java.lang.Object
- dev.morphia.aggregation.expressions.StringExpressions

```
public final class StringExpressions
extends Object
```
Defines helper methods for the string expressions

Since:

2.0

Method Summary

All Methods Static Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`static Expression`	`concat(Expression first, Expression... additional)`	Concatenates any number of strings.
`static IndexExpression`	`indexOfBytes(Expression string, Expression substring)`	Searches a string for an occurence of a substring and returns the UTF-8 byte index of the first occurence.
`static IndexExpression`	`indexOfCP(Expression string, Expression substring)`	Searches a string for an occurence of a substring and returns the UTF-8 code point index of the first occurence.
`static TrimExpression`	`ltrim(Expression input)`	Removes whitespace or the specified characters from the beginning of a string.
`static RegexExpression`	`regexFind(Expression input)`	Applies a regular expression (regex) to a string and returns information on the first matched substring.
`static RegexExpression`	`regexFindAll(Expression input)`	Applies a regular expression (regex) to a string and returns information on the all matched substrings.
`static RegexExpression`	`regexMatch(Expression input)`	Applies a regular expression (regex) to a string and returns a boolean that indicates if a match is found or not.
`static Expression`	`replaceAll(Expression input, Expression find, Expression replacement)`	Replaces all instances of a search string in an input string with a replacement string.
`static Expression`	`replaceOne(Expression input, Expression find, Expression replacement)`	Replaces the first instance of a search string in an input string with a replacement string.
`static TrimExpression`	`rtrim(Expression input)`	Removes whitespace or the specified characters from the end of a string.
`static Expression`	`split(Expression input, Expression delimiter)`	Splits a string into substrings based on a delimiter.
`static Expression`	`strcasecmp(Expression first, Expression second)`	Performs case-insensitive string comparison and returns: 0 if two strings are equivalent, 1 if the first string is greater than the second, and -1 if the first string is less than the second.
`static Expression`	`strLenBytes(Expression input)`	Returns the number of UTF-8 encoded bytes in a string.
`static Expression`	`strLenCP(Expression input)`	Returns the number of UTF-8 code points in a string.
`static Expression`	`substr(Expression input, int start, int length)`	Deprecated. Deprecated since version 3.4: $substr is now an alias for `substrBytes(Expression, int, int)`
`static Expression`	`substrBytes(Expression input, int start, int length)`	Returns the substring of a string.
`static Expression`	`substrCP(Expression input, int start, int length)`	Returns the substring of a string.
`static Expression`	`toLower(Expression input)`	Converts a string to lowercase.
`static Expression`	`toString(Expression input)`	Converts value to a string.
`static Expression`	`toUpper(Expression input)`	Converts a string to uppercase.
`static TrimExpression`	`trim(Expression input)`	Removes whitespace or the specified characters from the beginning and end of a string.

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

- Method Detail
  - concat
```
public static Expression concat(Expression first,
                                Expression... additional)
```
    Concatenates any number of strings.
    
    Parameters:
    
    first - the first array expression
    
    additional - additional expressions
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $concat
  - indexOfBytes
```
public static IndexExpression indexOfBytes(Expression string,
                                           Expression substring)
```
    Searches a string for an occurence of a substring and returns the UTF-8 byte index of the first occurence. If the substring is not found, returns -1.
    
    Parameters:
    
    string - the string to search
    
    substring - the target string
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $indexOfBytes
  - indexOfCP
```
public static IndexExpression indexOfCP(Expression string,
                                        Expression substring)
```
    Searches a string for an occurence of a substring and returns the UTF-8 code point index of the first occurence. If the substring is not found, returns -1
    
    Parameters:
    
    string - the string to search
    
    substring - the target string
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $indexOfCP
  - ltrim
```
public static TrimExpression ltrim(Expression input)
```
    Removes whitespace or the specified characters from the beginning of a string.
    
    Parameters:
    
    input - The string to trim. The argument can be any valid expression that resolves to a string.
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $ltrim
  - regexFind
```
public static RegexExpression regexFind(Expression input)
```
    Applies a regular expression (regex) to a string and returns information on the first matched substring.
    
    Parameters:
    
    input - the string to evaluate
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $regexFind
  - regexFindAll
```
public static RegexExpression regexFindAll(Expression input)
```
    Applies a regular expression (regex) to a string and returns information on the all matched substrings.
    
    Parameters:
    
    input - the string to evaluate
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $regexFindAll
  - regexMatch
```
public static RegexExpression regexMatch(Expression input)
```
    Applies a regular expression (regex) to a string and returns a boolean that indicates if a match is found or not.
    
    Parameters:
    
    input - the string to process
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $regexMatch
  - replaceAll
```
public static Expression replaceAll(Expression input,
                                    Expression find,
                                    Expression replacement)
```
    Replaces all instances of a search string in an input string with a replacement string.
    
    Parameters:
    
    input - the input value/source
    
    find - the search expression
    
    replacement - the replacement value
    
    Returns:
    
    the new expression
    
    Since:
    
    2.1
    
    MongoDB documentation
    Aggregration Expression: $replaceAll
  - replaceOne
```
public static Expression replaceOne(Expression input,
                                    Expression find,
                                    Expression replacement)
```
    Replaces the first instance of a search string in an input string with a replacement string.
    
    Parameters:
    
    input - the input value/source
    
    find - the search expression
    
    replacement - the replacement value
    
    Returns:
    
    the new expression
    
    Since:
    
    2.1
    
    MongoDB documentation
    Aggregration Expression: $replaceOne
  - rtrim
```
public static TrimExpression rtrim(Expression input)
```
    Removes whitespace or the specified characters from the end of a string.
    
    Parameters:
    
    input - The string to trim. The argument can be any valid expression that resolves to a string.
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $rtrim
  - split
```
public static Expression split(Expression input,
                               Expression delimiter)
```
    Splits a string into substrings based on a delimiter. Returns an array of substrings. If the delimiter is not found within the string, returns an array containing the original string.
    
    Parameters:
    
    input - The string to split. The argument can be any valid expression that resolves to a string.
    
    delimiter - The delimiter to use when splitting the string expression. delimiter can be any valid expression as long as it resolves to a string.
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $split
  - strLenBytes
```
public static Expression strLenBytes(Expression input)
```
    Returns the number of UTF-8 encoded bytes in a string.
    
    Parameters:
    
    input - the string to process
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $strLenBytes
  - strLenCP
```
public static Expression strLenCP(Expression input)
```
    Returns the number of UTF-8 code points in a string.
    
    Parameters:
    
    input - the string to process
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $strLenCP
  - strcasecmp
```
public static Expression strcasecmp(Expression first,
                                    Expression second)
```
    Performs case-insensitive string comparison and returns: 0 if two strings are equivalent, 1 if the first string is greater than the second, and -1 if the first string is less than the second.
    
    Parameters:
    
    first - the first string to compare
    
    second - the first string to second
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $strcasecmp
  - substr
```
@Deprecated
public static Expression substr(Expression input,
                                int start,
                                int length)
```
    Deprecated.
    Deprecated since version 3.4: $substr is now an alias for substrBytes(Expression, int, int)
    
    Deprecated. Use $substrBytes or $substrCP.
    *note*: Included for completeness and discoverability.
    
    Parameters:
    
    input - the string to process
    
    start - the starting position
    
    length - the number of characters
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $substr
  - substrBytes
```
public static Expression substrBytes(Expression input,
                                     int start,
                                     int length)
```
    Returns the substring of a string. Starts with the character at the specified UTF-8 byte index (zero-based) in the string and continues for the specified number of bytes.
    
    Parameters:
    
    input - the string to process
    
    start - Indicates the starting point of the substring
    
    length - the byte count to include. Can not result in an ending index that is in the middle of a UTF-8 character.
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $substrBytes
  - substrCP
```
public static Expression substrCP(Expression input,
                                  int start,
                                  int length)
```
    Returns the substring of a string. Starts with the character at the specified UTF-8 code point (CP) index (zero-based) in the string and continues for the number of code points specified.
    
    Parameters:
    
    input - the string to process
    
    start - Indicates the starting point of the substring
    
    length - the code points to include.
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $substrCP
  - toLower
```
public static Expression toLower(Expression input)
```
    Converts a string to lowercase. Accepts a single argument expression.
    
    Parameters:
    
    input - the string to process
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $toLower
  - toString
```
public static Expression toString(Expression input)
```
    Converts value to a string.
    
    Parameters:
    
    input - the value to process
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $toString
  - toUpper
```
public static Expression toUpper(Expression input)
```
    Converts a string to uppercase. Accepts a single argument expression.
    
    Parameters:
    
    input - the string to process
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $toUpper
  - trim
```
public static TrimExpression trim(Expression input)
```
    Removes whitespace or the specified characters from the beginning and end of a string.
    
    Parameters:
    
    input - the string to process
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $trim

Class StringExpressions

Method Summary

Methods inherited from class java.lang.Object

Method Detail

concat

indexOfBytes

indexOfCP

ltrim

regexFind

regexFindAll

regexMatch

replaceAll

replaceOne

rtrim

split

strLenBytes

strLenCP

strcasecmp

substr

substrBytes

substrCP

toLower

toString

toUpper

trim