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java.lang.Object org.apache.accumulo.core.file.rfile.bcfile.TFile.Reader
public static class TFile.Reader
TFile Reader. Users may only read TFiles by creating TFile.Reader.Scanner. objects. A scanner may scan the whole TFile (createScanner()
) ,
a portion of TFile based on byte offsets ( createScanner(long, long)
), or a portion of TFile with keys fall in a certain key range (for
sorted TFile only, createScanner(byte[], byte[])
or createScanner(RawComparable, RawComparable)
).
Nested Class Summary | |
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static class |
TFile.Reader.Scanner
The TFile Scanner. |
Constructor Summary | |
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TFile.Reader(org.apache.hadoop.fs.FSDataInputStream fsdis,
long fileLength,
org.apache.hadoop.conf.Configuration conf)
Constructor |
Method Summary | |
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void |
close()
Close the reader. |
TFile.Reader.Scanner |
createScanner()
Get a scanner than can scan the whole TFile. |
TFile.Reader.Scanner |
createScanner(byte[] beginKey,
byte[] endKey)
Get a scanner that covers a portion of TFile based on keys. |
TFile.Reader.Scanner |
createScanner(long offset,
long length)
Get a scanner that covers a portion of TFile based on byte offsets. |
TFile.Reader.Scanner |
createScanner(RawComparable beginKey,
RawComparable endKey)
Get a scanner that covers a specific key range. |
java.util.Comparator<RawComparable> |
getComparator()
Get an instance of the RawComparator that is constructed based on the string comparator representation. |
java.lang.String |
getComparatorName()
Get the string representation of the comparator. |
java.util.Comparator<TFile.Reader.Scanner.Entry> |
getEntryComparator()
Get a Comparator object to compare Entries. |
long |
getEntryCount()
Get the number of key-value pair entries in TFile. |
RawComparable |
getFirstKey()
Get the first key in the TFile. |
RawComparable |
getKeyNear(long offset)
Get a sample key that is within a block whose starting offset is greater than or equal to the specified offset. |
RawComparable |
getLastKey()
Get the last key in the TFile. |
java.io.DataInputStream |
getMetaBlock(java.lang.String name)
Stream access to a meta block.`` |
boolean |
isSorted()
Is the TFile sorted? |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public TFile.Reader(org.apache.hadoop.fs.FSDataInputStream fsdis, long fileLength, org.apache.hadoop.conf.Configuration conf) throws java.io.IOException
fsdis
- FS input stream of the TFile.fileLength
- The length of TFile. This is required because we have no easy way of knowing the actual size of the input file through the File input stream.conf
-
java.io.IOException
Method Detail |
---|
public void close() throws java.io.IOException
close
in interface java.io.Closeable
java.io.IOException
public java.lang.String getComparatorName()
public boolean isSorted()
public long getEntryCount()
public RawComparable getFirstKey() throws java.io.IOException
java.io.IOException
public RawComparable getLastKey() throws java.io.IOException
java.io.IOException
public java.util.Comparator<TFile.Reader.Scanner.Entry> getEntryComparator()
public java.util.Comparator<RawComparable> getComparator()
public java.io.DataInputStream getMetaBlock(java.lang.String name) throws java.io.IOException, MetaBlockDoesNotExist
name
- The name of the meta block.
java.io.IOException
- on I/O error.
MetaBlockDoesNotExist
- If the meta block with the name does not exist.public RawComparable getKeyNear(long offset) throws java.io.IOException
offset
- The file offset.
java.io.IOException
public TFile.Reader.Scanner createScanner() throws java.io.IOException
java.io.IOException
public TFile.Reader.Scanner createScanner(long offset, long length) throws java.io.IOException
offset
- The beginning byte offset in the TFile.length
- The length of the region.
java.io.IOException
public TFile.Reader.Scanner createScanner(byte[] beginKey, byte[] endKey) throws java.io.IOException
beginKey
- Begin key of the scan (inclusive). If null, scan from the first key-value entry of the TFile.endKey
- End key of the scan (exclusive). If null, scan up to the last key-value entry of the TFile.
java.io.IOException
public TFile.Reader.Scanner createScanner(RawComparable beginKey, RawComparable endKey) throws java.io.IOException
beginKey
- Begin key of the scan (inclusive). If null, scan from the first key-value entry of the TFile.endKey
- End key of the scan (exclusive). If null, scan up to the last key-value entry of the TFile.
java.io.IOException
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