net.sourceforge.pmd.util
Class StringUtil

java.lang.Object
  net.sourceforge.pmd.util.StringUtil

public final class StringUtil
extends java.lang.Object

A number of String-specific utility methods for use by PMD or its IDE plugins.

Author:

BrianRemedios

Field Summary

static java.lang.String[]

EMPTY_STRINGS

Method Summary

static void	appendXmlEscaped(java.lang.StringBuilder buf, java.lang.String src) Appends to a StringBuilder the String src where non-ASCII and XML special chars are escaped.
static void	appendXmlEscaped(java.lang.StringBuilder buf, java.lang.String src, boolean supportUTF8)
static boolean	areSemanticEquals(java.lang.String a, java.lang.String b) Returns true if both strings are effectively null or whitespace, returns false otherwise if they have actual text that differs.
static java.lang.String	asString(java.lang.Object[] items, java.lang.String separator) Formats all items onto a string with separators if more than one exists, return an empty string if the items are null or empty.
static void	asStringOn(java.lang.StringBuffer sb, java.util.Iterator<?> iter, java.lang.String separator) Copies the elements returned by the iterator onto the string buffer each delimited by the separator.
static void	asStringOn(java.lang.StringBuilder sb, java.lang.Object[] items, java.lang.String separator) Copies the array items onto the string builder each delimited by the separator.
static java.lang.String	escapeWhitespace(java.lang.Object o) Replace some whitespace characters so they are visually apparent.
static java.lang.String	htmlEncode(java.lang.String string)
static boolean	isAnyOf(java.lang.String text, java.lang.String... tests) Returns whether the non-null text arg matches any of the test values.
static boolean	isEmpty(java.lang.String value) Returns true if the value arg is either null, empty, or full of whitespace characters.
static boolean	isNotEmpty(java.lang.String value)
static boolean	isSame(java.lang.String s1, java.lang.String s2, boolean trim, boolean ignoreCase, boolean standardizeWhitespace) Are the two String values the same.
static int	lengthOfShortestIn(java.lang.String[] strings) Return the length of the shortest string in the array.
static java.lang.String	lpad(java.lang.String s, int length) Left pads a string.
static int	maxCommonLeadingWhitespaceForAll(java.lang.String[] strings) Determine the maximum number of common leading whitespace characters the strings share in the same sequence.
static java.lang.String	replaceString(java.lang.String original, char oldChar, java.lang.String newString)
static java.lang.String	replaceString(java.lang.String original, java.lang.String oldString, java.lang.String newString)
static boolean	startsWithAny(java.lang.String text, java.lang.String... prefixes) Return whether the non-null text arg starts with any of the prefix values.
static java.lang.String[]	substringsOf(java.lang.String source, char delimiter) Parses the input source using the delimiter specified.
static java.lang.String[]	substringsOf(java.lang.String str, java.lang.String separator) Much more efficient than StringTokenizer.
static java.lang.String[]	trimStartOn(java.lang.String[] strings, int trimDepth) Trims off the leading characters off the strings up to the trimDepth specified.
static java.lang.String	withoutPrefixes(java.lang.String text, java.lang.String... prefixes) Checks for the existence of any of the listed prefixes on the non-null text and removes them.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EMPTY_STRINGS

public static final java.lang.String[] EMPTY_STRINGS

Method Detail

startsWithAny

public static boolean startsWithAny(java.lang.String text,
                                    java.lang.String... prefixes)

Return whether the non-null text arg starts with any of the prefix values.

Parameters:

text -

prefixes -

Returns:

boolean

isAnyOf

public static boolean isAnyOf(java.lang.String text,
                              java.lang.String... tests)

Returns whether the non-null text arg matches any of the test values.

Parameters:

text -

tests -

Returns:

boolean

withoutPrefixes

public static java.lang.String withoutPrefixes(java.lang.String text,
                                               java.lang.String... prefixes)

Checks for the existence of any of the listed prefixes on the non-null text and removes them.

Parameters:

text -

prefixes -

Returns:

String

isEmpty

public static boolean isEmpty(java.lang.String value)

Returns true if the value arg is either null, empty, or full of whitespace characters. More efficient that calling (string).trim().length() == 0

Parameters:

value -

Returns:

true if the value is empty, false otherwise.

isNotEmpty

public static boolean isNotEmpty(java.lang.String value)

Parameters:

value - String

Returns:

boolean

areSemanticEquals

public static boolean areSemanticEquals(java.lang.String a,
                                        java.lang.String b)

Returns true if both strings are effectively null or whitespace, returns false otherwise if they have actual text that differs.

Parameters:

a -

b -

Returns:

boolean

replaceString

public static java.lang.String replaceString(java.lang.String original,
                                             char oldChar,
                                             java.lang.String newString)

Parameters:

original - String

oldChar - char

newString - String

Returns:

String

replaceString

public static java.lang.String replaceString(java.lang.String original,
                                             java.lang.String oldString,
                                             java.lang.String newString)

Parameters:

original - String

oldString - String

newString - String

Returns:

String

appendXmlEscaped

public static void appendXmlEscaped(java.lang.StringBuilder buf,
                                    java.lang.String src)

Appends to a StringBuilder the String src where non-ASCII and XML special chars are escaped.

Parameters:

buf - The destination XML stream

src - The String to append to the stream

escapeWhitespace

public static java.lang.String escapeWhitespace(java.lang.Object o)

Replace some whitespace characters so they are visually apparent.

Parameters:

o -

Returns:

String

htmlEncode

public static java.lang.String htmlEncode(java.lang.String string)

Parameters:

string - String

Returns:

String

appendXmlEscaped

public static void appendXmlEscaped(java.lang.StringBuilder buf,
                                    java.lang.String src,
                                    boolean supportUTF8)

Parameters:

buf -

src -

supportUTF8 - override the default setting, whether special characters should be replaced with entities ( false) or should be included as is ( true).

See Also:

TODO - unify the method above with the one below public to support unit testing - make this package private, once the unit test classes are in the same package.

substringsOf

public static java.lang.String[] substringsOf(java.lang.String source,
                                              char delimiter)

Parses the input source using the delimiter specified. This method is much faster than using the StringTokenizer or String.split(char) approach and serves as a replacement for String.split() for JDK1.3 that doesn't have it. FIXME - we're on JDK 1.4 now, can we replace this with String.split?

Parameters:

source - String

delimiter - char

Returns:

String[]

substringsOf

public static java.lang.String[] substringsOf(java.lang.String str,
                                              java.lang.String separator)

Much more efficient than StringTokenizer.

Parameters:

str - String

separator - char

Returns:

String[]

asStringOn

public static void asStringOn(java.lang.StringBuffer sb,
                              java.util.Iterator<?> iter,
                              java.lang.String separator)

Copies the elements returned by the iterator onto the string buffer each delimited by the separator.

Parameters:

sb - StringBuffer

iter - Iterator

separator - String

asStringOn

public static void asStringOn(java.lang.StringBuilder sb,
                              java.lang.Object[] items,
                              java.lang.String separator)

Copies the array items onto the string builder each delimited by the separator. Does nothing if the array is null or empty.

Parameters:

sb - StringBuilder

items - Object[]

separator - String

lengthOfShortestIn

public static int lengthOfShortestIn(java.lang.String[] strings)

Return the length of the shortest string in the array. If the collection is empty or any one of them is null then it returns 0.

Parameters:

strings - String[]

Returns:

int

maxCommonLeadingWhitespaceForAll

public static int maxCommonLeadingWhitespaceForAll(java.lang.String[] strings)

Determine the maximum number of common leading whitespace characters the strings share in the same sequence. Useful for determining how many leading characters can be removed to shift all the text in the strings to the left without misaligning them.

Parameters:

strings - String[]

Returns:

int

trimStartOn

public static java.lang.String[] trimStartOn(java.lang.String[] strings,
                                             int trimDepth)

Trims off the leading characters off the strings up to the trimDepth specified. Returns the same strings if trimDepth = 0

Parameters:

strings -

trimDepth -

Returns:

String[]

lpad

public static java.lang.String lpad(java.lang.String s,
                                    int length)

Left pads a string.

Parameters:

s - The String to pad

length - The desired minimum length of the resulting padded String

Returns:

The resulting left padded String

isSame

public static boolean isSame(java.lang.String s1,
                             java.lang.String s2,
                             boolean trim,
                             boolean ignoreCase,
                             boolean standardizeWhitespace)

Are the two String values the same. The Strings can be optionally trimmed before checking. The Strings can be optionally compared ignoring case. The Strings can be have embedded whitespace standardized before comparing. Two null values are treated as equal.

Parameters:

s1 - The first String.

s2 - The second String.

trim - Indicates if the Strings should be trimmed before comparison.

ignoreCase - Indicates if the case of the Strings should ignored during comparison.

standardizeWhitespace - Indicates if the embedded whitespace should be standardized before comparison.

Returns:

true if the Strings are the same, false otherwise.

asString

public static java.lang.String asString(java.lang.Object[] items,
                                        java.lang.String separator)

Formats all items onto a string with separators if more than one exists, return an empty string if the items are null or empty.

Parameters:

items - Object[]

separator - String

Returns:

String