Class StringUtils

java.lang.Object
org.h2.util.StringUtils
public class StringUtils extends Object
A few String utility functions.

  • Field Details

    • softCache

      private static SoftReference<String[]> softCache

    • softCacheCreatedNs

      private static long softCacheCreatedNs

    • HEX

      private static final char[] HEX

    • HEX_DECODE

      private static final int[] HEX_DECODE

    • TO_UPPER_CACHE_LENGTH

      private static final int TO_UPPER_CACHE_LENGTH
      See Also:

    • TO_UPPER_CACHE_MAX_ENTRY_LENGTH

      private static final int TO_UPPER_CACHE_MAX_ENTRY_LENGTH
      See Also:

    • TO_UPPER_CACHE

      private static final String[][] TO_UPPER_CACHE

  • Constructor Details

    • StringUtils

      private StringUtils()

  • Method Details

    • getCache

      private static String[] getCache()

    • toUpperEnglish

      public static String toUpperEnglish(String s)
      Convert a string to uppercase using the English locale.
      Parameters:
      s - the test to convert
      Returns:
      the uppercase text

    • toLowerEnglish

      public static String toLowerEnglish(String s)
      Convert a string to lowercase using the English locale.
      Parameters:
      s - the text to convert
      Returns:
      the lowercase text

    • quoteStringSQL

      public static String quoteStringSQL(String s)
      Convert a string to a SQL literal. Null is converted to NULL. The text is enclosed in single quotes. If there are any special characters, the method STRINGDECODE is used.
      Parameters:
      s - the text to convert.
      Returns:
      the SQL literal

    • quoteStringSQL

      public static StringBuilder quoteStringSQL(StringBuilder builder, String s)
      Convert a string to a SQL character string literal. Null is converted to NULL. If there are any special characters, the Unicode character string literal is used.
      Parameters:
      builder - string builder to append result to
      s - the text to convert
      Returns:
      the specified string builder

    • decodeUnicodeStringSQL

      public static String decodeUnicodeStringSQL(String s, int uencode)
      Decodes a Unicode SQL string.
      Parameters:
      s - the string to decode
      uencode - the code point of UENCODE character, or '\\'
      Returns:
      the decoded string
      Throws:
      DbException - on format exception

    • javaEncode

      public static String javaEncode(String s)
      Convert a string to a Java literal using the correct escape sequences. The literal is not enclosed in double quotes. The result can be used in properties files or in Java source code.
      Parameters:
      s - the text to convert
      Returns:
      the Java representation

    • javaEncode

      public static void javaEncode(String s, StringBuilder buff, boolean forSQL)
      Convert a string to a Java literal using the correct escape sequences. The literal is not enclosed in double quotes. The result can be used in properties files or in Java source code.
      Parameters:
      s - the text to convert
      buff - the Java representation to return
      forSQL - true if we embedding this inside a STRINGDECODE SQL command

    • addAsterisk

      public static String addAsterisk(String s, int index)
      Add an asterisk ('[*]') at the given position. This format is used to show where parsing failed in a statement.
      Parameters:
      s - the text
      index - the position
      Returns:
      the text with asterisk

    • getFormatException

      private static DbException getFormatException(String s, int i)

    • javaDecode

      public static String javaDecode(String s)
      Decode a text that is encoded as a Java string literal. The Java properties file format and Java source code format is supported.
      Parameters:
      s - the encoded string
      Returns:
      the string

    • quoteJavaString

      public static String quoteJavaString(String s)
      Convert a string to the Java literal and enclose it with double quotes. Null will result in "null" (without double quotes).
      Parameters:
      s - the text to convert
      Returns:
      the Java representation

    • quoteJavaStringArray

      public static String quoteJavaStringArray(String[] array)
      Convert a string array to the Java source code that represents this array. Null will be converted to 'null'.
      Parameters:
      array - the string array
      Returns:
      the Java source code (including new String[]{})

    • quoteJavaIntArray

      public static String quoteJavaIntArray(int[] array)
      Convert an int array to the Java source code that represents this array. Null will be converted to 'null'.
      Parameters:
      array - the int array
      Returns:
      the Java source code (including new int[]{})

    • urlEncode

      public static String urlEncode(String s)
      Encode the string as a URL.
      Parameters:
      s - the string to encode
      Returns:
      the encoded string

    • urlDecode

      public static String urlDecode(String encoded)
      Decode the URL to a string.
      Parameters:
      encoded - the encoded URL
      Returns:
      the decoded string

    • arraySplit

      public static String[] arraySplit(String s, char separatorChar, boolean trim)
      Split a string into an array of strings using the given separator. A null string will result in a null array, and an empty string in a zero element array.
      Parameters:
      s - the string to split
      separatorChar - the separator character
      trim - whether each element should be trimmed
      Returns:
      the array list

    • arrayCombine

      public static String arrayCombine(String[] list, char separatorChar)
      Combine an array of strings to one array using the given separator character. A backslash and the separator character and escaped using a backslash.
      Parameters:
      list - the string array
      separatorChar - the separator character
      Returns:
      the combined string

    • xmlAttr

      public static String xmlAttr(String name, String value)
      Creates an XML attribute of the form name="value". A single space is prepended to the name, so that multiple attributes can be concatenated.
      Parameters:
      name - the attribute name
      value - the attribute value
      Returns:
      the attribute

    • xmlNode

      public static String xmlNode(String name, String attributes, String content)
      Create an XML node with optional attributes and content. The data is indented with 4 spaces if it contains a newline character.
      Parameters:
      name - the element name
      attributes - the attributes (may be null)
      content - the content (may be null)
      Returns:
      the node

    • xmlNode

      public static String xmlNode(String name, String attributes, String content, boolean indent)
      Create an XML node with optional attributes and content. The data is indented with 4 spaces if it contains a newline character and the indent parameter is set to true.
      Parameters:
      name - the element name
      attributes - the attributes (may be null)
      content - the content (may be null)
      indent - whether to indent the content if it contains a newline
      Returns:
      the node

    • indent

      public static StringBuilder indent(StringBuilder builder, String s, int spaces, boolean newline)
      Indents a string with spaces and appends it to a specified builder.
      Parameters:
      builder - string builder to append to
      s - the string
      spaces - the number of spaces
      newline - append a newline if there is none
      Returns:
      the specified string builder

    • xmlComment

      public static String xmlComment(String data)
      Escapes a comment. If the data contains '--', it is converted to '- -'. The data is indented with 4 spaces if it contains a newline character.
      Parameters:
      data - the comment text
      Returns:
      <!-- data -->

    • xmlCData

      public static String xmlCData(String data)
      Converts the data to a CDATA element. If the data contains ']]>', it is escaped as a text element.
      Parameters:
      data - the text data
      Returns:
      <![CDATA[data]]>

    • xmlStartDoc

      public static String xmlStartDoc()
      Returns <?xml version="1.0"?>
      Returns:
      <?xml version="1.0"?>

    • xmlText

      public static String xmlText(String text)
      Escapes an XML text element.
      Parameters:
      text - the text data
      Returns:
      the escaped text

    • xmlText

      public static String xmlText(String text, boolean escapeNewline)
      Escapes an XML text element.
      Parameters:
      text - the text data
      escapeNewline - whether to escape newlines
      Returns:
      the escaped text

    • replaceAll

      public static String replaceAll(String s, String before, String after)
      Replace all occurrences of the before string with the after string. Unlike String.replaceAll(String, String) this method reads before and after arguments as plain strings and if before argument is an empty string this method returns original string s.
      Parameters:
      s - the string
      before - the old text
      after - the new text
      Returns:
      the string with the before string replaced

    • quoteIdentifier

      public static String quoteIdentifier(String s)
      Enclose a string with double quotes. A double quote inside the string is escaped using a double quote.
      Parameters:
      s - the text
      Returns:
      the double quoted text

    • quoteIdentifier

      public static StringBuilder quoteIdentifier(StringBuilder builder, String s)
      Enclose a string with double quotes and append it to the specified string builder. A double quote inside the string is escaped using a double quote.
      Parameters:
      builder - string builder to append to
      s - the text
      Returns:
      the specified builder

    • quoteIdentifierOrLiteral

      private static StringBuilder quoteIdentifierOrLiteral(StringBuilder builder, String s, char q)

    • isNullOrEmpty

      public static boolean isNullOrEmpty(String s)
      Check if a String is null or empty (the length is null).
      Parameters:
      s - the string to check
      Returns:
      true if it is null or empty

    • pad

      public static String pad(String string, int n, String padding, boolean right)
      Pad a string. This method is used for the SQL function RPAD and LPAD.
      Parameters:
      string - the original string
      n - the target length
      padding - the padding string
      right - true if the padding should be appended at the end
      Returns:
      the padded string

    • cloneCharArray

      public static char[] cloneCharArray(char[] chars)
      Create a new char array and copy all the data. If the size of the byte array is zero, the same array is returned.
      Parameters:
      chars - the char array (may be null)
      Returns:
      a new char array

    • trim

      public static String trim(String s, boolean leading, boolean trailing, String sp)
      Trim a character from a string.
      Parameters:
      s - the string
      leading - if leading characters should be removed
      trailing - if trailing characters should be removed
      sp - what to remove (only the first character is used) or null for a space
      Returns:
      the trimmed string

    • trimSubstring

      public static String trimSubstring(String s, int beginIndex)
      Trim a whitespace from a substring. Equivalent of substring(beginIndex).trim().
      Parameters:
      s - the string
      beginIndex - start index of substring (inclusive)
      Returns:
      trimmed substring

    • trimSubstring

      public static String trimSubstring(String s, int beginIndex, int endIndex)
      Trim a whitespace from a substring. Equivalent of substring(beginIndex, endIndex).trim().
      Parameters:
      s - the string
      beginIndex - start index of substring (inclusive)
      endIndex - end index of substring (exclusive)
      Returns:
      trimmed substring

    • trimSubstring

      public static StringBuilder trimSubstring(StringBuilder builder, String s, int beginIndex, int endIndex)
      Trim a whitespace from a substring and append it to a specified string builder. Equivalent of builder.append(substring(beginIndex, endIndex).trim()).
      Parameters:
      builder - string builder to append to
      s - the string
      beginIndex - start index of substring (inclusive)
      endIndex - end index of substring (exclusive)
      Returns:
      the specified builder

    • truncateString

      public static String truncateString(String s, int maximumLength)
      Truncates the specified string to the specified length. This method, unlike String.substring(int, int), doesn't break Unicode code points. If the specified length in characters breaks a valid pair of surrogates, the whole pair is not included into result.
      Parameters:
      s - the string to truncate
      maximumLength - the maximum length in characters
      Returns:
      the specified string if it isn't longer than the specified maximum length, and the truncated string otherwise

    • cache

      public static String cache(String s)
      Get the string from the cache if possible. If the string has not been found, it is added to the cache. If there is such a string in the cache, that one is returned.
      Parameters:
      s - the original string
      Returns:
      a string with the same content, if possible from the cache

    • clearCache

      public static void clearCache()
      Clear the cache. This method is used for testing.

    • parseUInt31

      public static int parseUInt31(String s, int start, int end)
      Parses an unsigned 31-bit integer. Neither - nor + signs are allowed.
      Parameters:
      s - string to parse
      start - the beginning index, inclusive
      end - the ending index, exclusive
      Returns:
      the unsigned int not greater than Integer.MAX_VALUE.

    • convertHexToBytes

      public static byte[] convertHexToBytes(String s)
      Convert a hex encoded string to a byte array.
      Parameters:
      s - the hex encoded string
      Returns:
      the byte array

    • convertHexWithSpacesToBytes

      public static ByteArrayOutputStream convertHexWithSpacesToBytes(ByteArrayOutputStream baos, String s, int start, int end)
      Parses a hex encoded string with possible space separators and appends the decoded binary string to the specified output stream.
      Parameters:
      baos - the output stream, or null
      s - the hex encoded string
      start - the start index
      end - the end index, exclusive
      Returns:
      the specified output stream or a new output stream

    • getHexStringException

      private static DbException getHexStringException(int code, String s, int start, int end)

    • convertBytesToHex

      public static String convertBytesToHex(byte[] value)
      Convert a byte array to a hex encoded string.
      Parameters:
      value - the byte array
      Returns:
      the hex encoded string

    • convertBytesToHex

      public static String convertBytesToHex(byte[] value, int len)
      Convert a byte array to a hex encoded string.
      Parameters:
      value - the byte array
      len - the number of bytes to encode
      Returns:
      the hex encoded string

    • convertBytesToHex

      public static StringBuilder convertBytesToHex(StringBuilder builder, byte[] value)
      Convert a byte array to a hex encoded string and appends it to a specified string builder.
      Parameters:
      builder - string builder to append to
      value - the byte array
      Returns:
      the hex encoded string

    • convertBytesToHex

      public static StringBuilder convertBytesToHex(StringBuilder builder, byte[] value, int len)
      Convert a byte array to a hex encoded string and appends it to a specified string builder.
      Parameters:
      builder - string builder to append to
      value - the byte array
      len - the number of bytes to encode
      Returns:
      the hex encoded string

    • appendHex

      public static StringBuilder appendHex(StringBuilder builder, long x, int bytes)
      Appends specified number of trailing bytes from unsigned long value to a specified string builder.
      Parameters:
      builder - string builder to append to
      x - value to append
      bytes - number of bytes to append
      Returns:
      the specified string builder

    • isNumber

      public static boolean isNumber(String s)
      Check if this string is a decimal number.
      Parameters:
      s - the string
      Returns:
      true if it is

    • isWhitespaceOrEmpty

      public static boolean isWhitespaceOrEmpty(String s)
      Check if the specified string is empty or contains only whitespace.
      Parameters:
      s - the string
      Returns:
      whether the specified string is empty or contains only whitespace

    • appendTwoDigits

      public static StringBuilder appendTwoDigits(StringBuilder builder, int positiveValue)
      Append a zero-padded number from 00 to 99 to a string builder.
      Parameters:
      builder - the string builder
      positiveValue - the number to append
      Returns:
      the specified string builder

    • appendZeroPadded

      public static StringBuilder appendZeroPadded(StringBuilder builder, int length, long positiveValue)
      Append a zero-padded number to a string builder.
      Parameters:
      builder - the string builder
      length - the number of characters to append
      positiveValue - the number to append
      Returns:
      the specified string builder

    • escapeMetaDataPattern

      public static String escapeMetaDataPattern(String pattern)
      Escape table or schema patterns used for DatabaseMetaData functions.
      Parameters:
      pattern - the pattern
      Returns:
      the escaped pattern