Package org.apache.lucene.util
Class StringHelper
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- org.apache.lucene.util.StringHelper
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public abstract class StringHelper extends Object
Methods for manipulating strings.- NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.
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Field Summary
Fields Modifier and Type Field Description static intGOOD_FAST_HASH_SEEDPass this as the seed tomurmurhash3_x86_32(byte[], int, int, int).static intID_LENGTHlength in bytes of an ID
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static intbytesDifference(BytesRef priorTerm, BytesRef currentTerm)Compares twoBytesRef, element by element, and returns the number of elements common to both arrays (from the start of each).static booleanendsWith(BytesRef ref, BytesRef suffix)Returnstrueiff the ref ends with the given suffix.static StringidToString(byte[] id)Helper method to render an ID as a string, for debuggingstatic BytesRefintsRefToBytesRef(IntsRef ints)static intmurmurhash3_x86_32(byte[] data, int offset, int len, int seed)Returns the MurmurHash3_x86_32 hash.static intmurmurhash3_x86_32(BytesRef bytes, int seed)static byte[]randomId()Generates a non-cryptographic globally unique id.static intsortKeyLength(BytesRef priorTerm, BytesRef currentTerm)Returns the length ofcurrentTermneeded for use as a sort key.static booleanstartsWith(byte[] ref, BytesRef prefix)Returnstrueiff the ref starts with the given prefix.static booleanstartsWith(BytesRef ref, BytesRef prefix)Returnstrueiff the ref starts with the given prefix.
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Field Detail
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GOOD_FAST_HASH_SEED
public static final int GOOD_FAST_HASH_SEED
Pass this as the seed tomurmurhash3_x86_32(byte[], int, int, int).
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ID_LENGTH
public static final int ID_LENGTH
length in bytes of an ID- See Also:
- Constant Field Values
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Method Detail
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bytesDifference
public static int bytesDifference(BytesRef priorTerm, BytesRef currentTerm)
Compares twoBytesRef, element by element, and returns the number of elements common to both arrays (from the start of each). This method assumes currentTerm comes after priorTerm.
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sortKeyLength
public static int sortKeyLength(BytesRef priorTerm, BytesRef currentTerm)
Returns the length ofcurrentTermneeded for use as a sort key. so thatBytesRef.compareTo(BytesRef)still returns the same result. This method assumes currentTerm comes after priorTerm.
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startsWith
public static boolean startsWith(byte[] ref, BytesRef prefix)Returnstrueiff the ref starts with the given prefix. Otherwisefalse.- Parameters:
ref- thebyte[]to testprefix- the expected prefix- Returns:
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trueiff the ref starts with the given prefix. Otherwisefalse.
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startsWith
public static boolean startsWith(BytesRef ref, BytesRef prefix)
Returnstrueiff the ref starts with the given prefix. Otherwisefalse.- Parameters:
ref- theBytesRefto testprefix- the expected prefix- Returns:
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trueiff the ref starts with the given prefix. Otherwisefalse.
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endsWith
public static boolean endsWith(BytesRef ref, BytesRef suffix)
Returnstrueiff the ref ends with the given suffix. Otherwisefalse.- Parameters:
ref- theBytesRefto testsuffix- the expected suffix- Returns:
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trueiff the ref ends with the given suffix. Otherwisefalse.
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murmurhash3_x86_32
public static int murmurhash3_x86_32(byte[] data, int offset, int len, int seed)Returns the MurmurHash3_x86_32 hash. Original source/tests at https://github.com/yonik/java_util/
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murmurhash3_x86_32
public static int murmurhash3_x86_32(BytesRef bytes, int seed)
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randomId
public static byte[] randomId()
Generates a non-cryptographic globally unique id.
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idToString
public static String idToString(byte[] id)
Helper method to render an ID as a string, for debuggingReturns the string
(null)if the id is null. Otherwise, returns a string representation for debugging. Never throws an exception. The returned string may indicate if the id is definitely invalid.
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