blob: dfb34c6b7b58a31c88578da28b4d679a06976eda [file] [log] [blame]
package com.googlecode.prolog_cafe.builtin;
import com.googlecode.prolog_cafe.exceptions.ExistenceException;
import com.googlecode.prolog_cafe.exceptions.IllegalDomainException;
import com.googlecode.prolog_cafe.exceptions.InternalException;
import com.googlecode.prolog_cafe.exceptions.PInstantiationException;
import com.googlecode.prolog_cafe.lang.*;
import java.util.Hashtable;
import java.util.Enumeration;
/**
<code>hash_keys/2</code><br>
@author Mutsunori Banbara (banbara@kobe-u.ac.jp)
@author Naoyuki Tamura (tamura@kobe-u.ac.jp)
@version 1.0
*/
public class PRED_hash_keys_2 extends Predicate.P2 {
public PRED_hash_keys_2(Term a1, Term a2, Operation cont) {
arg1 = a1;
arg2 = a2;
this.cont = cont;
}
public Operation exec(Prolog engine) {
engine.setB0();
Term a1, a2;
a1 = arg1;
a2 = arg2;
Object hash = null;
a1 = a1.dereference();
if (a1.isVariable()) {
throw new PInstantiationException(this, 1);
} else if (a1.isSymbol()) {
if (! engine.getHashManager().containsKey(a1))
throw new ExistenceException(this, 1, "hash", a1, "");
hash = ((JavaObjectTerm) engine.getHashManager().get(a1)).object();
} else if (a1.isJavaObject()) {
hash = ((JavaObjectTerm) a1).object();
} else {
throw new IllegalDomainException(this, 1, "hash_or_alias", a1);
}
if (! (hash instanceof HashtableOfTerm))
throw new InternalException(this + ": Hash is not HashtableOfTerm");
Term keys = Prolog.Nil;
for (Term t : ((HashtableOfTerm) hash).keySet())
keys = new ListTerm(t, keys);
if (! a2.unify(keys, engine.trail))
return engine.fail();
return cont;
}
}