Package org.apache.lucene.util

Class PagedBytes

java.lang.Object

org.apache.lucene.util.PagedBytes

All Implemented Interfaces:

Accountable

public final class PagedBytes
extends Object
implements Accountable

Represents a logical byte[] as a series of pages. You can write-once into the logical byte[] (append only), using copy, and then retrieve slices (BytesRef) into it using fill.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	PagedBytes.PagedBytesDataInput	Input that transparently iterates over pages
class	PagedBytes.PagedBytesDataOutput	Output that transparently spills to new pages as necessary
static class	PagedBytes.Reader	Provides methods to read BytesRefs from a frozen PagedBytes.

Field Summary

Fields inherited from interface org.apache.lucene.util.Accountable

NULL_ACCOUNTABLE

Constructor Summary

Constructors

Constructor	Description
PagedBytes(int blockBits)	1<<blockBits must be bigger than biggest single BytesRef slice that will be pulled

Method Summary

Modifier and Type	Method	Description
void	copy(IndexInput in, long byteCount)	Read this many bytes from in
void	copy(BytesRef bytes, BytesRef out)	Copy BytesRef in, setting BytesRef out to the result.
long	copyUsingLengthPrefix(BytesRef bytes)	Copy bytes in, writing the length as a 1 or 2 byte vInt prefix.
PagedBytes.Reader	freeze(boolean trim)	Commits final byte[], trimming it if necessary and if trim=true
PagedBytes.PagedBytesDataInput	getDataInput()	Returns a DataInput to read values from this PagedBytes instance.
PagedBytes.PagedBytesDataOutput	getDataOutput()	Returns a DataOutput that you may use to write into this PagedBytes instance.
long	getPointer()
long	ramBytesUsed()	Return the memory usage of this object in bytes.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.lucene.util.Accountable

getChildResources

Constructor Detail

PagedBytes

public PagedBytes(int blockBits)

1<<blockBits must be bigger than biggest single BytesRef slice that will be pulled

Method Detail

copy

public void copy(IndexInput in,
                 long byteCount)
          throws IOException

Read this many bytes from in

Throws:

IOException

copy

public void copy(BytesRef bytes,
                 BytesRef out)

Copy BytesRef in, setting BytesRef out to the result. Do not use this if you will use freeze(true). This only supports bytes.length <= blockSize

freeze

public PagedBytes.Reader freeze(boolean trim)

Commits final byte[], trimming it if necessary and if trim=true

getPointer

public long getPointer()

ramBytesUsed

public long ramBytesUsed()

Description copied from interface: Accountable

Return the memory usage of this object in bytes. Negative values are illegal.

Specified by:

ramBytesUsed in interface Accountable

copyUsingLengthPrefix

public long copyUsingLengthPrefix(BytesRef bytes)

Copy bytes in, writing the length as a 1 or 2 byte vInt prefix.

getDataInput

public PagedBytes.PagedBytesDataInput getDataInput()

Returns a DataInput to read values from this PagedBytes instance.

getDataOutput

public PagedBytes.PagedBytesDataOutput getDataOutput()

Returns a DataOutput that you may use to write into this PagedBytes instance. If you do this, you should not call the other writing methods (eg, copy); results are undefined.