipherInputStream](https://developer.android.com/reference/javax/crypto/CipherInputStream), [DataInputStream](https://developer.android.com/reference/java/io/DataInputStream), [DeflaterInputStream](https://developer.android.com/reference/java/util/zip/DeflaterInputStream), [DigestInputStream](https://developer.android.com/reference/java/security/DigestInputStream), [InflaterInputStream](https://developer.android.com/reference/java/util/zip/InflaterInputStream), [LineNumberInputStream](https://developer.android.com/reference/java/io/LineNumberInputStream), [PushbackInputStream](https://developer.android.com/reference/java/io/PushbackInputStream) [Base64InputStream](https://developer.android.com/reference/android/util/Base64InputStream) An InputStream that does Base64 decoding on the data read through it. [BufferedInputStream](https://developer.android.com/reference/java/io/BufferedInputStream) A `BufferedInputStream` adds functionality to another input stream-namely, the ability to buffer the input and to support the `mark` and `reset` methods. [CheckedInputStream](https://developer.android.com/reference/java/util/zip/CheckedInputStream) An input stream that also maintains a checksum of the data being read. [CipherInputStream](https://developer.android.com/reference/javax/crypto/CipherInputStream) A CipherInputStream is composed of an InputStream and a Cipher so that read() methods return data that are read in from the underlying InputStream but have been additionally processed by the Cipher. [DataInputStream](https://developer.android.com/reference/java/io/DataInputStream) A data input stream lets an application read primitive Java data types from an underlying input stream in a machine-independent way. [DeflaterInputStream](https://developer.android.com/reference/java/util/zip/DeflaterInputStream) Implements an input stream filter for compressing data in the "deflate" compression format. [DigestInputStream](https://developer.android.com/reference/java/security/DigestInputStream) A transparent stream that updates the associated message digest using the bits going through the stream. [InflaterInputStream](https://developer.android.com/reference/java/util/zip/InflaterInputStream) This class implements a stream filter for uncompressing data in the "deflate" compression format. [LineNumberInputStream](https://developer.android.com/reference/java/io/LineNumberInputStream) *This class was deprecated in API level 1. This class incorrectly assumes that bytes adequately represent characters. As of JDK 1.1, the preferred way to operate on character streams is via the new character-stream classes, which include a class for counting line numbers.* [PushbackInputStream](https://developer.android.com/reference/java/io/PushbackInputStream) A `PushbackInputStream` adds functionality to another input stream, namely the ability to "push back" or "unread" bytes, by storing pushed-back bytes in an internal buffer. Known indirect subclasses [GZIPInputStream](https://developer.android.com/reference/java/util/zip/GZIPInputStream), [JarInputStream](https://developer.android.com/reference/java/util/jar/JarInputStream), [ZipInputStream](https://developer.android.com/reference/java/util/zip/ZipInputStream) [GZIPInputStream](https://developer.android.com/reference/java/util/zip/GZIPInputStream) This class implements a stream filter for reading compressed data in the GZIP file format. [JarInputStream](https://developer.android.com/reference/java/util/jar/JarInputStream) The `JarInputStream` class is used to read the contents of a JAR file from any input stream. [ZipInputStream](https://developer.android.com/reference/java/util/zip/ZipInputStream) This class implements an input stream filter for reading files in the ZIP file format.
*** ** * ** ***
A `FilterInputStream` contains some other input stream, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality. The class `FilterInputStream` itself simply overrides all methods of `InputStream` with versions that pass all requests to the contained input stream. Subclasses of `FilterInputStream` may further override some of these methods and may also provide additional methods and fields.
## Summary
| ### Fields ||
|---|---|
| ` protected https://developer.android.com/reference/java/io/InputStream` | `https://developer.android.com/reference/java/io/FilterInputStream#in` The input stream to be filtered. |
| ### Protected constructors ||
|---|---|
| ` https://developer.android.com/reference/java/io/FilterInputStream#FilterInputStream(java.io.InputStream)(https://developer.android.com/reference/java/io/InputStream in) ` Creates a `FilterInputStream` by assigning the argument `in` to the field `this.in` so as to remember it for later use. |
| ### Public methods ||
|---|---|
| ` int` | ` https://developer.android.com/reference/java/io/FilterInputStream#available()() ` Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. |
| ` void` | ` https://developer.android.com/reference/java/io/FilterInputStream#close()() ` Closes this input stream and releases any system resources associated with the stream. |
| ` void` | ` https://developer.android.com/reference/java/io/FilterInputStream#mark(int)(int readlimit) ` Marks the current position in this input stream. |
| ` boolean` | ` https://developer.android.com/reference/java/io/FilterInputStream#markSupported()() ` Tests if this input stream supports the `mark` and `reset` methods. |
| ` int` | ` https://developer.android.com/reference/java/io/FilterInputStream#read()() ` Reads the next byte of data from this input stream. |
| ` int` | ` https://developer.android.com/reference/java/io/FilterInputStream#read(byte[],%20int,%20int)(byte[] b, int off, int len) ` Reads up to `len` bytes of data from this input stream into an array of bytes. |
| ` int` | ` https://developer.android.com/reference/java/io/FilterInputStream#read(byte[])(byte[] b) ` Reads up to `b.length` bytes of data from this input stream into an array of bytes. |
| ` void` | ` https://developer.android.com/reference/java/io/FilterInputStream#reset()() ` Repositions this stream to the position at the time the `mark` method was last called on this input stream. |
| ` long` | ` https://developer.android.com/reference/java/io/FilterInputStream#skip(long)(long n) ` Skips over and discards `n` bytes of data from the input stream. |
### Inherited methods
From class ` https://developer.android.com/reference/java/io/InputStream ` ` int` ` https://developer.android.com/reference/java/io/InputStream#available()() `
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected.
` void` ` https://developer.android.com/reference/java/io/InputStream#close()() `
Closes this input stream and releases any system resources associated with the stream.
` void` ` https://developer.android.com/reference/java/io/InputStream#mark(int)(int readlimit) `
Marks the current position in this input stream.
` boolean` ` https://developer.android.com/reference/java/io/InputStream#markSupported()() `
Tests if this input stream supports the `mark` and `reset` methods.
` static https://developer.android.com/reference/java/io/InputStream` ` https://developer.android.com/reference/java/io/InputStream#nullInputStream()() `
Returns a new `InputStream` that reads no bytes.
` int` ` https://developer.android.com/reference/java/io/InputStream#read(byte[])(byte[] b) `
Reads some number of bytes from the input stream and stores them into the buffer array `b`.
` abstract int` ` https://developer.android.com/reference/java/io/InputStream#read()() `
Reads the next byte of data from the input stream.
` int` ` https://developer.android.com/reference/java/io/InputStream#read(byte[],%20int,%20int)(byte[] b, int off, int len) `
Reads up to `len` bytes of data from the input stream into an array of bytes.
` byte[]` ` https://developer.android.com/reference/java/io/InputStream#readAllBytes()() `
Reads all remaining bytes from the input stream.
` int` ` https://developer.android.com/reference/java/io/InputStream#readNBytes(byte[],%20int,%20int)(byte[] b, int off, int len) `
Reads the requested number of bytes from the input stream into the given byte array.
` byte[]` ` https://developer.android.com/reference/java/io/InputStream#readNBytes(int)(int len) `
Reads up to a specified number of bytes from the input stream.
` void` ` https://developer.android.com/reference/java/io/InputStream#reset()() `
Repositions this stream to the position at the time the `mark` method was last called on this input stream.
` long` ` https://developer.android.com/reference/java/io/InputStream#skip(long)(long n) `
Skips over and discards `n` bytes of data from this input stream.
` void` ` https://developer.android.com/reference/java/io/InputStream#skipNBytes(long)(long n) `
Skips over and discards exactly `n` bytes of data from this input stream.
` long` ` https://developer.android.com/reference/java/io/InputStream#transferTo(java.io.OutputStream)(https://developer.android.com/reference/java/io/OutputStream out) `
Reads all bytes from this input stream and writes the bytes to the given output stream in the order that they are read.
From class ` https://developer.android.com/reference/java/lang/Object ` ` https://developer.android.com/reference/java/lang/Object` ` https://developer.android.com/reference/java/lang/Object#clone()() `
Creates and returns a copy of this object.
` boolean` ` https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object obj) `
Indicates whether some other object is "equal to" this one.
` void` ` https://developer.android.com/reference/java/lang/Object#finalize()() `
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
` final https://developer.android.com/reference/java/lang/Class` ` https://developer.android.com/reference/java/lang/Object#getClass()() `
Returns the runtime class of this `Object`.
` int` ` https://developer.android.com/reference/java/lang/Object#hashCode()() `
Returns a hash code value for the object.
` final void` ` https://developer.android.com/reference/java/lang/Object#notify()() `
Wakes up a single thread that is waiting on this object's monitor.
` final void` ` https://developer.android.com/reference/java/lang/Object#notifyAll()() `
Wakes up all threads that are waiting on this object's monitor.
` https://developer.android.com/reference/java/lang/String` ` https://developer.android.com/reference/java/lang/Object#toString()() `
Returns a string representation of the object.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait(long,%20int)(long timeoutMillis, int nanos) `
Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait(long)(long timeoutMillis) `
Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait()() `
Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*.
From interface ` https://developer.android.com/reference/java/io/Closeable ` ` abstract void` ` https://developer.android.com/reference/java/io/Closeable#close()() `
Closes this stream and releases any system resources associated with it.
From interface ` https://developer.android.com/reference/java/lang/AutoCloseable ` ` abstract void` ` https://developer.android.com/reference/java/lang/AutoCloseable#close()() `
Closes this resource, relinquishing any underlying resources.
## Fields
### in
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
protected InputStream in
```
The input stream to be filtered.
## Protected constructors
### FilterInputStream
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
protected FilterInputStream (InputStream in)
```
Creates a `FilterInputStream` by assigning the argument `in` to the field `this.in` so as to remember it for later use.
| Parameters ||
|---|---|
| `in` | `InputStream`: the underlying input stream, or `null` if this instance is to be created without an underlying stream.
|
## Public methods
### available
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public int available ()
```
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. The next caller might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.
This method returns the result of `https://developer.android.com/reference/java/io/FilterInputStream#in`.available().
| Returns ||
|---|---|
| `int` | an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs. |
### close
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public void close ()
```
Closes this input stream and releases any system resources associated with the stream. This method simply performs `in.close()`.
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs. |
**See also:**
- `https://developer.android.com/reference/java/io/FilterInputStream#in`
### mark
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public void mark (int readlimit)
```
Marks the current position in this input stream. A subsequent call to the `reset` method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.
The `readlimit` argument tells this input stream to allow that many bytes to be read before the mark position gets invalidated.
This method simply performs `in.mark(readlimit)`.
| Parameters ||
|---|---|
| `readlimit` | `int`: the maximum limit of bytes that can be read before the mark position becomes invalid.
|
**See also:**
- `https://developer.android.com/reference/java/io/FilterInputStream#in`
- `https://developer.android.com/reference/java/io/FilterInputStream#reset()`
### markSupported
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public boolean markSupported ()
```
Tests if this input stream supports the `mark` and `reset` methods. This method simply performs `in.markSupported()`.
| Returns ||
|---|---|
| `boolean` | `true` if this stream type supports the `mark` and `reset` method; `false` otherwise.
|
**See also:**
- `https://developer.android.com/reference/java/io/FilterInputStream#in`
- `https://developer.android.com/reference/java/io/InputStream#mark(int)`
- `https://developer.android.com/reference/java/io/InputStream#reset()`
### read
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public int read ()
```
Reads the next byte of data from this input stream. The value byte is returned as an `int` in the range `0` to `255`. If no byte is available because the end of the stream has been reached, the value `-1` is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.
This method simply performs `in.read()` and returns the result.
| Returns ||
|---|---|
| `int` | the next byte of data, or `-1` if the end of the stream is reached.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs. |
**See also:**
- `https://developer.android.com/reference/java/io/FilterInputStream#in`
### read
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public int read (byte[] b,
int off,
int len)
```
Reads up to `len` bytes of data from this input stream into an array of bytes. If `len` is not zero, the method blocks until some input is available; otherwise, no bytes are read and `0` is returned.
This method simply performs `in.read(b, off, len)` and returns the result.
| Parameters ||
|---|---|
| `b` | `byte`: the buffer into which the data is read.
|
| `off` | `int`: the start offset in the destination array `b`
|
| `len` | `int`: the maximum number of bytes read.
|
| Returns ||
|---|---|
| `int` | the total number of bytes read into the buffer, or `-1` if there is no more data because the end of the stream has been reached.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs. |
| `https://developer.android.com/reference/java/lang/IndexOutOfBoundsException` | If `off` is negative, `len` is negative, or `len` is greater than `b.length - off` |
| `https://developer.android.com/reference/java/lang/NullPointerException` | If `b` is `null`. |
**See also:**
- `https://developer.android.com/reference/java/io/FilterInputStream#in`
### read
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public int read (byte[] b)
```
Reads up to `b.length` bytes of data from this input stream into an array of bytes. This method blocks until some input is available.
This method simply performs the call `read(b, 0, b.length)` and returns the result. It is important that it does *not* do `in.read(b)` instead; certain subclasses of `FilterInputStream` depend on the implementation strategy actually used.
| Parameters ||
|---|---|
| `b` | `byte`: the buffer into which the data is read.
|
| Returns ||
|---|---|
| `int` | the total number of bytes read into the buffer, or `-1` if there is no more data because the end of the stream has been reached.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs. |
**See also:**
- `https://developer.android.com/reference/java/io/FilterInputStream#read(byte[],%20int,%20int)`
### reset
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public void reset ()
```
Repositions this stream to the position at the time the `mark` method was last called on this input stream.
This method simply performs `in.reset()`.
Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser.
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if the stream has not been marked or if the mark has been invalidated. |
**See also:**
- `https://developer.android.com/reference/java/io/FilterInputStream#in`
- `https://developer.android.com/reference/java/io/FilterInputStream#mark(int)`
### skip
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public long skip (long n)
```
Skips over and discards `n` bytes of data from the input stream. The `skip` method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly `0`. The actual number of bytes skipped is returned.
This method simply performs `in.skip(n)`.
| Parameters ||
|---|---|
| `n` | `long`: the number of bytes to be skipped.
|
| Returns ||
|---|---|
| `long` | the actual number of bytes skipped.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if `in.skip(n)` throws an IOException. |