Java Doc for Formattable.java in  » 6.0-JDK-Core » Collections-Jar-Zip-Logging-regex » java » util » Java Source Code / Java DocumentationJava Source Code and Java Documentation

 import java.nio.CharBuffer;
 import java.util.Formatter;
 import java.util.Formattable;
 import java.util.Locale;
 import static java.util.FormattableFlags.*;
 ...
 public class StockName implements Formattable {
 private String symbol, companyName, frenchCompanyName;
 public StockName(String symbol, String companyName,
 String frenchCompanyName) {
 ...
 }
 ...
 public void formatTo(Formatter fmt, int f, int width, int precision) {
 StringBuilder sb = new StringBuilder();
 // decide form of name 
 String name = companyName;
 if (fmt.locale().equals(Locale.FRANCE))
 name = frenchCompanyName;
 boolean alternate = (f & ALTERNATE) == ALTERNATE;
 boolean usesymbol = alternate || (precision != -1 && precision < 10);
 String out = (usesymbol ? symbol : name);
 // apply precision
 if (precision == -1 || out.length() < precision) {
 // write it all
 sb.append(out);
 } else {
 sb.append(out.substring(0, precision - 1)).append('*');
 }
 // apply width and justification
 int len = sb.length(); 
 if (len < width)
 for (int i = 0; i < width - len; i++)
 if ((f & LEFT_JUSTIFY) == LEFT_JUSTIFY)
 sb.append(' ');
 else
 sb.insert(0, ' ');
 fmt.format(sb.toString());
 }
 public String toString() {
 return String.format("%s - %s", symbol, companyName);
 }
 }
 

When used in conjunction with the java.util.Formatter , the above class produces the following output for various format strings.

 Formatter fmt = new Formatter();
 StockName sn = new StockName("HUGE", "Huge Fruit, Inc.",
 "Fruit Titanesque, Inc.");
 fmt.format("%s", sn);                   //   -> "Huge Fruit, Inc."
 fmt.format("%s", sn.toString());        //   -> "HUGE - Huge Fruit, Inc."
 fmt.format("%#s", sn);                  //   -> "HUGE"
 fmt.format("%-10.8s", sn);              //   -> "HUGE      "
 fmt.format("%.12s", sn);                //   -> "Huge Fruit,*"
 fmt.format(Locale.FRANCE, "%25s", sn);  //   -> "   Fruit Titanesque, Inc." 
 

Formattables are not necessarily safe for multithreaded access. Thread safety is optional and may be enforced by classes that extend and implement this interface.

Unless otherwise specified, passing a null argument to any method in this interface will cause a NullPointerException to be thrown.
version:
   1.10, 05/05/07
since:
   1.5