职责链模式chain

//Purpose.  Lots of client effort to manage a list of Processors

public class ChainBefore {

interface Image { String process(); }
static class IR implements Image { public String process() { return "IR"; } }
static class LS implements Image { public String process() { return "LS"; } }

static class Processor {
private static java.util.Random rn = new java.util.Random();
private static int nextId = 1;
private int id = nextId++;
public boolean handle( Image img ) {
   if (rn.nextInt(2) != 0) {
      System.out.println( "   Processor " + id + " is busy" );
      return false;
   }
   System.out.println( "Processor " + id + " - " + img.process() );
   return true;
}  }

public static void main( String[] args ) {
Image[] input = { new IR(), new IR(), new LS(), new IR(), new LS(), new LS() };
Processor[] procs = { new Processor(), new Processor(), new Processor() };
for (int i=0, j; i < input.length; i++) {
   j = 0;
   while ( ! procs[j].handle( input[i] ))
      j = (j+1) % procs.length;
}  }}