/**
* Copyright (C) 2010 dennis zhuang (killme2008@gmail.com)
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
**/
package com.googlecode.aviator.runtime.function.seq;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import com.googlecode.aviator.exception.ExpressionRuntimeException;
import com.googlecode.aviator.runtime.function.FunctionUtils;
import com.googlecode.aviator.runtime.type.AviatorFunction;
import com.googlecode.aviator.runtime.type.AviatorJavaType;
import com.googlecode.aviator.runtime.type.AviatorObject;
import com.googlecode.aviator.runtime.type.AviatorRuntimeJavaType;
/**
* filter(seq,predicate) to filter seq by predicate
*
* @author dennis
*
*/
public class SeqFilterFunction implements AviatorFunction {
@SuppressWarnings("unchecked")
public AviatorObject call(Map<String, Object> env, AviatorObject... args) {
if (args.length != 2) {
throw new IllegalArgumentException("filter(seq,pred)");
}
Object first = args[0].getValue(env);
AviatorFunction fun = FunctionUtils.getFunction(1, args, env, 1);
if (fun == null) {
throw new ExpressionRuntimeException("There is no function named " + ((AviatorJavaType) args[1]).getName());
}
if (first == null) {
throw new NullPointerException("null seq");
}
Class<?> clazz = first.getClass();
if (Collection.class.isAssignableFrom(clazz)) {
Collection result = null;
try {
result = (Collection) clazz.newInstance();
}
catch (Throwable t) {
// ignore
result = new ArrayList();
}
for (Object obj : (Collection<?>) first) {
if (fun.call(env, new AviatorRuntimeJavaType(obj)).booleanValue(env)) {
result.add(obj);
}
}
return new AviatorRuntimeJavaType(result);
}
else if (clazz.isArray()) {
Object[] seq = (Object[]) first;
List result = new ArrayList();
for (Object obj : seq) {
if (fun.call(env, new AviatorRuntimeJavaType(obj)).booleanValue(env)) {
result.add(obj);
}
}
return new AviatorRuntimeJavaType(result.toArray());
}
else {
throw new IllegalArgumentException(args[0].desc(env) + " is not a seq");
}
}
public String getName() {
return "filter";
}
}