org.apache.lucene.util

Class BytesRef

java.lang.Object

org.apache.lucene.util.BytesRef

All Implemented Interfaces:

Cloneable, Comparable<BytesRef>

public final class BytesRef
extends Object
implements Comparable<BytesRef>, Cloneable

Represents byte[], as a slice (offset + length) into an existing byte[]. The bytes member should never be null; use EMPTY_BYTES if necessary.

Important note: Unless otherwise noted, Lucene uses this class to represent terms that are encoded as UTF8 bytes in the index. To convert them to a Java String (which is UTF16), use utf8ToString(). Using code like new String(bytes, offset, length) to do this is wrong, as it does not respect the correct character set and may return wrong results (depending on the platform's defaults)!

Field Summary

Fields

Modifier and Type	Field and Description
byte[]	bytes The contents of the BytesRef.
static byte[]	EMPTY_BYTES An empty byte array for convenience
int	length Length of used bytes.
int	offset Offset of first valid byte.

Constructor Summary

Constructors

Constructor and Description
BytesRef() Create a BytesRef with EMPTY_BYTES
BytesRef(byte[] bytes) This instance will directly reference bytes w/o making a copy.
BytesRef(byte[] bytes, int offset, int length) This instance will directly reference bytes w/o making a copy.
BytesRef(CharSequence text) Initialize the byte[] from the UTF8 bytes for the provided String.
BytesRef(int capacity) Create a BytesRef pointing to a new array of size capacity.

Method Summary

Methods

Modifier and Type	Method and Description
void	append(BytesRef other) Appends the bytes from the given BytesRef
boolean	bytesEquals(BytesRef other) Expert: compares the bytes against another BytesRef, returning true if the bytes are equal.
BytesRef	clone()
int	compareTo(BytesRef other) Unsigned byte order comparison
void	copyBytes(BytesRef other) Copies the bytes from the given BytesRef
void	copyChars(CharSequence text) Copies the UTF8 bytes for this string.
static BytesRef	deepCopyOf(BytesRef other) Creates a new BytesRef that points to a copy of the bytes from other
boolean	equals(Object other)
static Comparator<BytesRef>	getUTF8SortedAsUnicodeComparator()
static Comparator<BytesRef>	getUTF8SortedAsUTF16Comparator() Deprecated. This comparator is only a transition mechanism
void	grow(int newLength) Used to grow the reference array.
int	hashCode() Calculates the hash code as required by TermsHash during indexing.
String	toString() Returns hex encoded bytes, eg [0x6c 0x75 0x63 0x65 0x6e 0x65]
String	utf8ToString() Interprets stored bytes as UTF8 bytes, returning the resulting string

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

EMPTY_BYTES

public static final byte[] EMPTY_BYTES

An empty byte array for convenience

bytes

public byte[] bytes

The contents of the BytesRef. Should never be null.

offset

public int offset

Offset of first valid byte.

length

public int length

Length of used bytes.

Constructor Detail

BytesRef

public BytesRef()

Create a BytesRef with EMPTY_BYTES

BytesRef

public BytesRef(byte[] bytes,
        int offset,
        int length)

This instance will directly reference bytes w/o making a copy. bytes should not be null.

BytesRef

public BytesRef(byte[] bytes)

This instance will directly reference bytes w/o making a copy. bytes should not be null

BytesRef

public BytesRef(int capacity)

Create a BytesRef pointing to a new array of size capacity. Offset and length will both be zero.

BytesRef

public BytesRef(CharSequence text)

Initialize the byte[] from the UTF8 bytes for the provided String.

Parameters:

text - This must be well-formed unicode text, with no unpaired surrogates.

Method Detail

copyChars

public void copyChars(CharSequence text)

Copies the UTF8 bytes for this string.

Parameters:

text - Must be well-formed unicode text, with no unpaired surrogates or invalid UTF16 code units.

bytesEquals

public boolean bytesEquals(BytesRef other)

Expert: compares the bytes against another BytesRef, returning true if the bytes are equal.

Parameters:

other - Another BytesRef, should not be null.

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

clone

public BytesRef clone()

Overrides:

clone in class Object

hashCode

public int hashCode()

Calculates the hash code as required by TermsHash during indexing.

It is defined as:

  int hash = 0;
  for (int i = offset; i < offset + length; i++) {
    hash = 31*hash + bytes[i];
  }
 

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Overrides:

equals in class Object

utf8ToString

public String utf8ToString()

Interprets stored bytes as UTF8 bytes, returning the resulting string

toString

public String toString()

Returns hex encoded bytes, eg [0x6c 0x75 0x63 0x65 0x6e 0x65]

Overrides:

toString in class Object

copyBytes

public void copyBytes(BytesRef other)

Copies the bytes from the given BytesRef

NOTE: if this would exceed the array size, this method creates a new reference array.

append

public void append(BytesRef other)

Appends the bytes from the given BytesRef

NOTE: if this would exceed the array size, this method creates a new reference array.

grow

public void grow(int newLength)

Used to grow the reference array. In general this should not be used as it does not take the offset into account.

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

compareTo

public int compareTo(BytesRef other)

Unsigned byte order comparison

Specified by:

compareTo in interface Comparable<BytesRef>

getUTF8SortedAsUnicodeComparator

public static Comparator<BytesRef> getUTF8SortedAsUnicodeComparator()

getUTF8SortedAsUTF16Comparator

@Deprecated
public static Comparator<BytesRef> getUTF8SortedAsUTF16Comparator()

Deprecated. This comparator is only a transition mechanism

deepCopyOf

public static BytesRef deepCopyOf(BytesRef other)

Creates a new BytesRef that points to a copy of the bytes from other

The returned BytesRef will have a length of other.length and an offset of zero.