Class InputStreamUtil
- java.lang.Object
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- org.apache.derby.iapi.services.io.InputStreamUtil
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public final class InputStreamUtil extends java.lang.Object
Utility methods for InputStream that are stand-ins for a small subset of DataInput methods. This avoids pushing a DataInputStream just to get this functionality.
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Field Summary
Fields Modifier and Type Field Description private static int
SKIP_FRAGMENT_SIZE
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Constructor Summary
Constructors Constructor Description InputStreamUtil()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static void
readFully(java.io.InputStream in, byte[] b, int offset, int len)
Read a number of bytes into an array.static int
readLoop(java.io.InputStream in, byte[] b, int offset, int len)
Read a number of bytes into an array.static int
readUnsignedByte(java.io.InputStream in)
Read an unsigned byte from an InputStream, throwing an EOFException if the end of the input is reached.static void
skipFully(java.io.InputStream is, long skippedBytes)
Skips requested number of bytes, throws EOFException if there is too few bytes in the stream.static long
skipPersistent(java.io.InputStream in, long bytesToSkip)
Tries harder to skip the requested number of bytes.static long
skipUntilEOF(java.io.InputStream is)
Skips until EOF, returns number of bytes skipped.
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Field Detail
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SKIP_FRAGMENT_SIZE
private static final int SKIP_FRAGMENT_SIZE
- See Also:
- Constant Field Values
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Method Detail
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readUnsignedByte
public static int readUnsignedByte(java.io.InputStream in) throws java.io.IOException
Read an unsigned byte from an InputStream, throwing an EOFException if the end of the input is reached.- Throws:
java.io.IOException
- if an I/O error occurs.java.io.EOFException
- if the end of the stream is reached- See Also:
DataInput.readUnsignedByte()
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readFully
public static void readFully(java.io.InputStream in, byte[] b, int offset, int len) throws java.io.IOException
Read a number of bytes into an array.- Throws:
java.io.IOException
- if an I/O error occurs.java.io.EOFException
- if the end of the stream is reached- See Also:
DataInput.readFully(byte[])
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readLoop
public static int readLoop(java.io.InputStream in, byte[] b, int offset, int len) throws java.io.IOException
Read a number of bytes into an array. Keep reading in a loop until len bytes are read or EOF is reached or an exception is thrown. Return the number of bytes read. (InputStream.read(byte[],int,int) does not guarantee to read len bytes even if it can do so without reaching EOF or raising an exception.)- Throws:
java.io.IOException
- if an I/O error occurs.
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skipUntilEOF
public static long skipUntilEOF(java.io.InputStream is) throws java.io.IOException
Skips until EOF, returns number of bytes skipped.- Parameters:
is
- InputStream to be skipped.- Returns:
- number of bytes skipped in fact.
- Throws:
java.io.IOException
- if IOException occurs. It doesn't contain EOFException.java.lang.NullPointerException
- if the param 'is' equals null.
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skipFully
public static void skipFully(java.io.InputStream is, long skippedBytes) throws java.io.IOException
Skips requested number of bytes, throws EOFException if there is too few bytes in the stream.- Parameters:
is
- InputStream to be skipped.skippedBytes
- number of bytes to skip. if skippedBytes ≷= zero, do nothing.- Throws:
java.io.EOFException
- if EOF meets before requested number of bytes are skipped.java.io.IOException
- if IOException occurs. It doesn't contain EOFException.java.lang.NullPointerException
- if the param 'is' equals null.
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skipPersistent
public static final long skipPersistent(java.io.InputStream in, long bytesToSkip) throws java.io.IOException
Tries harder to skip the requested number of bytes.Note that even if the method fails to skip the requested number of bytes, it will not throw an exception. If this happens, the caller can be sure that end-of-stream has been reached.
- Parameters:
in
- byte streambytesToSkip
- the number of bytes to skip- Returns:
- The number of bytes skipped.
- Throws:
java.io.IOException
- if reading from the stream fails
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