Class DataInput
- All Implemented Interfaces:
Cloneable
- Direct Known Subclasses:
ByteArrayDataInput
,FST.BytesReader
,IndexInput
,InputStreamDataInput
,PagedBytes.PagedBytesDataInput
DataInput
may only be used from one thread, because it is not
thread safe (it keeps internal state like file position). To allow
multithreaded use, every DataInput
instance must be cloned before
used in another thread. Subclasses must therefore implement clone()
,
returning a new DataInput
which operates on the same underlying
resource, but positioned independently.
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionclone()
Returns a clone of this stream.abstract byte
readByte()
Reads and returns a single byte.abstract void
readBytes
(byte[] b, int offset, int len) Reads a specified number of bytes into an array at the specified offset.void
readBytes
(byte[] b, int offset, int len, boolean useBuffer) Reads a specified number of bytes into an array at the specified offset with control over whether the read should be buffered (callers who have their own buffer should pass in "false" for useBuffer).int
readInt()
Reads four bytes and returns an int.long
readLong()
Reads eight bytes and returns a long.short
Reads two bytes and returns a short.Reads a string.Reads a Set<String> previously written withDataOutput.writeStringSet(Set)
.Reads a Map<String,String> previously written withDataOutput.writeStringStringMap(Map)
.int
readVInt()
Reads an int stored in variable-length format.long
Reads a long stored in variable-length format.
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Constructor Details
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DataInput
public DataInput()
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Method Details
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readByte
Reads and returns a single byte.- Throws:
IOException
- See Also:
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readBytes
Reads a specified number of bytes into an array at the specified offset.- Parameters:
b
- the array to read bytes intooffset
- the offset in the array to start storing byteslen
- the number of bytes to read- Throws:
IOException
- See Also:
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readBytes
Reads a specified number of bytes into an array at the specified offset with control over whether the read should be buffered (callers who have their own buffer should pass in "false" for useBuffer). Currently onlyBufferedIndexInput
respects this parameter.- Parameters:
b
- the array to read bytes intooffset
- the offset in the array to start storing byteslen
- the number of bytes to readuseBuffer
- set to false if the caller will handle buffering.- Throws:
IOException
- See Also:
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readShort
Reads two bytes and returns a short.- Throws:
IOException
- See Also:
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readInt
Reads four bytes and returns an int.- Throws:
IOException
- See Also:
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readVInt
Reads an int stored in variable-length format. Reads between one and five bytes. Smaller values take fewer bytes. Negative numbers are not supported.The format is described further in
DataOutput.writeVInt(int)
.- Throws:
IOException
- See Also:
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readLong
Reads eight bytes and returns a long.- Throws:
IOException
- See Also:
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readVLong
Reads a long stored in variable-length format. Reads between one and nine bytes. Smaller values take fewer bytes. Negative numbers are not supported.The format is described further in
DataOutput.writeVInt(int)
.- Throws:
IOException
- See Also:
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readString
Reads a string.- Throws:
IOException
- See Also:
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clone
Returns a clone of this stream.Clones of a stream access the same data, and are positioned at the same point as the stream they were cloned from.
Expert: Subclasses must ensure that clones may be positioned at different points in the input from each other and from the stream they were cloned from.
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readStringStringMap
Reads a Map<String,String> previously written withDataOutput.writeStringStringMap(Map)
.- Throws:
IOException
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readStringSet
Reads a Set<String> previously written withDataOutput.writeStringSet(Set)
.- Throws:
IOException
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