Application: gvSIG desktop

package org.gvsig.expressionevaluator.impl.function.programming;

import java.util.List;

import java.util.Map;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.ExpressionRuntimeException;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

import org.gvsig.tools.util.GetItem;

import org.gvsig.tools.util.GetItem64;

import org.gvsig.tools.util.GetItemByKey;

public class GetitemFunction extends AbstractFunction {

    public static final String NAME = "GETITEM";

    public GetitemFunction() {

        super(Function.GROUP_PROGRAMMING, 

            NAME, 

            Range.is(2),

            null,

            null,

            null,

            "Object",

            false

        );

    }

    @Override

    public boolean allowConstantFolding() {

        return false;

    }

    @Override

    public Object call(Interpreter interpreter, Object[] args) throws Exception {

        Object value;

        Object obj = getObject(args, 0);

        if( obj == null ) {

            throw new ExpressionRuntimeException("Null is not valid in "+NAME+" function.");

        }

        if( obj instanceof List ) {

            List l = ((List)obj);

            int index = getInt(args,1);

            if( index<0 ) {

                index = l.size() + index;

            }

            value = l.get(index);

        } else if( obj instanceof CharSequence ) {

            CharSequence s = (CharSequence)obj;

            int index = getInt(args,1);

            if( index<0 ) {

                index = s.length() + index;

            }

            value = s.subSequence(index, index+1);

        } else if( obj instanceof Map ) {

            Map m = (Map)obj;

            Object index = getObject(args,1);

            value = m.get(index);

        } else if( obj instanceof GetItem ) {

            GetItem l = (GetItem)obj;

            int index = getInt(args,1);

            value = l.get(index);

        } else if( obj instanceof GetItem64 ) {

            GetItem64 l = (GetItem64)obj;

            long index = getLong(args,1);

            value = l.get64(index);

        } else if( obj instanceof GetItemByKey ) {

            GetItemByKey l = (GetItemByKey)obj;

            Object key = getObject(args,1);

            value = l.get(key);

        } else {

            throw new ExpressionRuntimeException("The "+NAME+" function require a String, List or Map and a received a '"+obj.getClass().getSimpleName()+"'.");

        }

        return value;

    }

}