Helper OutInCount

Jan Burse, created Sep 15. 2018
package example04;
import jekpro.platform.headless.ToolkitLibrary;
import jekpro.tools.call.CallIn;
import jekpro.tools.call.Interpreter;
import jekpro.tools.call.InterpreterException;
import jekpro.tools.call.InterpreterMessage;
import jekpro.tools.term.AbstractTerm;
import jekpro.tools.term.Knowledgebase;
import jekpro.tools.term.TermCompound;
import jekpro.tools.term.TermVar;
import java.io.IOException;
import java.io.Writer;
/**
* <p>Java code for the Call-out Call-in Solution Counter example.</p>
* <p/>
* Warranty & Liability
* To the extent permitted by applicable law and unless explicitly
* otherwise agreed upon, XLOG Technologies GmbH makes no warranties
* regarding the provided information. XLOG Technologies GmbH assumes
* no liability that any problems might be solved with the information
* provided by XLOG Technologies GmbH.
* <p/>
* Rights & License
* All industrial property rights regarding the information - copyright
* and patent rights in particular - are the sole property of XLOG
* Technologies GmbH. If the company was not the originator of some
* excerpts, XLOG Technologies GmbH has at least obtained the right to
* reproduce, change and translate the information.
* <p/>
* Reproduction is restricted to the whole unaltered document. Reproduction
* of the information is only allowed for non-commercial uses. Selling,
* giving away or letting of the execution of the library is prohibited.
* The library can be distributed as part of your applications and libraries
* for execution provided this comment remains unchanged.
* <p/>
* Restrictions
* Only to be distributed with programs that add significant and primary
* functionality to the library. Not to be distributed with additional
* software intended to replace any components of the library.
* <p/>
* Trademarks
* Jekejeke is a registered trademark of XLOG Technologies GmbH.
*/
public class OutInCount {
/**
* <p>Foreign predicate to count solutions.</p>
*
* @param inter The call-in.
* @param goal The goal.
* @return The count.
* @throws InterpreterException Passed down from the goal.
* @throws InterpreterMessage Shit happens.
*/
public static int count(Interpreter inter, AbstractTerm goal)
throws InterpreterException, InterpreterMessage {
CallIn callin = inter.iterator(goal);
int count = 0;
while (callin.hasNext()) {
callin.next();
count++;
}
return count;
}
/**
* <p>Runtime library variant of executing the example.</p>
*
* @param args The command line arguments.
* @throws InterpreterException Exception in Jekejeke Prolog execution.
* @throws InterpreterMessage Message in Jekejeke Prolog execution.
* @throws IOException Problem writing to current output.
*/
public static void main(String[] args) throws InterpreterException,
InterpreterMessage, IOException {
Knowledgebase know = new Knowledgebase(ToolkitLibrary.DEFAULT);
Interpreter inter = know.iterable();
Knowledgebase.initKnowledgebase(inter);
Object foreignGoal = inter.parseTerm("use_package(foreign(" +
"jekpro/tools/call))");
inter.iterator(foreignGoal).next().close();
foreignGoal = inter.parseTerm("use_package(foreign(" +
"jekpro/tools/term))");
inter.iterator(foreignGoal).next().close();
foreignGoal = inter.parseTerm("foreign(employee/1, " +
"'example03.OutTable', employee('CallOut'))");
inter.iterator(foreignGoal).next().close();
foreignGoal = inter.parseTerm("foreign(count/2, " +
"'example04.OutInCount', count('Interpreter', 'AbstractTerm'))");
inter.iterator(foreignGoal).next().close();
TermVar employeeVar = new TermVar();
TermCompound employeeGoal = new TermCompound("employee", employeeVar);
TermVar countVar = new TermVar();
TermCompound countGoal = new TermCompound(inter, "count", employeeGoal, countVar);
Writer wr = (Writer) inter.getProperty(ToolkitLibrary.PROP_SYS_CUR_OUTPUT);
CallIn callin = inter.iterator(countGoal);
callin.next();
wr.write(inter.unparseTerm(0, countVar));
wr.write('\n');
wr.flush();
callin.close();
}
}

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