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java.lang
public final class: StringBuilder [javadoc | source]
java.lang.Object
   java.lang.AbstractStringBuilder
      java.lang.StringBuilder

All Implemented Interfaces:
    CharSequence, java$io$Serializable, Appendable

A mutable sequence of characters. This class provides an API compatible with StringBuffer, but with no guarantee of synchronization. This class is designed for use as a drop-in replacement for StringBuffer in places where the string buffer was being used by a single thread (as is generally the case). Where possible, it is recommended that this class be used in preference to StringBuffer as it will be faster under most implementations.

The principal operations on a StringBuilder are the append and insert methods, which are overloaded so as to accept data of any type. Each effectively converts a given datum to a string and then appends or inserts the characters of that string to the string builder. The append method always adds these characters at the end of the builder; the insert method adds the characters at a specified point.

For example, if z refers to a string builder object whose current contents are "start", then the method call z.append("le") would cause the string builder to contain "startle", whereas z.insert(4, "le") would alter the string builder to contain "starlet".

In general, if sb refers to an instance of a StringBuilder, then sb.append(x) has the same effect as sb.insert(sb.length(), x). Every string builder has a capacity. As long as the length of the character sequence contained in the string builder does not exceed the capacity, it is not necessary to allocate a new internal buffer. If the internal buffer overflows, it is automatically made larger.

Instances of StringBuilder are not safe for use by multiple threads. If such synchronization is required then it is recommended that java.lang.StringBuffer be used.

Field Summary
static final  long serialVersionUID    use serialVersionUID for interoperability 
Fields inherited from java.lang.AbstractStringBuilder:
value,  count
Constructor:
 public StringBuilder() 
 public StringBuilder(int capacity) 
 public StringBuilder(String str) 
    Constructs a string builder initialized to the contents of the specified string. The initial capacity of the string builder is 16 plus the length of the string argument.
    Parameters:
    str - the initial contents of the buffer.
    Throws:
    NullPointerException - if str is null
 public StringBuilder(CharSequence seq) 
    Constructs a string builder that contains the same characters as the specified CharSequence. The initial capacity of the string builder is 16 plus the length of the CharSequence argument.
    Parameters:
    seq - the sequence to copy.
    Throws:
    NullPointerException - if seq is null
Method from java.lang.StringBuilder Summary:
append,   append,   append,   append,   append,   append,   append,   append,   append,   append,   append,   append,   append,   appendCodePoint,   delete,   deleteCharAt,   indexOf,   indexOf,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   lastIndexOf,   lastIndexOf,   replace,   reverse,   toString
Methods from java.lang.AbstractStringBuilder:
append,   append,   append,   append,   append,   append,   append,   append,   append,   append,   append,   append,   append,   appendCodePoint,   capacity,   charAt,   codePointAt,   codePointBefore,   codePointCount,   delete,   deleteCharAt,   ensureCapacity,   expandCapacity,   getChars,   getValue,   indexOf,   indexOf,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   insert,   lastIndexOf,   lastIndexOf,   length,   offsetByCodePoints,   replace,   reverse,   setCharAt,   setLength,   subSequence,   substring,   substring,   toString,   trimToSize
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.lang.StringBuilder Detail:
 public StringBuilder append(Object obj) 
 public StringBuilder append(String str) 
 public StringBuilder append(StringBuffer sb) 
    Appends the specified StringBuffer to this sequence.

    The characters of the StringBuffer argument are appended, in order, to this sequence, increasing the length of this sequence by the length of the argument. If sb is null, then the four characters "null" are appended to this sequence.

    Let n be the length of this character sequence just prior to execution of the append method. Then the character at index k in the new character sequence is equal to the character at index k in the old character sequence, if k is less than n; otherwise, it is equal to the character at index k-n in the argument sb.

 public StringBuilder append(CharSequence s) 
 public StringBuilder append(char[] str) 
 public StringBuilder append(boolean b) 
 public StringBuilder append(char c) 
 public StringBuilder append(int i) 
 public StringBuilder append(long lng) 
 public StringBuilder append(float f) 
 public StringBuilder append(double d) 
 public StringBuilder append(CharSequence s,
    int start,
    int end) 
 public StringBuilder append(char[] str,
    int offset,
    int len) 
 public StringBuilder appendCodePoint(int codePoint) 
 public StringBuilder delete(int start,
    int end) 
 public StringBuilder deleteCharAt(int index) 
 public int indexOf(String str) 
 public int indexOf(String str,
    int fromIndex) 
 public StringBuilder insert(int offset,
    Object obj) 
 public StringBuilder insert(int offset,
    String str) 
 public StringBuilder insert(int offset,
    char[] str) 
 public StringBuilder insert(int dstOffset,
    CharSequence s) 
 public StringBuilder insert(int offset,
    boolean b) 
 public StringBuilder insert(int offset,
    char c) 
 public StringBuilder insert(int offset,
    int i) 
 public StringBuilder insert(int offset,
    long l) 
 public StringBuilder insert(int offset,
    float f) 
 public StringBuilder insert(int offset,
    double d) 
 public StringBuilder insert(int index,
    char[] str,
    int offset,
    int len) 
 public StringBuilder insert(int dstOffset,
    CharSequence s,
    int start,
    int end) 
 public int lastIndexOf(String str) 
 public int lastIndexOf(String str,
    int fromIndex) 
 public StringBuilder replace(int start,
    int end,
    String str) 
 public StringBuilder reverse() 
 public String toString()