I've just coded up in the Drools 3.0 rule language. Bindings are
specified locally and application data is specified as arguments to the
rule. This example shows a converted Miss Manners, so application data
is not used:
public class Guest {
private String name;
private char sex;
private String hobby;
...
}
public class LastSeat {
private int seat;
...
}
public class Seating {
private int id;
private int pid;
private int leftSeat;
private int rightSeat;
private String leftName;
private String rightName;
private boolean pathDone;
...
}
public class Path {
private int id;
private String name;
private int seat;
...
}
public class Chosen {
private int id;
private String name;
private String hobby;
...
}
public class Count {
private int value;
...
}
rule assignFirstSeat() {
Context context;
when {
context : Context( state == Context.START_UP )
Guest( guestName:name )
count : Count(countValue:value)
} then {
drools.assert( new Seating( 1, guestName, 2, guestName,
countValue, 0, true ) );
drools.assert( new Path( countValue, guestName, 1 ) );
count.setCount( countValue + 1 );
ystem.out.println( "seat 1 " + guestName + " );
context.setPath( Context.ASSIGN_SEATS );
}
}
rule makePath() {
Context context;
int id, pid, leftSeat, rightSeat;
String pathName;
when {
context : Context( state == Context.MAKE_PATH )
Seat( id:id, pid:pid )
Path( id == pid, pathName:name, pathSeat:seat )
(not Path( id == id, name == pathName )
} else {
drools.assert( new Path( id, pathName, pathSeat ) );
}
}
rule findSeating() {
Context context;
int id, pid, leftSeat, rightSeat;
String leftSeatName, rightSeatName, leftGuestName, rightGuestHobby;
when {
context : Context( state == Context.START )
Seating( id:id, pid:pid, leftSeat:leftSeat, leftSeatName:leftName,
rightSeat:rightSeat, rightSeatName:rightName, pathDone ==
true )
Guest( name == rightSeatName, rightGuestSex:sex,
rightGuestHobby:hobby )
Guest( leftGuestName:name , sex != rightGuestSex, hobby ==
rightGuestHobby )
count : Count(countValue:value)
not ( Path( id == id, name == leftGuestName) )
not ( Chosen( id == id, name == leftGuestName, hobby ==
rightGuestHobby) )
} then {
int newSeat = rightSeat + 1;
drools.assert( new Seating( rightSeat, rightSeatName,
leftGuestName, newSeat, countValue, id, false );
drools.assert( new Path( countValue, leftGuestName, newSeat );
drools.assert( new Chosen( id, leftGuestName, rightGuestHobby ) );
System.out.println( "seat " + rightSeat + " " + rightSeatName +
" " + leftGuestName );
count.setCount( countValue + 1 );
context.setPath( Context.MAKE_PATH );
}
}
rule pathDone() {
Context context;
Seat seat;
when {
context : Context( state == Context.MAKE_PATH )
seating : Seating( pathDone == false )
} then {
seating.setPathDone( true );
context.setName( Context.CHECK_DONE );
}
}
rule areWeDoneYet() {
Context context;
when {
context : Context( state == Context.CHECK_DONE )
LastSeat( lastSeat: seat )
Seating( seat == lastSeat )
} then {
context.setName( Context.PRINT_RESULTS );
}
}
rule continueProcessing {
Context context;
when {
context : Context( state == Context.CHECK_DONE )
} then {
context.setName( Context.ASSIGN_SEATS);
}
}
rule printResults() {
Context context;
when {
context : Context( state == Context.PRINT_RESULTS )
Seating( id: id, rightSeat:rightSeat )
LastSeat( seat == rightSeat )
path:Path( id == id, pathName:name, pathSeat:seat)
} then {
System.out.println( "name : '" + pathName + "' seat : '" +
pathSeat + "'" );
}
}
rule allDone {
Context context;
when {
context : Context( state == Context.PRINT_RESULTS )
} then {
System.out.println( "rule all done: Condition context
print_results" );
}
}
