Package org.apache.derby.iapi.util
Class UTF8Util
- java.lang.Object
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- org.apache.derby.iapi.util.UTF8Util
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public final class UTF8Util extends java.lang.Object
Utility methods for handling UTF-8 encoded byte streams.Note that when the
skip
methods mention detection of invalid UTF-8 encodings, it only checks the first byte of a character. For multibyte encodings, the second and third byte are not checked for correctness, just skipped and ignored.- See Also:
DataInput
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Nested Class Summary
Nested Classes Modifier and Type Class Description private static class
UTF8Util.SkipCount
Helper class to hold skip counts; one for chars and one for bytes.
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Constructor Summary
Constructors Modifier Constructor Description private
UTF8Util()
This class cannot be instantiated.
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description private static UTF8Util.SkipCount
internalSkip(java.io.InputStream in, long charsToSkip)
Skip characters in the stream.static long
skipFully(java.io.InputStream in, long charsToSkip)
Skip the requested number of characters from the stream.static long
skipUntilEOF(java.io.InputStream in)
Skip until the end-of-stream is reached.
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Method Detail
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skipUntilEOF
public static final long skipUntilEOF(java.io.InputStream in) throws java.io.IOException
Skip until the end-of-stream is reached.- Parameters:
in
- byte stream with UTF-8 encoded characters- Returns:
- The number of characters skipped.
- Throws:
java.io.IOException
- if reading from the stream failsjava.io.UTFDataFormatException
- if an invalid UTF-8 encoding is detected
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skipFully
public static final long skipFully(java.io.InputStream in, long charsToSkip) throws java.io.EOFException, java.io.IOException
Skip the requested number of characters from the stream.- Parameters:
in
- byte stream with UTF-8 encoded characterscharsToSkip
- number of characters to skip- Returns:
- The number of bytes skipped.
- Throws:
java.io.EOFException
- if end-of-stream is reached before the requested number of characters are skippedjava.io.IOException
- if reading from the stream failsjava.io.UTFDataFormatException
- if an invalid UTF-8 encoding is detected
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internalSkip
private static final UTF8Util.SkipCount internalSkip(java.io.InputStream in, long charsToSkip) throws java.io.IOException
Skip characters in the stream.Note that a smaller number than requested might be skipped if the end-of-stream is reached before the specified number of characters has been decoded. It is up to the caller to decide if this is an error or not. For instance, when determining the character length of a stream,
Long.MAX_VALUE
could be passed as the requested number of characters to skip.- Parameters:
in
- byte stream with UTF-8 encoded characterscharsToSkip
- the number of characters to skip- Returns:
- A long array with counts; the characters skipped at position
CHAR_COUNT
, the bytes skipped at positionBYTE_COUNT
. Note that the number of characters skipped may be smaller than the requested number. - Throws:
java.io.IOException
- if reading from the stream failsjava.io.UTFDataFormatException
- if an invalid UTF-8 encoding is detected
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