com.google.common.io
Class ByteSource

java.lang.Object
  extended by com.google.common.io.ByteSource

public abstract class ByteSource
extends java.lang.Object

A readable source of bytes, such as a file. Unlike an InputStream, a ByteSource is not an open, stateful stream for input that can be read and closed. Instead, it is an immutable supplier of InputStream instances.

ByteSource provides two kinds of methods:

Since:
14.0

Constructor Summary
ByteSource()
           
 
Method Summary
 CharSource asCharSource(java.nio.charset.Charset charset)
          Returns a CharSource view of this byte source that decodes bytes read from this source as characters using the given Charset.
 boolean contentEquals(ByteSource other)
          Checks that the contents of this byte source are equal to the contents of the given byte source.
 long copyTo(ByteSink sink)
          Copies the contents of this byte source to the given ByteSink.
 long copyTo(java.io.OutputStream output)
          Copies the contents of this byte source to the given OutputStream.
 HashCode hash(HashFunction hashFunction)
          Hashes the contents of this byte source using the given hash function.
 java.io.BufferedInputStream openBufferedStream()
          Opens a new BufferedInputStream for reading from this source.
abstract  java.io.InputStream openStream()
          Opens a new InputStream for reading from this source.
 byte[] read()
          Reads the full contents of this byte source as a byte array.
 long size()
          Returns the size of this source in bytes.
 ByteSource slice(long offset, long length)
          Returns a view of a slice of this byte source that is at most length bytes long starting at the given offset.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ByteSource

public ByteSource()
Method Detail

asCharSource

public CharSource asCharSource(java.nio.charset.Charset charset)
Returns a CharSource view of this byte source that decodes bytes read from this source as characters using the given Charset.


openStream

public abstract java.io.InputStream openStream()
                                        throws java.io.IOException
Opens a new InputStream for reading from this source. This method should return a new, independent stream each time it is called.

The caller is responsible for ensuring that the returned stream is closed.

Throws:
java.io.IOException - if an I/O error occurs in the process of opening the stream

openBufferedStream

public java.io.BufferedInputStream openBufferedStream()
                                               throws java.io.IOException
Opens a new BufferedInputStream for reading from this source. This method should return a new, independent stream each time it is called.

The caller is responsible for ensuring that the returned stream is closed.

Throws:
java.io.IOException - if an I/O error occurs in the process of opening the stream

slice

public ByteSource slice(long offset,
                        long length)
Returns a view of a slice of this byte source that is at most length bytes long starting at the given offset.

Throws:
java.lang.IllegalArgumentException - if offset or length is negative

size

public long size()
          throws java.io.IOException
Returns the size of this source in bytes. For most implementations, this is a heavyweight operation that will open a stream, read (or skip, if possible) to the end of the stream and return the total number of bytes that were read.

For some sources, such as a file, this method may use a more efficient implementation. Note that in such cases, it is possible that this method will return a different number of bytes than would be returned by reading all of the bytes (for example, some special files may return a size of 0 despite actually having content when read).

In either case, if this is a mutable source such as a file, the size it returns may not be the same number of bytes a subsequent read would return.

Throws:
java.io.IOException - if an I/O error occurs in the process of reading the size of this source

copyTo

public long copyTo(java.io.OutputStream output)
            throws java.io.IOException
Copies the contents of this byte source to the given OutputStream. Does not close output.

Throws:
java.io.IOException - if an I/O error occurs in the process of reading from this source or writing to output

copyTo

public long copyTo(ByteSink sink)
            throws java.io.IOException
Copies the contents of this byte source to the given ByteSink.

Throws:
java.io.IOException - if an I/O error occurs in the process of reading from this source or writing to sink

read

public byte[] read()
            throws java.io.IOException
Reads the full contents of this byte source as a byte array.

Throws:
java.io.IOException - if an I/O error occurs in the process of reading from this source

hash

public HashCode hash(HashFunction hashFunction)
              throws java.io.IOException
Hashes the contents of this byte source using the given hash function.

Throws:
java.io.IOException - if an I/O error occurs in the process of reading from this source

contentEquals

public boolean contentEquals(ByteSource other)
                      throws java.io.IOException
Checks that the contents of this byte source are equal to the contents of the given byte source.

Throws:
java.io.IOException - if an I/O error occurs in the process of reading from this source or other