🌐 Text (Apache Hadoop Main 3.4.2 API)

java.lang.Object
- org.apache.hadoop.io.BinaryComparable
- - org.apache.hadoop.io.Text

All Implemented Interfaces:

Comparable<BinaryComparable>, Writable, WritableComparable<BinaryComparable>
```
@Stringable
 @InterfaceAudience.Public
 @InterfaceStability.Stable
public class Text
extends BinaryComparable
implements WritableComparable<BinaryComparable>
```
This class stores text using standard UTF8 encoding. It provides methods to serialize, deserialize, and compare texts at byte level. The type of length is integer and is serialized using zero-compressed format.
In addition, it provides methods for string traversal without converting the byte array to a string.
Also includes utilities for serializing/deserialing a string, coding/decoding a string, checking if a byte array contains valid UTF8 code, calculating the length of an encoded string.

Field Summary

Fields
Modifier and Type Field and Description

static int DEFAULT_MAX_LEN

Fields
Modifier and Type	Field and Description
`static int`	`DEFAULT_MAX_LEN`

Constructor Summary

Constructors
Constructor and Description
`Text()` Construct an empty text string.
`Text(byte[] utf8)` Construct from a byte array.
`Text(String string)` Construct from a string.
`Text(Text utf8)` Construct from another text.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`append(byte[] utf8, int start, int len)` Append a range of bytes to the end of the given text.
`static int`	`bytesToCodePoint(ByteBuffer bytes)`
`int`	`charAt(int position)` Returns the Unicode Scalar Value (32-bit integer value) for the character at `position`.
`void`	`clear()` Clear the string to empty.
`byte[]`	`copyBytes()`
`static String`	`decode(byte[] utf8)`
`static String`	`decode(byte[] utf8, int start, int length)`
`static String`	`decode(byte[] utf8, int start, int length, boolean replace)`
`static ByteBuffer`	`encode(String string)` Converts the provided String to bytes using the UTF-8 encoding.
`static ByteBuffer`	`encode(String string, boolean replace)` Converts the provided String to bytes using the UTF-8 encoding.
`boolean`	`equals(Object o)` Returns true iff `o` is a Text with the same length and same contents.
`int`	`find(String what)`
`int`	`find(String what, int start)` Finds any occurrence of `what` in the backing buffer, starting as position `start`.
`byte[]`	`getBytes()` Returns the raw bytes; however, only data up to `getLength()` is valid.
`int`	`getLength()` Returns the number of bytes in the byte array.
`int`	`getTextLength()`
`int`	`hashCode()` Return a hash of the bytes returned from {#getBytes()}.
`void`	`readFields(DataInput in)` Deserialize the fields of this object from `in`.
`void`	`readFields(DataInput in, int maxLength)`
`static String`	`readString(DataInput in)`
`static String`	`readString(DataInput in, int maxLength)`
`void`	`readWithKnownLength(DataInput in, int len)` Read a Text object whose length is already known.
`void`	`set(byte[] utf8)` Set to a utf8 byte array.
`void`	`set(byte[] utf8, int start, int len)` Set the Text to range of bytes.
`void`	`set(String string)` Set to contain the contents of a string.
`void`	`set(Text other)` Copy a text.
`static void`	`skip(DataInput in)` Skips over one Text in the input.
`String`	`toString()`
`static int`	`utf8Length(String string)` For the given string, returns the number of UTF-8 bytes required to encode the string.
`static void`	`validateUTF8(byte[] utf8)` Check if a byte array contains valid UTF-8.
`static void`	`validateUTF8(byte[] utf8, int start, int len)` Check to see if a byte array is valid UTF-8.
`void`	`write(DataOutput out)` Serialize.
`void`	`write(DataOutput out, int maxLength)`
`static int`	`writeString(DataOutput out, String s)` Write a UTF8 encoded string to out.
`static int`	`writeString(DataOutput out, String s, int maxLength)`

Methods inherited from class org.apache.hadoop.io.BinaryComparable
compareTo, compareTo

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Comparable
compareTo

- Field Detail
  - DEFAULT_MAX_LEN
```
public static final int DEFAULT_MAX_LEN
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - Text
```
public Text()
```
    Construct an empty text string.
  - Text
```
public Text(String string)
```
    Construct from a string.
    
    Parameters:
    
    string - input string.
  - Text
```
public Text(Text utf8)
```
    Construct from another text.
    
    Parameters:
    
    utf8 - input utf8.
  - Text
```
public Text(byte[] utf8)
```
    Construct from a byte array.
    
    Parameters:
    
    utf8 - input utf8.
- Method Detail
  - copyBytes
```
public byte[] copyBytes()
```
    Returns:
    
    Get a copy of the bytes that is exactly the length of the data. See getBytes() for faster access to the underlying array.
  - getBytes
```
public byte[] getBytes()
```
    Returns the raw bytes; however, only data up to getLength() is valid. Please use copyBytes() if you need the returned array to be precisely the length of the data.
    
    Specified by:
    
    getBytes in class BinaryComparable
    
    Returns:
    
    getBytes.
  - getLength
```
public int getLength()
```
    Returns the number of bytes in the byte array.
    
    Specified by:
    
    getLength in class BinaryComparable
    
    Returns:
    
    length.
  - getTextLength
```
public int getTextLength()
```
    Returns:
    
    Returns the length of this text. The length is equal to the number of Unicode code units in the text.
  - charAt
```
public int charAt(int position)
```
    Returns the Unicode Scalar Value (32-bit integer value) for the character at position. Note that this method avoids using the converter or doing String instantiation.
    
    Parameters:
    
    position - input position.
    
    Returns:
    
    the Unicode scalar value at position or -1 if the position is invalid or points to a trailing byte
  - find
```
public int find(String what)
```
  - find
```
public int find(String what,
                int start)
```
    Finds any occurrence of what in the backing buffer, starting as position start. The starting position is measured in bytes and the return value is in terms of byte position in the buffer. The backing buffer is not converted to a string for this operation.
    
    Parameters:
    
    what - input what.
    
    start - input start.
    
    Returns:
    
    byte position of the first occurrence of the search string in the UTF-8 buffer or -1 if not found
  - set
```
public void set(String string)
```
    Set to contain the contents of a string.
    
    Parameters:
    
    string - input string.
  - set
```
public void set(byte[] utf8)
```
    Set to a utf8 byte array. If the length of utf8 is zero, actually clear bytes and any existing data is lost.
    
    Parameters:
    
    utf8 - input utf8.
  - set
```
public void set(Text other)
```
    Copy a text.
    
    Parameters:
    
    other - other.
  - set
```
public void set(byte[] utf8,
                int start,
                int len)
```
    Set the Text to range of bytes.
    
    Parameters:
    
    utf8 - the data to copy from
    
    start - the first position of the new string
    
    len - the number of bytes of the new string
  - append
```
public void append(byte[] utf8,
                   int start,
                   int len)
```
    Append a range of bytes to the end of the given text.
    
    Parameters:
    
    utf8 - the data to copy from
    
    start - the first position to append from utf8
    
    len - the number of bytes to append
  - clear
```
public void clear()
```
    Clear the string to empty. Note: For performance reasons, this call does not clear the underlying byte array that is retrievable via getBytes(). In order to free the byte-array memory, call set(byte[]) with an empty byte array (For example, new byte[0]).
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - readFields
```
public void readFields(DataInput in)
                throws IOException
```
    Description copied from interface: Writable
    
    Deserialize the fields of this object from in.
    For efficiency, implementations should attempt to re-use storage in the existing object where possible.
    
    Specified by:
    
    readFields in interface Writable
    
    Parameters:
    
    in - DataInput to deseriablize this object from.
    
    Throws:
    
    IOException - any other problem for readFields.
  - readFields
```
public void readFields(DataInput in,
                       int maxLength)
                throws IOException
```
    Throws:
    
    IOException
  - skip
```
public static void skip(DataInput in)
                 throws IOException
```
    Skips over one Text in the input.
    
    Parameters:
    
    in - input in.
    
    Throws:
    
    IOException - raised on errors performing I/O.
  - readWithKnownLength
```
public void readWithKnownLength(DataInput in,
                                int len)
                         throws IOException
```
    Read a Text object whose length is already known. This allows creating Text from a stream which uses a different serialization format.
    
    Parameters:
    
    in - input in.
    
    len - input len.
    
    Throws:
    
    IOException - raised on errors performing I/O.
  - write
```
public void write(DataOutput out)
           throws IOException
```
    Serialize. Write this object to out length uses zero-compressed encoding.
    
    Specified by:
    
    write in interface Writable
    
    Parameters:
    
    out - DataOuput to serialize this object into.
    
    Throws:
    
    IOException - any other problem for write.
    
    See Also:
    
    Writable.write(DataOutput)
  - write
```
public void write(DataOutput out,
                  int maxLength)
           throws IOException
```
    Throws:
    
    IOException
  - equals
```
public boolean equals(Object o)
```
    Returns true iff o is a Text with the same length and same contents.
    
    Overrides:
    
    equals in class BinaryComparable
  - hashCode
```
public int hashCode()
```
    Description copied from class: BinaryComparable
    
    Return a hash of the bytes returned from {#getBytes()}.
    
    Overrides:
    
    hashCode in class BinaryComparable
    
    See Also:
    
    WritableComparator.hashBytes(byte[],int)
  - decode
```
public static String decode(byte[] utf8)
                     throws CharacterCodingException
```
    Parameters:
    
    utf8 - input utf8.
    
    Returns:
    
    Converts the provided byte array to a String using the UTF-8 encoding. If the input is malformed, replace by a default value.
    
    Throws:
    
    CharacterCodingException - when a character encoding or decoding error occurs.
  - decode
```
public static String decode(byte[] utf8,
                            int start,
                            int length)
                     throws CharacterCodingException
```
    Throws:
    
    CharacterCodingException
  - decode
```
public static String decode(byte[] utf8,
                            int start,
                            int length,
                            boolean replace)
                     throws CharacterCodingException
```
    Parameters:
    
    utf8 - input utf8.
    
    start - input start.
    
    length - input length.
    
    replace - input replace.
    
    Returns:
    
    Converts the provided byte array to a String using the UTF-8 encoding. If replace is true, then malformed input is replaced with the substitution character, which is U+FFFD. Otherwise the method throws a MalformedInputException.
    
    Throws:
    
    CharacterCodingException - when a character encoding or decoding error occurs.
  - encode
```
public static ByteBuffer encode(String string)
                         throws CharacterCodingException
```
    Converts the provided String to bytes using the UTF-8 encoding. If the input is malformed, invalid chars are replaced by a default value.
    
    Parameters:
    
    string - input string.
    
    Returns:
    
    ByteBuffer: bytes stores at ByteBuffer.array() and length is ByteBuffer.limit()
    
    Throws:
    
    CharacterCodingException - when a character encoding or decoding error occurs.
  - encode
```
public static ByteBuffer encode(String string,
                                boolean replace)
                         throws CharacterCodingException
```
    Converts the provided String to bytes using the UTF-8 encoding. If replace is true, then malformed input is replaced with the substitution character, which is U+FFFD. Otherwise the method throws a MalformedInputException.
    
    Parameters:
    
    string - input string.
    
    replace - input replace.
    
    Returns:
    
    ByteBuffer: bytes stores at ByteBuffer.array() and length is ByteBuffer.limit()
    
    Throws:
    
    CharacterCodingException - when a character encoding or decoding error occurs.
  - readString
```
public static String readString(DataInput in)
                         throws IOException
```
    Parameters:
    
    in - input in.
    
    Returns:
    
    Read a UTF8 encoded string from in.
    
    Throws:
    
    IOException - raised on errors performing I/O.
  - readString
```
public static String readString(DataInput in,
                                int maxLength)
                         throws IOException
```
    Parameters:
    
    in - input datainput.
    
    maxLength - input maxLength.
    
    Returns:
    
    Read a UTF8 encoded string with a maximum size.
    
    Throws:
    
    IOException - raised on errors performing I/O.
  - writeString
```
public static int writeString(DataOutput out,
                              String s)
                       throws IOException
```
    Write a UTF8 encoded string to out.
    
    Parameters:
    
    out - input out.
    
    s - input s.
    
    Returns:
    
    a UTF8 encoded string to out.
    
    Throws:
    
    IOException - raised on errors performing I/O.
  - writeString
```
public static int writeString(DataOutput out,
                              String s,
                              int maxLength)
                       throws IOException
```
    Parameters:
    
    out - input out.
    
    s - input s.
    
    maxLength - input maxLength.
    
    Returns:
    
    Write a UTF8 encoded string with a maximum size to out.
    
    Throws:
    
    IOException - raised on errors performing I/O.
  - validateUTF8
```
public static void validateUTF8(byte[] utf8)
                         throws MalformedInputException
```
    Check if a byte array contains valid UTF-8.
    
    Parameters:
    
    utf8 - byte array
    
    Throws:
    
    MalformedInputException - if the byte array contains invalid UTF-8
  - validateUTF8
```
public static void validateUTF8(byte[] utf8,
                                int start,
                                int len)
                         throws MalformedInputException
```
    Check to see if a byte array is valid UTF-8.
    
    Parameters:
    
    utf8 - the array of bytes
    
    start - the offset of the first byte in the array
    
    len - the length of the byte sequence
    
    Throws:
    
    MalformedInputException - if the byte array contains invalid bytes
  - bytesToCodePoint
```
public static int bytesToCodePoint(ByteBuffer bytes)
```
    Parameters:
    
    bytes - input bytes.
    
    Returns:
    
    Returns the next code point at the current position in the buffer. The buffer's position will be incremented. Any mark set on this buffer will be changed by this method!
  - utf8Length
```
public static int utf8Length(String string)
```
    For the given string, returns the number of UTF-8 bytes required to encode the string.
    
    Parameters:
    
    string - text to encode
    
    Returns:
    
    number of UTF-8 bytes required to encode

Class Text

Field Summary

Constructor Summary

Method Summary

Methods inherited from class org.apache.hadoop.io.BinaryComparable

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.Comparable

Field Detail

DEFAULT_MAX_LEN

Constructor Detail

Text

Text

Text

Text

Method Detail

copyBytes

getBytes

getLength

getTextLength

charAt

find

find

set

set

set

set

append

clear

toString

readFields

readFields

skip

readWithKnownLength

write

write

equals

hashCode

decode

decode

decode

encode

encode

readString

readString

writeString

writeString

validateUTF8

validateUTF8

bytesToCodePoint

utf8Length