package jp.ac.kobe_u.cs.prolog.builtin;
import java.lang.reflect.Field;
import jp.ac.kobe_u.cs.prolog.lang.IllegalTypeException;
import jp.ac.kobe_u.cs.prolog.lang.JavaException;
import jp.ac.kobe_u.cs.prolog.lang.JavaObjectTerm;
import jp.ac.kobe_u.cs.prolog.lang.JavaPredicate;
import jp.ac.kobe_u.cs.prolog.lang.PInstantiationException;
import jp.ac.kobe_u.cs.prolog.lang.Predicate;
import jp.ac.kobe_u.cs.prolog.lang.Prolog;
import jp.ac.kobe_u.cs.prolog.lang.SymbolTerm;
import jp.ac.kobe_u.cs.prolog.lang.Term;
/**
* <code>java_get_declared_field0/3</code>
*
* @author Mutsunori Banbara (banbara@kobe-u.ac.jp)
* @author Naoyuki Tamura (tamura@kobe-u.ac.jp)
* @version 1.1
*/
public class PRED_java_get_declared_field0_3 extends JavaPredicate {
/**
*
*/
private static final long serialVersionUID = 1096911934846227514L;
private Term arg1, arg2, arg3;
public PRED_java_get_declared_field0_3(Term a1, Term a2, Term a3,
Predicate cont) {
arg1 = a1;
arg2 = a2;
arg3 = a3;
this.cont = cont;
}
public PRED_java_get_declared_field0_3() {
}
@Override
public void setArgument(Term[] args, Predicate cont) {
arg1 = args[0];
arg2 = args[1];
arg3 = args[2];
this.cont = cont;
}
@Override
public int arity() {
return 3;
}
@Override
public String toString() {
return "java_get_declared_field0(" + arg1 + "," + arg2 + "," + arg3
+ ")";
}
@Override
public Predicate exec(Prolog engine) {
engine.setB0();
Term a1, a2, a3;
a1 = arg1;
a2 = arg2;
a3 = arg3;
Class clazz = null;
Object instance = null;
Field field = null;
Object value = null;
// 3rd. argument (unbound variable)
a3 = a3.dereference();
if (!a3.isVariable()) {
throw new IllegalTypeException(this, 3, "variable", a3);
}
try {
// 1st. argument (atom or java term)
a1 = a1.dereference();
if (a1.isVariable()) {
throw new PInstantiationException(this, 1);
} else if (a1.isSymbol()) { // class
clazz = Class.forName(((SymbolTerm) a1).name());
} else if (a1.isJavaObject()) { // instance
instance = ((JavaObjectTerm) a1).object();
clazz = ((JavaObjectTerm) a1).getClazz();
} else {
throw new IllegalTypeException(this, 1, "atom_or_java", a1);
}
// 2nd. argument (atom)
a2 = a2.dereference();
if (a2.isVariable()) {
throw new PInstantiationException(this, 2);
} else if (!a2.isSymbol()) {
throw new IllegalTypeException(this, 2, "atom", a2);
}
field = clazz.getDeclaredField(((SymbolTerm) a2).name());
field.setAccessible(true);
value = field.get(instance);
// 3rd. argument
if (value == null) {
return cont;
}
if (!a3.unify(toPrologTerm(value), engine.trail)) {
return engine.fail();
}
return cont;
} catch (ClassNotFoundException e) { // Class.forName
throw new JavaException(this, 1, e);
} catch (NoSuchFieldException e) { // Class.getField(..)
throw new JavaException(this, 2, e);
} catch (SecurityException e) { // Class.getField(..)
throw new JavaException(this, 2, e);
} catch (NullPointerException e) { // Class.getField(..)
throw new JavaException(this, 2, e);
} catch (IllegalAccessException e) { // Field.get(..)
throw new JavaException(this, 2, e);
} catch (IllegalArgumentException e) { // Field.get(..)
throw new JavaException(this, 2, e);
}
}
private Term toPrologTerm(Object obj) {
if (Term.instanceOfTerm(obj)) {
return (Term) obj;
} else {
return new JavaObjectTerm(obj);
}
}
}