FileInputStream (ocap 1.2 API)

java.lang.Object
- java.io.InputStream
- - java.io.FileInputStream

```
public class FileInputStream
extends InputStream
```
A FileInputStream obtains input bytes from a file in a file system. What files are available depends on the host environment.
FileInputStream is meant for reading streams of raw bytes such as image data. For reading streams of characters, consider using FileReader.

Since:

JDK1.0

Version:

1.45, 02/02/00

Author:

Arthur van Hoff

See Also:
File, FileDescriptor, FileOutputStream

Constructor Summary

Constructors
Constructor and Description
`FileInputStream(File file)` Creates a `FileInputStream` by opening a connection to an actual file, the file named by the `File` object `file` in the file system.
`FileInputStream(FileDescriptor fdObj)` Creates a `FileInputStream` by using the file descriptor `fdObj`, which represents an existing connection to an actual file in the file system.
`FileInputStream(String name)` Creates a `FileInputStream` by opening a connection to an actual file, the file named by the path name `name` in the file system.

Method Summary

Methods
Modifier and Type	Method and Description
`int`	`available()` Returns the number of bytes that can be read from this file input stream without blocking.
`void`	`close()` Closes this file input stream and releases any system resources associated with the stream.
`protected void`	`finalize()` Ensures that the `close` method of this file input stream is called when there are no more references to it.
`FileDescriptor`	`getFD()` Returns the `FileDescriptor` object that represents the connection to the actual file in the file system being used by this `FileInputStream`.
`int`	`read()` Reads a byte of data from this input stream.
`int`	`read(byte[] b)` Reads up to `b.length` bytes of data from this input stream into an array of bytes.
`int`	`read(byte[] b, int off, int len)` Reads up to `len` bytes of data from this input stream into an array of bytes.
`long`	`skip(long n)` Skips over and discards `n` bytes of data from the input stream.

Methods inherited from class java.io.InputStream
mark, markSupported, reset

Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - FileInputStream
```
public FileInputStream(String name)
                throws FileNotFoundException
```
    Creates a FileInputStream by opening a connection to an actual file, the file named by the path name name in the file system. A new FileDescriptor object is created to represent this file connection.
    First, if there is a security manager, its checkRead method is called with the name argument as its argument.
    If the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading then a FileNotFoundException is thrown.
    
    Parameters:
    name - the system-dependent file name.
    
    Throws:
    
    FileNotFoundException - if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.
    
    SecurityException - if a security manager exists and its checkRead method denies read access to the file.
    See Also:
    SecurityManager.checkRead(java.lang.String)
  - FileInputStream
```
public FileInputStream(File file)
                throws FileNotFoundException
```
    Creates a FileInputStream by opening a connection to an actual file, the file named by the File object file in the file system. A new FileDescriptor object is created to represent this file connection.
    First, if there is a security manager, its checkRead method is called with the path represented by the file argument as its argument.
    If the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading then a FileNotFoundException is thrown.
    
    Parameters:
    file - the file to be opened for reading.
    
    Throws:
    
    FileNotFoundException - if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.
    
    SecurityException - if a security manager exists and its checkRead method denies read access to the file.
    See Also:
    File.getPath(), SecurityManager.checkRead(java.lang.String)
  - FileInputStream
```
public FileInputStream(FileDescriptor fdObj)
```
    Creates a FileInputStream by using the file descriptor fdObj, which represents an existing connection to an actual file in the file system.
    If there is a security manager, its checkRead method is called with the file descriptor fdObj as its argument to see if it's ok to read the file descriptor. If read access is denied to the file descriptor a SecurityException is thrown.
    If fdObj is null then a NullPointerException is thrown.
    
    Parameters:
    fdObj - the file descriptor to be opened for reading.
    
    Throws:
    
    SecurityException - if a security manager exists and its checkRead method denies read access to the file descriptor.
    See Also:
    SecurityManager.checkRead(java.io.FileDescriptor)
- Method Detail
  - read
```
public int read()
         throws IOException
```
    Reads a byte of data from this input stream. This method blocks if no input is yet available.
    
    Specified by:
    
    read in class InputStream
    
    Returns:
    the next byte of data, or -1 if the end of the file is reached.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - read
```
public int read(byte[] b)
         throws IOException
```
    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.
    
    Overrides:
    
    read in class InputStream
    
    Parameters:
    b - the buffer into which the data is read.
    
    Returns:
    the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.
    
    Throws:
    
    IOException - if an I/O error occurs.
    See Also:
    InputStream.read(byte[], int, int)
  - read
```
public int read(byte[] b,
       int off,
       int len)
         throws IOException
```
    Reads up to len bytes of data from this input stream into an array of bytes. This method blocks until some input is available.
    
    Overrides:
    
    read in class InputStream
    
    Parameters:
    b - the buffer into which the data is read.
    off - the start offset of the data.
    len - the maximum number of bytes read.
    
    Returns:
    the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.
    
    Throws:
    
    IOException - if an I/O error occurs.
    See Also:
    InputStream.read()
  - skip
```
public long skip(long n)
          throws IOException
```
    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.
    
    Overrides:
    
    skip in class InputStream
    
    Parameters:
    n - the number of bytes to be skipped.
    
    Returns:
    the actual number of bytes skipped.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - available
```
public int available()
              throws IOException
```
    Returns the number of bytes that can be read from this file input stream without blocking.
    
    Overrides:
    
    available in class InputStream
    
    Returns:
    the number of bytes that can be read from this file input stream without blocking.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - close
```
public void close()
           throws IOException
```
    Closes this file input stream and releases any system resources associated with the stream.
    If this stream has an associated channel then the channel is closed as well.
    
    Overrides:
    
    close in class InputStream
    
    Throws:
    
    IOException - if an I/O error occurs.
  - getFD
```
public final FileDescriptor getFD()
                           throws IOException
```
    Returns the FileDescriptor object that represents the connection to the actual file in the file system being used by this FileInputStream.
    
    Returns:
    the file descriptor object associated with this stream.
    
    Throws:
    
    IOException - if an I/O error occurs.
    See Also:
    FileDescriptor
  - finalize
```
protected void finalize()
                 throws IOException
```
    Ensures that the close method of this file input stream is called when there are no more references to it.
    
    Overrides:
    
    finalize in class Object
    
    Throws:
    
    IOException - if an I/O error occurs.
    See Also:
    close()

Class FileInputStream

Constructor Summary

Method Summary

Methods inherited from class java.io.InputStream

Methods inherited from class java.lang.Object

Constructor Detail

FileInputStream

FileInputStream

FileInputStream

Method Detail

read

read

read

skip

available

close

getFD

finalize