public Context(Context context, Agent agent) {
job = context.job;
activation = context.activation;
letBindings = context.letBindings;
myself = context.agent;
agentBit = agent.agentBit();
}
public Object callReporterProcedure(Activation newActivation) {
boolean oldInReporterProcedure = inReporterProcedure;
Command command = null;
inReporterProcedure = true; // so use of "ask" will create an exclusive job
activation = newActivation;
ip = 0;
try {
do {
command = activation.procedure().code()[ip];
if ((agentBit & command.agentBits) == 0) {
command.throwAgentClassException(this, agent.kind());
}
command.perform(this);
if (command.world.comeUpForAir) {
comeUpForAir(command);
}
} while (!finished && job.result == null);
} catch (NonLocalExit$ e) {
// do nothing
} catch (LogoException ex) {
EngineException.rethrow(ex, this, command);
} finally {
inReporterProcedure = oldInReporterProcedure;
}
ip = activation.returnAddress();
activation = activation.parent();
Object result = job.result;
job.result = null;
return result;
}
// This constructor is used when a Context spawns a Job which
// in turn spawns Contexts, such as with _ask. - ST 6/12/06
public Context(Job job, Agent agent, int ip, Activation activation) {
this.job = job;
this.agent = agent;
if (agent != null) {
agentBit = agent.agentBit();
}
this.ip = ip;
this.activation = activation;
}
// this method runs until the context is finished
void runExclusive() {
if (agent.id == -1) // is our agent dead?
{
finished = true;
return;
}
Command command = null;
try {
do {
command = activation.procedure().code()[ip];
if ((agentBit & command.agentBits) == 0) {
command.throwAgentClassException(this, agent.kind());
}
command.perform(this);
if (command.world.comeUpForAir) {
comeUpForAir(command);
}
} while (!finished);
} catch (LogoException ex) {
EngineException.rethrow(ex, this, command);
}
}
// this method runs only until a command switches
void stepConcurrent() {
if (agent.id == -1) // is our agent dead?
{
finished = true;
return;
}
Command command = null;
try {
do {
command = activation.procedure().code()[ip];
if ((agentBit & command.agentBits) == 0) {
command.throwAgentClassException(this, agent.kind());
}
command.perform(this);
if (command.world.comeUpForAir) {
comeUpForAir(command);
}
} while (!command.switches && !finished);
} catch (LogoException ex) {
EngineException.rethrow(ex, this, command);
} catch (StackOverflowError ex) {
throw new EngineException(this, "stack overflow (recursion too deep)");
}
}