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java.lang.Object org.apache.accumulo.core.file.rfile.bcfile.TFile.Reader.Scanner
public static class TFile.Reader.Scanner
The TFile Scanner. The Scanner has an implicit cursor, which, upon creation, points to the first key-value pair in the scan range. If the scan range is empty, the cursor will point to the end of the scan range.
Use atEnd()
to test whether the cursor is at the end location of the scanner.
Use advance()
to move the cursor to the next key-value pair (or end if none exists). Use seekTo methods ( seekTo(byte[])
or seekTo(byte[], int, int)
) to seek to any arbitrary location in the covered range (including backward seeking). Use
rewind()
to seek back to the beginning of the scanner. Use seekToEnd()
to seek to the end of the scanner.
Actual keys and values may be obtained through TFile.Reader.Scanner.Entry
object, which is obtained through entry()
.
Nested Class Summary | |
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class |
TFile.Reader.Scanner.Entry
Entry to a <Key, Value> pair. |
Constructor Summary | |
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protected |
TFile.Reader.Scanner(TFile.Reader reader,
long offBegin,
long offEnd)
Constructor |
protected |
TFile.Reader.Scanner(TFile.Reader reader,
RawComparable beginKey,
RawComparable endKey)
Constructor |
Method Summary | |
---|---|
boolean |
advance()
Move the cursor to the next key-value pair. |
boolean |
atEnd()
Is cursor at the end location? |
void |
close()
Close the scanner. |
TFile.Reader.Scanner.Entry |
entry()
Get an entry to access the key and value. |
void |
lowerBound(byte[] key)
Move the cursor to the first entry whose key is greater than or equal to the input key. |
void |
lowerBound(byte[] key,
int keyOffset,
int keyLen)
Move the cursor to the first entry whose key is greater than or equal to the input key. |
void |
rewind()
Rewind to the first entry in the scanner. |
boolean |
seekTo(byte[] key)
Move the cursor to the first entry whose key is greater than or equal to the input key. |
boolean |
seekTo(byte[] key,
int keyOffset,
int keyLen)
Move the cursor to the first entry whose key is greater than or equal to the input key. |
void |
seekToEnd()
Seek to the end of the scanner. |
void |
upperBound(byte[] key)
Move the cursor to the first entry whose key is strictly greater than the input key. |
void |
upperBound(byte[] key,
int keyOffset,
int keyLen)
Move the cursor to the first entry whose key is strictly greater than the input key. |
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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protected TFile.Reader.Scanner(TFile.Reader reader, long offBegin, long offEnd) throws java.io.IOException
reader
- The TFile reader object.offBegin
- Begin byte-offset of the scan.offEnd
- End byte-offset of the scan.
java.io.IOException
- The offsets will be rounded to the beginning of a compressed block whose offset is greater than or equal to the specified offset.protected TFile.Reader.Scanner(TFile.Reader reader, RawComparable beginKey, RawComparable endKey) throws java.io.IOException
reader
- The TFile reader object.beginKey
- Begin key of the scan. If null, scan from the first endKey
- End key of the scan. If null, scan up to the last java.io.IOException
Method Detail |
---|
public boolean seekTo(byte[] key) throws java.io.IOException
key
- The input key
java.io.IOException
public boolean seekTo(byte[] key, int keyOffset, int keyLen) throws java.io.IOException
key
- The input keykeyOffset
- offset in the key buffer.keyLen
- key buffer length.
java.io.IOException
public void rewind() throws java.io.IOException
java.io.IOException
public void seekToEnd() throws java.io.IOException
java.io.IOException
public void lowerBound(byte[] key) throws java.io.IOException
key
- The input key
java.io.IOException
public void lowerBound(byte[] key, int keyOffset, int keyLen) throws java.io.IOException
key
- The input keykeyOffset
- offset in the key buffer.keyLen
- key buffer length.
java.io.IOException
public void upperBound(byte[] key) throws java.io.IOException
key
- The input key
java.io.IOException
public void upperBound(byte[] key, int keyOffset, int keyLen) throws java.io.IOException
key
- The input keykeyOffset
- offset in the key buffer.keyLen
- key buffer length.
java.io.IOException
public boolean advance() throws java.io.IOException
java.io.IOException
public void close() throws java.io.IOException
close
in interface java.io.Closeable
java.io.IOException
public boolean atEnd()
public TFile.Reader.Scanner.Entry entry() throws java.io.IOException
java.io.IOException
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