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)!

BytesRef implements Comparable. The underlying byte arrays are sorted lexicographically, numerically treating elements as unsigned. This is identical to Unicode codepoint order.

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

Modifier and Type	Method and Description
boolean	bytesEquals(BytesRef other) Expert: compares the bytes against another BytesRef, returning true if the bytes are equal.
BytesRef	clone() Returns a shallow clone of this instance (the underlying bytes are not copied and will be shared by both the returned object and this object.
int	compareTo(BytesRef other) Unsigned byte order comparison
static BytesRef	deepCopyOf(BytesRef other) Creates a new BytesRef that points to a copy of the bytes from other
boolean	equals(Object other)
int	hashCode() Calculates the hash code as required by TermsHash during indexing.
boolean	isValid() Performs internal consistency checks.
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

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()

Returns a shallow clone of this instance (the underlying bytes are not copied and will be shared by both the returned object and this object.

Overrides:

clone in class Object

See Also:

deepCopyOf(org.apache.lucene.util.BytesRef)

hashCode

public int hashCode()

Calculates the hash code as required by TermsHash during indexing.

This is currently implemented as MurmurHash3 (32 bit), using the seed from StringHelper.GOOD_FAST_HASH_SEED, but is subject to change from release to release.

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

compareTo

public int compareTo(BytesRef other)

Unsigned byte order comparison

Specified by:

compareTo in interface Comparable<BytesRef>

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.

isValid

public boolean isValid()

Performs internal consistency checks. Always returns true (or throws IllegalStateException)