Class StrBuilder
- All Implemented Interfaces:
Cloneable
The main differences from StringBuffer/StringBuilder are:
- Not synchronized
- Not final
- Subclasses have direct access to character array
- Additional methods
- appendWithSeparators - adds an array of values, with a separator
- appendPadding - adds a length padding characters
- appendFixedLength - adds a fixed width field to the builder
- toCharArray/getChars - simpler ways to get a range of the character array
- delete - delete char or string
- replace - search and replace for a char or string
- leftString/rightString/midString - substring without exceptions
- contains - whether the builder contains a char or string
- size/clear/isEmpty - collections style API methods
- asTokenizer - uses the internal buffer as the source of a StrTokenizer
- asReader - uses the internal buffer as the source of a Reader
- asWriter - allows a Writer to write directly to the internal buffer
The aim has been to provide an API that mimics very closely what StringBuffer
provides, but with additional methods. It should be noted that some edge cases,
with invalid indices or null input, have been altered - see individual methods.
The biggest of these changes is that by default, null will not output the text
'null'. This can be controlled by a property, setNullText(String)
.
Prior to 3.0, this class implemented Cloneable but did not implement the clone method so could not be used. From 3.0 onwards it no longer implements the interface.
- Since:
- 2.2
- Version:
- $Id: StrBuilder.java 1057349 2011-01-10 20:40:49Z niallp $
-
Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionConstructor that creates an empty builder initial capacity 32 characters.StrBuilder
(int initialCapacity) Constructor that creates an empty builder the specified initial capacity.StrBuilder
(String str) Constructor that creates a builder from the string, allocating 32 extra characters for growth. -
Method Summary
Modifier and TypeMethodDescriptionappend
(boolean value) Appends a boolean value to the string builder.append
(char ch) Appends a char value to the string builder.append
(char[] chars) Appends a char array to the string builder.append
(char[] chars, int startIndex, int length) Appends a char array to the string builder.append
(double value) Appends a double value to the string builder usingString.valueOf
.append
(float value) Appends a float value to the string builder usingString.valueOf
.append
(int value) Appends an int value to the string builder usingString.valueOf
.append
(long value) Appends a long value to the string builder usingString.valueOf
.Appends an object to this string builder.Appends a string to this string builder.append
(StringBuffer str) Appends a string buffer to this string builder.append
(StringBuffer str, int startIndex, int length) Appends part of a string buffer to this string builder.Appends part of a string to this string builder.append
(StrBuilder str) Appends another string builder to this string builder.append
(StrBuilder str, int startIndex, int length) Appends part of a string builder to this string builder.Appends each item in an array to the builder without any separators.appendAll
(Collection coll) Appends each item in a collection to the builder without any separators.Appends each item in an iterator to the builder without any separators.appendFixedWidthPadLeft
(int value, int width, char padChar) Appends an object to the builder padding on the left to a fixed width.appendFixedWidthPadLeft
(Object obj, int width, char padChar) Appends an object to the builder padding on the left to a fixed width.appendFixedWidthPadRight
(int value, int width, char padChar) Appends an object to the builder padding on the right to a fixed length.appendFixedWidthPadRight
(Object obj, int width, char padChar) Appends an object to the builder padding on the right to a fixed length.appendln
(boolean value) Appends a boolean value followed by a new line to the string builder.appendln
(char ch) Appends a char value followed by a new line to the string builder.appendln
(char[] chars) Appends a char array followed by a new line to the string builder.appendln
(char[] chars, int startIndex, int length) Appends a char array followed by a new line to the string builder.appendln
(double value) Appends a double value followed by a new line to the string builder usingString.valueOf
.appendln
(float value) Appends a float value followed by a new line to the string builder usingString.valueOf
.appendln
(int value) Appends an int value followed by a new line to the string builder usingString.valueOf
.appendln
(long value) Appends a long value followed by a new line to the string builder usingString.valueOf
.Appends an object followed by a new line to this string builder.Appends a string followed by a new line to this string builder.appendln
(StringBuffer str) Appends a string buffer followed by a new line to this string builder.appendln
(StringBuffer str, int startIndex, int length) Appends part of a string buffer followed by a new line to this string builder.Appends part of a string followed by a new line to this string builder.appendln
(StrBuilder str) Appends another string builder followed by a new line to this string builder.appendln
(StrBuilder str, int startIndex, int length) Appends part of a string builder followed by a new line to this string builder.Appends the new line string to this string builder.Appends the text representingnull
to this string builder.appendPadding
(int length, char padChar) Appends the pad character to the builder the specified number of times.appendSeparator
(char separator) Appends a separator if the builder is currently non-empty.appendSeparator
(char standard, char defaultIfEmpty) Append one of both separators to the builder If the builder is currently empty it will append the defaultIfEmpty-separator Otherwise it will append the standard-separator The separator is appended usingappend(char)
.appendSeparator
(char separator, int loopIndex) Appends a separator to the builder if the loop index is greater than zero.appendSeparator
(String separator) Appends a separator if the builder is currently non-empty.appendSeparator
(String separator, int loopIndex) Appends a separator to the builder if the loop index is greater than zero.appendSeparator
(String standard, String defaultIfEmpty) Appends one of both separators to the StrBuilder.appendWithSeparators
(Object[] array, String separator) Appends an array placing separators between each value, but not before the first or after the last.appendWithSeparators
(Collection coll, String separator) Appends a collection placing separators between each value, but not before the first or after the last.appendWithSeparators
(Iterator it, String separator) Appends an iterator placing separators between each value, but not before the first or after the last.asReader()
Gets the contents of this builder as a Reader.Creates a tokenizer that can tokenize the contents of this builder.asWriter()
Gets this builder as a Writer that can be written to.int
capacity()
Gets the current size of the internal character array buffer.char
charAt
(int index) Gets the character at the specified index.clear()
Clears the string builder (convenience Collections API style method).clone()
Clone this object.boolean
contains
(char ch) Checks if the string builder contains the specified char.boolean
Checks if the string builder contains the specified string.boolean
contains
(StrMatcher matcher) Checks if the string builder contains a string matched using the specified matcher.delete
(int startIndex, int endIndex) Deletes the characters between the two specified indices.deleteAll
(char ch) Deletes the character wherever it occurs in the builder.Deletes the string wherever it occurs in the builder.deleteAll
(StrMatcher matcher) Deletes all parts of the builder that the matcher matches.deleteCharAt
(int index) Deletes the character at the specified index.deleteFirst
(char ch) Deletes the character wherever it occurs in the builder.deleteFirst
(String str) Deletes the string wherever it occurs in the builder.deleteFirst
(StrMatcher matcher) Deletes the first match within the builder using the specified matcher.boolean
Checks whether this builder ends with the specified string.ensureCapacity
(int capacity) Checks the capacity and ensures that it is at least the size specified.boolean
Checks the contents of this builder against another to see if they contain the same character content.boolean
equals
(StrBuilder other) Checks the contents of this builder against another to see if they contain the same character content.boolean
equalsIgnoreCase
(StrBuilder other) Checks the contents of this builder against another to see if they contain the same character content ignoring case.char[]
getChars
(char[] destination) Copies the character array into the specified array.void
getChars
(int startIndex, int endIndex, char[] destination, int destinationIndex) Copies the character array into the specified array.Gets the text to be appended when a new line is added.Gets the text to be appended when null is added.int
hashCode()
Gets a suitable hash code for this builder.int
indexOf
(char ch) Searches the string builder to find the first reference to the specified char.int
indexOf
(char ch, int startIndex) Searches the string builder to find the first reference to the specified char.int
Searches the string builder to find the first reference to the specified string.int
Searches the string builder to find the first reference to the specified string starting searching from the given index.int
indexOf
(StrMatcher matcher) Searches the string builder using the matcher to find the first match.int
indexOf
(StrMatcher matcher, int startIndex) Searches the string builder using the matcher to find the first match searching from the given index.insert
(int index, boolean value) Inserts the value into this builder.insert
(int index, char value) Inserts the value into this builder.insert
(int index, char[] chars) Inserts the character array into this builder.insert
(int index, char[] chars, int offset, int length) Inserts part of the character array into this builder.insert
(int index, double value) Inserts the value into this builder.insert
(int index, float value) Inserts the value into this builder.insert
(int index, int value) Inserts the value into this builder.insert
(int index, long value) Inserts the value into this builder.Inserts the string representation of an object into this builder.Inserts the string into this builder.boolean
isEmpty()
Checks is the string builder is empty (convenience Collections API style method).int
lastIndexOf
(char ch) Searches the string builder to find the last reference to the specified char.int
lastIndexOf
(char ch, int startIndex) Searches the string builder to find the last reference to the specified char.int
lastIndexOf
(String str) Searches the string builder to find the last reference to the specified string.int
lastIndexOf
(String str, int startIndex) Searches the string builder to find the last reference to the specified string starting searching from the given index.int
lastIndexOf
(StrMatcher matcher) Searches the string builder using the matcher to find the last match.int
lastIndexOf
(StrMatcher matcher, int startIndex) Searches the string builder using the matcher to find the last match searching from the given index.leftString
(int length) Extracts the leftmost characters from the string builder without throwing an exception.int
length()
Gets the length of the string builder.midString
(int index, int length) Extracts some characters from the middle of the string builder without throwing an exception.Minimizes the capacity to the actual length of the string.Replaces a portion of the string builder with another string.replace
(StrMatcher matcher, String replaceStr, int startIndex, int endIndex, int replaceCount) Advanced search and replaces within the builder using a matcher.replaceAll
(char search, char replace) Replaces the search character with the replace character throughout the builder.replaceAll
(String searchStr, String replaceStr) Replaces the search string with the replace string throughout the builder.replaceAll
(StrMatcher matcher, String replaceStr) Replaces all matches within the builder with the replace string.replaceFirst
(char search, char replace) Replaces the first instance of the search character with the replace character in the builder.replaceFirst
(String searchStr, String replaceStr) Replaces the first instance of the search string with the replace string.replaceFirst
(StrMatcher matcher, String replaceStr) Replaces the first match within the builder with the replace string.reverse()
Reverses the string builder placing each character in the opposite index.rightString
(int length) Extracts the rightmost characters from the string builder without throwing an exception.setCharAt
(int index, char ch) Sets the character at the specified index.setLength
(int length) Updates the length of the builder by either dropping the last characters or adding filler of unicode zero.setNewLineText
(String newLine) Sets the text to be appended when a new line is added.setNullText
(String nullText) Sets the text to be appended when null is added.int
size()
Gets the length of the string builder.boolean
startsWith
(String str) Checks whether this builder starts with the specified string.substring
(int start) Extracts a portion of this string builder as a string.substring
(int startIndex, int endIndex) Extracts a portion of this string builder as a string.char[]
Copies the builder's character array into a new character array.char[]
toCharArray
(int startIndex, int endIndex) Copies part of the builder's character array into a new character array.toString()
Gets a String version of the string builder, creating a new instance each time the method is called.Gets a StringBuffer version of the string builder, creating a new instance each time the method is called.trim()
Trims the builder by removing characters less than or equal to a space from the beginning and end.protected void
validateIndex
(int index) Validates parameters defining a single index in the builder.protected int
validateRange
(int startIndex, int endIndex) Validates parameters defining a range of the builder.
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Field Details
-
buffer
protected char[] bufferInternal data storage. -
size
protected int sizeCurrent size of the buffer.
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-
Constructor Details
-
StrBuilder
public StrBuilder()Constructor that creates an empty builder initial capacity 32 characters. -
StrBuilder
public StrBuilder(int initialCapacity) Constructor that creates an empty builder the specified initial capacity.- Parameters:
initialCapacity
- the initial capacity, zero or less will be converted to 32
-
StrBuilder
Constructor that creates a builder from the string, allocating 32 extra characters for growth.- Parameters:
str
- the string to copy, null treated as blank string
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-
Method Details
-
getNewLineText
Gets the text to be appended when a new line is added.- Returns:
- the new line text, null means use system default
-
setNewLineText
Sets the text to be appended when a new line is added.- Parameters:
newLine
- the new line text, null means use system default- Returns:
- this, to enable chaining
-
getNullText
Gets the text to be appended when null is added.- Returns:
- the null text, null means no append
-
setNullText
Sets the text to be appended when null is added.- Parameters:
nullText
- the null text, null means no append- Returns:
- this, to enable chaining
-
length
public int length()Gets the length of the string builder.- Returns:
- the length
-
setLength
Updates the length of the builder by either dropping the last characters or adding filler of unicode zero.- Parameters:
length
- the length to set to, must be zero or positive- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the length is negative
-
capacity
public int capacity()Gets the current size of the internal character array buffer.- Returns:
- the capacity
-
ensureCapacity
Checks the capacity and ensures that it is at least the size specified.- Parameters:
capacity
- the capacity to ensure- Returns:
- this, to enable chaining
-
minimizeCapacity
Minimizes the capacity to the actual length of the string.- Returns:
- this, to enable chaining
-
size
public int size()Gets the length of the string builder.This method is the same as
length()
and is provided to match the API of Collections.- Returns:
- the length
-
isEmpty
public boolean isEmpty()Checks is the string builder is empty (convenience Collections API style method).This method is the same as checking
length()
and is provided to match the API of Collections.- Returns:
true
if the size is0
.
-
clear
Clears the string builder (convenience Collections API style method).This method does not reduce the size of the internal character buffer. To do that, call
clear()
followed byminimizeCapacity()
.This method is the same as
setLength(int)
called with zero and is provided to match the API of Collections.- Returns:
- this, to enable chaining
-
charAt
public char charAt(int index) Gets the character at the specified index.- Parameters:
index
- the index to retrieve, must be valid- Returns:
- the character at the index
- Throws:
IndexOutOfBoundsException
- if the index is invalid- See Also:
-
setCharAt
Sets the character at the specified index.- Parameters:
index
- the index to setch
- the new character- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid- See Also:
-
deleteCharAt
Deletes the character at the specified index.- Parameters:
index
- the index to delete- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid- See Also:
-
toCharArray
public char[] toCharArray()Copies the builder's character array into a new character array.- Returns:
- a new array that represents the contents of the builder
-
toCharArray
public char[] toCharArray(int startIndex, int endIndex) Copies part of the builder's character array into a new character array.- Parameters:
startIndex
- the start index, inclusive, must be validendIndex
- the end index, exclusive, must be valid except that if too large it is treated as end of string- Returns:
- a new array that holds part of the contents of the builder
- Throws:
IndexOutOfBoundsException
- if startIndex is invalid, or if endIndex is invalid (but endIndex greater than size is valid)
-
getChars
public char[] getChars(char[] destination) Copies the character array into the specified array.- Parameters:
destination
- the destination array, null will cause an array to be created- Returns:
- the input array, unless that was null or too small
-
getChars
public void getChars(int startIndex, int endIndex, char[] destination, int destinationIndex) Copies the character array into the specified array.- Parameters:
startIndex
- first index to copy, inclusive, must be validendIndex
- last index, exclusive, must be validdestination
- the destination array, must not be null or too smalldestinationIndex
- the index to start copying in destination- Throws:
NullPointerException
- if the array is nullIndexOutOfBoundsException
- if any index is invalid
-
appendNewLine
Appends the new line string to this string builder.The new line string can be altered using
setNewLineText(String)
. This might be used to force the output to always use Unix line endings even when on Windows.- Returns:
- this, to enable chaining
-
appendNull
Appends the text representingnull
to this string builder.- Returns:
- this, to enable chaining
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append
Appends an object to this string builder. Appending null will callappendNull()
.- Parameters:
obj
- the object to append- Returns:
- this, to enable chaining
-
append
Appends a string to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string to append- Returns:
- this, to enable chaining
-
append
Appends part of a string to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string to appendstartIndex
- the start index, inclusive, must be validlength
- the length to append, must be valid- Returns:
- this, to enable chaining
-
append
Appends a string buffer to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string buffer to append- Returns:
- this, to enable chaining
-
append
Appends part of a string buffer to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string to appendstartIndex
- the start index, inclusive, must be validlength
- the length to append, must be valid- Returns:
- this, to enable chaining
-
append
Appends another string builder to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string builder to append- Returns:
- this, to enable chaining
-
append
Appends part of a string builder to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string to appendstartIndex
- the start index, inclusive, must be validlength
- the length to append, must be valid- Returns:
- this, to enable chaining
-
append
Appends a char array to the string builder. Appending null will callappendNull()
.- Parameters:
chars
- the char array to append- Returns:
- this, to enable chaining
-
append
Appends a char array to the string builder. Appending null will callappendNull()
.- Parameters:
chars
- the char array to appendstartIndex
- the start index, inclusive, must be validlength
- the length to append, must be valid- Returns:
- this, to enable chaining
-
append
Appends a boolean value to the string builder.- Parameters:
value
- the value to append- Returns:
- this, to enable chaining
-
append
Appends a char value to the string builder.- Parameters:
ch
- the value to append- Returns:
- this, to enable chaining
-
append
Appends an int value to the string builder usingString.valueOf
.- Parameters:
value
- the value to append- Returns:
- this, to enable chaining
-
append
Appends a long value to the string builder usingString.valueOf
.- Parameters:
value
- the value to append- Returns:
- this, to enable chaining
-
append
Appends a float value to the string builder usingString.valueOf
.- Parameters:
value
- the value to append- Returns:
- this, to enable chaining
-
append
Appends a double value to the string builder usingString.valueOf
.- Parameters:
value
- the value to append- Returns:
- this, to enable chaining
-
appendln
Appends an object followed by a new line to this string builder. Appending null will callappendNull()
.- Parameters:
obj
- the object to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends a string followed by a new line to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends part of a string followed by a new line to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string to appendstartIndex
- the start index, inclusive, must be validlength
- the length to append, must be valid- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends a string buffer followed by a new line to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string buffer to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends part of a string buffer followed by a new line to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string to appendstartIndex
- the start index, inclusive, must be validlength
- the length to append, must be valid- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends another string builder followed by a new line to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string builder to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends part of a string builder followed by a new line to this string builder. Appending null will callappendNull()
.- Parameters:
str
- the string to appendstartIndex
- the start index, inclusive, must be validlength
- the length to append, must be valid- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends a char array followed by a new line to the string builder. Appending null will callappendNull()
.- Parameters:
chars
- the char array to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends a char array followed by a new line to the string builder. Appending null will callappendNull()
.- Parameters:
chars
- the char array to appendstartIndex
- the start index, inclusive, must be validlength
- the length to append, must be valid- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends a boolean value followed by a new line to the string builder.- Parameters:
value
- the value to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends a char value followed by a new line to the string builder.- Parameters:
ch
- the value to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends an int value followed by a new line to the string builder usingString.valueOf
.- Parameters:
value
- the value to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends a long value followed by a new line to the string builder usingString.valueOf
.- Parameters:
value
- the value to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends a float value followed by a new line to the string builder usingString.valueOf
.- Parameters:
value
- the value to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendln
Appends a double value followed by a new line to the string builder usingString.valueOf
.- Parameters:
value
- the value to append- Returns:
- this, to enable chaining
- Since:
- 2.3
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appendAll
Appends each item in an array to the builder without any separators. Appending a null array will have no effect. Each object is appended usingappend(Object)
.- Parameters:
array
- the array to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendAll
Appends each item in a collection to the builder without any separators. Appending a null collection will have no effect. Each object is appended usingappend(Object)
.- Parameters:
coll
- the collection to append- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendAll
Appends each item in an iterator to the builder without any separators. Appending a null iterator will have no effect. Each object is appended usingappend(Object)
.- Parameters:
it
- the iterator to append- Returns:
- this, to enable chaining
- Since:
- 2.3
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appendWithSeparators
Appends an array placing separators between each value, but not before the first or after the last. Appending a null array will have no effect. Each object is appended usingappend(Object)
.- Parameters:
array
- the array to appendseparator
- the separator to use, null means no separator- Returns:
- this, to enable chaining
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appendWithSeparators
Appends a collection placing separators between each value, but not before the first or after the last. Appending a null collection will have no effect. Each object is appended usingappend(Object)
.- Parameters:
coll
- the collection to appendseparator
- the separator to use, null means no separator- Returns:
- this, to enable chaining
-
appendWithSeparators
Appends an iterator placing separators between each value, but not before the first or after the last. Appending a null iterator will have no effect. Each object is appended usingappend(Object)
.- Parameters:
it
- the iterator to appendseparator
- the separator to use, null means no separator- Returns:
- this, to enable chaining
-
appendSeparator
Appends a separator if the builder is currently non-empty. Appending a null separator will have no effect. The separator is appended usingappend(String)
.This method is useful for adding a separator each time around the loop except the first.
for (Iterator it = list.iterator(); it.hasNext(); ) { appendSeparator(","); append(it.next()); }
Note that for this simple example, you should useappendWithSeparators(Collection, String)
.- Parameters:
separator
- the separator to use, null means no separator- Returns:
- this, to enable chaining
- Since:
- 2.3
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appendSeparator
Appends one of both separators to the StrBuilder. If the builder is currently empty it will append the defaultIfEmpty-separator Otherwise it will append the standard-separator Appending a null separator will have no effect. The separator is appended usingappend(String)
.This method is for example useful for constructing queries
StrBuilder whereClause = new StrBuilder(); if(searchCommand.getPriority() != null) { whereClause.appendSeparator(" and", " where"); whereClause.append(" priority = ?") } if(searchCommand.getComponent() != null) { whereClause.appendSeparator(" and", " where"); whereClause.append(" component = ?") } selectClause.append(whereClause)
- Parameters:
standard
- the separator if builder is not empty, null means no separatordefaultIfEmpty
- the separator if builder is empty, null means no separator- Returns:
- this, to enable chaining
- Since:
- 2.5
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appendSeparator
Appends a separator if the builder is currently non-empty. The separator is appended usingappend(char)
.This method is useful for adding a separator each time around the loop except the first.
for (Iterator it = list.iterator(); it.hasNext(); ) { appendSeparator(','); append(it.next()); }
Note that for this simple example, you should useappendWithSeparators(Collection, String)
.- Parameters:
separator
- the separator to use- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendSeparator
Append one of both separators to the builder If the builder is currently empty it will append the defaultIfEmpty-separator Otherwise it will append the standard-separator The separator is appended usingappend(char)
.- Parameters:
standard
- the separator if builder is not emptydefaultIfEmpty
- the separator if builder is empty- Returns:
- this, to enable chaining
- Since:
- 2.5
-
appendSeparator
Appends a separator to the builder if the loop index is greater than zero. Appending a null separator will have no effect. The separator is appended usingappend(String)
.This method is useful for adding a separator each time around the loop except the first.
for (int i = 0; i < list.size(); i++) { appendSeparator(",", i); append(list.get(i)); }
Note that for this simple example, you should useappendWithSeparators(Collection, String)
.- Parameters:
separator
- the separator to use, null means no separatorloopIndex
- the loop index- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendSeparator
Appends a separator to the builder if the loop index is greater than zero. The separator is appended usingappend(char)
.This method is useful for adding a separator each time around the loop except the first.
for (int i = 0; i < list.size(); i++) { appendSeparator(",", i); append(list.get(i)); }
Note that for this simple example, you should useappendWithSeparators(Collection, String)
.- Parameters:
separator
- the separator to useloopIndex
- the loop index- Returns:
- this, to enable chaining
- Since:
- 2.3
-
appendPadding
Appends the pad character to the builder the specified number of times.- Parameters:
length
- the length to append, negative means no appendpadChar
- the character to append- Returns:
- this, to enable chaining
-
appendFixedWidthPadLeft
Appends an object to the builder padding on the left to a fixed width. ThetoString
of the object is used. If the object is larger than the length, the left hand side is lost. If the object is null, the null text value is used.- Parameters:
obj
- the object to append, null uses null textwidth
- the fixed field width, zero or negative has no effectpadChar
- the pad character to use- Returns:
- this, to enable chaining
-
appendFixedWidthPadLeft
Appends an object to the builder padding on the left to a fixed width. TheString.valueOf
of theint
value is used. If the formatted value is larger than the length, the left hand side is lost.- Parameters:
value
- the value to appendwidth
- the fixed field width, zero or negative has no effectpadChar
- the pad character to use- Returns:
- this, to enable chaining
-
appendFixedWidthPadRight
Appends an object to the builder padding on the right to a fixed length. ThetoString
of the object is used. If the object is larger than the length, the right hand side is lost. If the object is null, null text value is used.- Parameters:
obj
- the object to append, null uses null textwidth
- the fixed field width, zero or negative has no effectpadChar
- the pad character to use- Returns:
- this, to enable chaining
-
appendFixedWidthPadRight
Appends an object to the builder padding on the right to a fixed length. TheString.valueOf
of theint
value is used. If the object is larger than the length, the right hand side is lost.- Parameters:
value
- the value to appendwidth
- the fixed field width, zero or negative has no effectpadChar
- the pad character to use- Returns:
- this, to enable chaining
-
insert
Inserts the string representation of an object into this builder. Inserting null will use the stored null text value.- Parameters:
index
- the index to add at, must be validobj
- the object to insert- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
insert
Inserts the string into this builder. Inserting null will use the stored null text value.- Parameters:
index
- the index to add at, must be validstr
- the string to insert- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
insert
Inserts the character array into this builder. Inserting null will use the stored null text value.- Parameters:
index
- the index to add at, must be validchars
- the char array to insert- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
insert
Inserts part of the character array into this builder. Inserting null will use the stored null text value.- Parameters:
index
- the index to add at, must be validchars
- the char array to insertoffset
- the offset into the character array to start at, must be validlength
- the length of the character array part to copy, must be positive- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if any index is invalid
-
insert
Inserts the value into this builder.- Parameters:
index
- the index to add at, must be validvalue
- the value to insert- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
insert
Inserts the value into this builder.- Parameters:
index
- the index to add at, must be validvalue
- the value to insert- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
insert
Inserts the value into this builder.- Parameters:
index
- the index to add at, must be validvalue
- the value to insert- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
insert
Inserts the value into this builder.- Parameters:
index
- the index to add at, must be validvalue
- the value to insert- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
insert
Inserts the value into this builder.- Parameters:
index
- the index to add at, must be validvalue
- the value to insert- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
insert
Inserts the value into this builder.- Parameters:
index
- the index to add at, must be validvalue
- the value to insert- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
delete
Deletes the characters between the two specified indices.- Parameters:
startIndex
- the start index, inclusive, must be validendIndex
- the end index, exclusive, must be valid except that if too large it is treated as end of string- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
deleteAll
Deletes the character wherever it occurs in the builder.- Parameters:
ch
- the character to delete- Returns:
- this, to enable chaining
-
deleteFirst
Deletes the character wherever it occurs in the builder.- Parameters:
ch
- the character to delete- Returns:
- this, to enable chaining
-
deleteAll
Deletes the string wherever it occurs in the builder.- Parameters:
str
- the string to delete, null causes no action- Returns:
- this, to enable chaining
-
deleteFirst
Deletes the string wherever it occurs in the builder.- Parameters:
str
- the string to delete, null causes no action- Returns:
- this, to enable chaining
-
deleteAll
Deletes all parts of the builder that the matcher matches.Matchers can be used to perform advanced deletion behaviour. For example you could write a matcher to delete all occurances where the character 'a' is followed by a number.
- Parameters:
matcher
- the matcher to use to find the deletion, null causes no action- Returns:
- this, to enable chaining
-
deleteFirst
Deletes the first match within the builder using the specified matcher.Matchers can be used to perform advanced deletion behaviour. For example you could write a matcher to delete where the character 'a' is followed by a number.
- Parameters:
matcher
- the matcher to use to find the deletion, null causes no action- Returns:
- this, to enable chaining
-
replace
Replaces a portion of the string builder with another string. The length of the inserted string does not have to match the removed length.- Parameters:
startIndex
- the start index, inclusive, must be validendIndex
- the end index, exclusive, must be valid except that if too large it is treated as end of stringreplaceStr
- the string to replace with, null means delete range- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
replaceAll
Replaces the search character with the replace character throughout the builder.- Parameters:
search
- the search characterreplace
- the replace character- Returns:
- this, to enable chaining
-
replaceFirst
Replaces the first instance of the search character with the replace character in the builder.- Parameters:
search
- the search characterreplace
- the replace character- Returns:
- this, to enable chaining
-
replaceAll
Replaces the search string with the replace string throughout the builder.- Parameters:
searchStr
- the search string, null causes no action to occurreplaceStr
- the replace string, null is equivalent to an empty string- Returns:
- this, to enable chaining
-
replaceFirst
Replaces the first instance of the search string with the replace string.- Parameters:
searchStr
- the search string, null causes no action to occurreplaceStr
- the replace string, null is equivalent to an empty string- Returns:
- this, to enable chaining
-
replaceAll
Replaces all matches within the builder with the replace string.Matchers can be used to perform advanced replace behaviour. For example you could write a matcher to replace all occurances where the character 'a' is followed by a number.
- Parameters:
matcher
- the matcher to use to find the deletion, null causes no actionreplaceStr
- the replace string, null is equivalent to an empty string- Returns:
- this, to enable chaining
-
replaceFirst
Replaces the first match within the builder with the replace string.Matchers can be used to perform advanced replace behaviour. For example you could write a matcher to replace where the character 'a' is followed by a number.
- Parameters:
matcher
- the matcher to use to find the deletion, null causes no actionreplaceStr
- the replace string, null is equivalent to an empty string- Returns:
- this, to enable chaining
-
replace
public StrBuilder replace(StrMatcher matcher, String replaceStr, int startIndex, int endIndex, int replaceCount) Advanced search and replaces within the builder using a matcher.Matchers can be used to perform advanced behaviour. For example you could write a matcher to delete all occurances where the character 'a' is followed by a number.
- Parameters:
matcher
- the matcher to use to find the deletion, null causes no actionreplaceStr
- the string to replace the match with, null is a deletestartIndex
- the start index, inclusive, must be validendIndex
- the end index, exclusive, must be valid except that if too large it is treated as end of stringreplaceCount
- the number of times to replace, -1 for replace all- Returns:
- this, to enable chaining
- Throws:
IndexOutOfBoundsException
- if start index is invalid
-
reverse
Reverses the string builder placing each character in the opposite index.- Returns:
- this, to enable chaining
-
trim
Trims the builder by removing characters less than or equal to a space from the beginning and end.- Returns:
- this, to enable chaining
-
startsWith
Checks whether this builder starts with the specified string.Note that this method handles null input quietly, unlike String.
- Parameters:
str
- the string to search for, null returns false- Returns:
- true if the builder starts with the string
-
endsWith
Checks whether this builder ends with the specified string.Note that this method handles null input quietly, unlike String.
- Parameters:
str
- the string to search for, null returns false- Returns:
- true if the builder ends with the string
-
substring
Extracts a portion of this string builder as a string.- Parameters:
start
- the start index, inclusive, must be valid- Returns:
- the new string
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
substring
Extracts a portion of this string builder as a string.Note: This method treats an endIndex greater than the length of the builder as equal to the length of the builder, and continues without error, unlike StringBuffer or String.
- Parameters:
startIndex
- the start index, inclusive, must be validendIndex
- the end index, exclusive, must be valid except that if too large it is treated as end of string- Returns:
- the new string
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
leftString
Extracts the leftmost characters from the string builder without throwing an exception.This method extracts the left
length
characters from the builder. If this many characters are not available, the whole builder is returned. Thus the returned string may be shorter than the length requested.- Parameters:
length
- the number of characters to extract, negative returns empty string- Returns:
- the new string
-
rightString
Extracts the rightmost characters from the string builder without throwing an exception.This method extracts the right
length
characters from the builder. If this many characters are not available, the whole builder is returned. Thus the returned string may be shorter than the length requested.- Parameters:
length
- the number of characters to extract, negative returns empty string- Returns:
- the new string
-
midString
Extracts some characters from the middle of the string builder without throwing an exception.This method extracts
length
characters from the builder at the specified index. If the index is negative it is treated as zero. If the index is greater than the builder size, it is treated as the builder size. If the length is negative, the empty string is returned. If insufficient characters are available in the builder, as much as possible is returned. Thus the returned string may be shorter than the length requested.- Parameters:
index
- the index to start at, negative means zerolength
- the number of characters to extract, negative returns empty string- Returns:
- the new string
-
contains
public boolean contains(char ch) Checks if the string builder contains the specified char.- Parameters:
ch
- the character to find- Returns:
- true if the builder contains the character
-
contains
Checks if the string builder contains the specified string.- Parameters:
str
- the string to find- Returns:
- true if the builder contains the string
-
contains
Checks if the string builder contains a string matched using the specified matcher.Matchers can be used to perform advanced searching behaviour. For example you could write a matcher to search for the character 'a' followed by a number.
- Parameters:
matcher
- the matcher to use, null returns -1- Returns:
- true if the matcher finds a match in the builder
-
indexOf
public int indexOf(char ch) Searches the string builder to find the first reference to the specified char.- Parameters:
ch
- the character to find- Returns:
- the first index of the character, or -1 if not found
-
indexOf
public int indexOf(char ch, int startIndex) Searches the string builder to find the first reference to the specified char.- Parameters:
ch
- the character to findstartIndex
- the index to start at, invalid index rounded to edge- Returns:
- the first index of the character, or -1 if not found
-
indexOf
Searches the string builder to find the first reference to the specified string.Note that a null input string will return -1, whereas the JDK throws an exception.
- Parameters:
str
- the string to find, null returns -1- Returns:
- the first index of the string, or -1 if not found
-
indexOf
Searches the string builder to find the first reference to the specified string starting searching from the given index.Note that a null input string will return -1, whereas the JDK throws an exception.
- Parameters:
str
- the string to find, null returns -1startIndex
- the index to start at, invalid index rounded to edge- Returns:
- the first index of the string, or -1 if not found
-
indexOf
Searches the string builder using the matcher to find the first match.Matchers can be used to perform advanced searching behaviour. For example you could write a matcher to find the character 'a' followed by a number.
- Parameters:
matcher
- the matcher to use, null returns -1- Returns:
- the first index matched, or -1 if not found
-
indexOf
Searches the string builder using the matcher to find the first match searching from the given index.Matchers can be used to perform advanced searching behaviour. For example you could write a matcher to find the character 'a' followed by a number.
- Parameters:
matcher
- the matcher to use, null returns -1startIndex
- the index to start at, invalid index rounded to edge- Returns:
- the first index matched, or -1 if not found
-
lastIndexOf
public int lastIndexOf(char ch) Searches the string builder to find the last reference to the specified char.- Parameters:
ch
- the character to find- Returns:
- the last index of the character, or -1 if not found
-
lastIndexOf
public int lastIndexOf(char ch, int startIndex) Searches the string builder to find the last reference to the specified char.- Parameters:
ch
- the character to findstartIndex
- the index to start at, invalid index rounded to edge- Returns:
- the last index of the character, or -1 if not found
-
lastIndexOf
Searches the string builder to find the last reference to the specified string.Note that a null input string will return -1, whereas the JDK throws an exception.
- Parameters:
str
- the string to find, null returns -1- Returns:
- the last index of the string, or -1 if not found
-
lastIndexOf
Searches the string builder to find the last reference to the specified string starting searching from the given index.Note that a null input string will return -1, whereas the JDK throws an exception.
- Parameters:
str
- the string to find, null returns -1startIndex
- the index to start at, invalid index rounded to edge- Returns:
- the last index of the string, or -1 if not found
-
lastIndexOf
Searches the string builder using the matcher to find the last match.Matchers can be used to perform advanced searching behaviour. For example you could write a matcher to find the character 'a' followed by a number.
- Parameters:
matcher
- the matcher to use, null returns -1- Returns:
- the last index matched, or -1 if not found
-
lastIndexOf
Searches the string builder using the matcher to find the last match searching from the given index.Matchers can be used to perform advanced searching behaviour. For example you could write a matcher to find the character 'a' followed by a number.
- Parameters:
matcher
- the matcher to use, null returns -1startIndex
- the index to start at, invalid index rounded to edge- Returns:
- the last index matched, or -1 if not found
-
asTokenizer
Creates a tokenizer that can tokenize the contents of this builder.This method allows the contents of this builder to be tokenized. The tokenizer will be setup by default to tokenize on space, tab, newline and formfeed (as per StringTokenizer). These values can be changed on the tokenizer class, before retrieving the tokens.
The returned tokenizer is linked to this builder. You may intermix calls to the buider and tokenizer within certain limits, however there is no synchronization. Once the tokenizer has been used once, it must be
reset
to pickup the latest changes in the builder. For example:StrBuilder b = new StrBuilder(); b.append("a b "); StrTokenizer t = b.asTokenizer(); String[] tokens1 = t.getTokenArray(); // returns a,b b.append("c d "); String[] tokens2 = t.getTokenArray(); // returns a,b (c and d ignored) t.reset(); // reset causes builder changes to be picked up String[] tokens3 = t.getTokenArray(); // returns a,b,c,d
In addition to simply intermixing appends and tokenization, you can also call the set methods on the tokenizer to alter how it tokenizes. Just remember to call reset when you want to pickup builder changes.Calling
StrTokenizer.reset(String)
orStrTokenizer.reset(char[])
with a non-null value will break the link with the builder.- Returns:
- a tokenizer that is linked to this builder
-
asReader
Gets the contents of this builder as a Reader.This method allows the contents of the builder to be read using any standard method that expects a Reader.
To use, simply create a
StrBuilder
, populate it with data, callasReader
, and then read away.The internal character array is shared between the builder and the reader. This allows you to append to the builder after creating the reader, and the changes will be picked up. Note however, that no synchronization occurs, so you must perform all operations with the builder and the reader in one thread.
The returned reader supports marking, and ignores the flush method.
- Returns:
- a reader that reads from this builder
-
asWriter
Gets this builder as a Writer that can be written to.This method allows you to populate the contents of the builder using any standard method that takes a Writer.
To use, simply create a
StrBuilder
, callasWriter
, and populate away. The data is available at any time using the methods of theStrBuilder
.The internal character array is shared between the builder and the writer. This allows you to intermix calls that append to the builder and write using the writer and the changes will be occur correctly. Note however, that no synchronization occurs, so you must perform all operations with the builder and the writer in one thread.
The returned writer ignores the close and flush methods.
- Returns:
- a writer that populates this builder
-
equalsIgnoreCase
Checks the contents of this builder against another to see if they contain the same character content ignoring case.- Parameters:
other
- the object to check, null returns false- Returns:
- true if the builders contain the same characters in the same order
-
equals
Checks the contents of this builder against another to see if they contain the same character content.- Parameters:
other
- the object to check, null returns false- Returns:
- true if the builders contain the same characters in the same order
-
equals
Checks the contents of this builder against another to see if they contain the same character content. -
hashCode
public int hashCode()Gets a suitable hash code for this builder. -
toString
Gets a String version of the string builder, creating a new instance each time the method is called.Note that unlike StringBuffer, the string version returned is independent of the string builder.
-
toStringBuffer
Gets a StringBuffer version of the string builder, creating a new instance each time the method is called.- Returns:
- the builder as a StringBuffer
-
clone
Clone this object.- Overrides:
clone
in classObject
- Returns:
- a clone of this object
- Throws:
CloneNotSupportedException
- if clone is not supported- Since:
- 2.6
-
validateRange
protected int validateRange(int startIndex, int endIndex) Validates parameters defining a range of the builder.- Parameters:
startIndex
- the start index, inclusive, must be validendIndex
- the end index, exclusive, must be valid except that if too large it is treated as end of string- Returns:
- the new string
- Throws:
IndexOutOfBoundsException
- if the index is invalid
-
validateIndex
protected void validateIndex(int index) Validates parameters defining a single index in the builder.- Parameters:
index
- the index, must be valid- Throws:
IndexOutOfBoundsException
- if the index is invalid
-