Re: Object retval = (Object)bindings.get(var); // why not OK?

From:
Mark Space <markspace@sbc.global.net>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 23 Aug 2007 19:12:04 GMT
Message-ID:
<8_kzi.34599$2v1.32582@newssvr14.news.prodigy.net>
metaperl wrote:

I'm wondering why I cannot simply cast the return result of .get() to
satisfy the compiler expectation that the method return an object.
Instead I have to assign the result of .get() to a variable and then
return that.

package redick;

import java.util.*;
import java.util.Iterator;

public class Environment {
    /*
     * map from a variable name to an Object - which may be a datum or a
     * procedure
     */
    public Map<String,Object> bindings = new HashMap<String, Object>();
    public Environment parent;

    public void put(String var, Object value) {
        bindings.put(var, value);
    }
    public Object get(String var) {

        Object retval = bindings.get(var); // cast not enough
        /* Cannot comment this section out */
        if (retval == null) {
            return (Object)null;
        } else {
            return retval;
        }
        /* End required section */
        
return retval;
    }

    public String toString() { return bindings.toString(); }

}


As Lew mentioned, you just need to add the "return retval;" (see above)
to the code snippet. Then you should be able to comment out the
indicated section.

Just one of the late-night programmer-didn't-see-it things, I guess... ^_^

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