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POHow to avoid casting for wrapper objects in maps?
 

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  1. POHow to avoid casting for wrapper objects in maps?
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    <p>I have an interface FeatureValue which implements a function called pretty print.</p> <p>I have two classes right now that implement that interface: FeatureString and FeatureList (The lists in FeatureList contain strings). These classes are just wrapper that store a string and a list respectively and implement the pretty print function for their wrapped values.</p> <p>I have EnumMap which takes as keys some enums of type Feature (some which correspond to strings and some which correspond to lists). </p> <p>I originally made this interface so that I could just iterate over the Enums and pretty print them. But now I want to be able to get the value from the wrapper FeatureValue as well. </p> <p>Since I'm storing the enum map as <code>&lt;Feature, FeatureValue&gt;</code> , it doesn't know what type the wrapped value is so I have to cast when I get it. </p> <p>Is there a way to refactor my code so that I don't need to cast, but still retain the ability to just iterate over the Enums and print them without knowing the type?</p> <p>Enum</p> <pre><code>public enum Features { KIND("kind"), RULE("rule"), PROBLEM("problem"), private String name; Features(String name) { this.name = name; } public String getName() { return name; } } </code></pre> <p>Interface</p> <pre><code>public interface FeatureValue { public String prettyPrint(); } </code></pre> <p>List implementation (There's a similar one for FeatureString which I'll omit)</p> <pre><code>public class FeatureList implements FeatureValue { private final List&lt;String&gt; list; public FeatureList(List&lt;String&gt; list) { this.list = list; } @Override public String prettyPrint() { return Arrays.toString(list.toArray()); } public List&lt;String&gt; getList() { return list; } } </code></pre> <p>Casting code</p> <pre><code>for(String token: ((FeatureList) enumMap.get(Feature.particularFeatureThatCorrespondsToLists)).getValue()) doSomething(token); </code></pre> <p>There is a cast necessary since the map is parameterized for values of Feature, not FeatureList</p>
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    1. COCould we see some code? It looks like you're missing a few things, like what you're "storing the enum map as."
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      1. USLouis Wasserman
    2. COyea i just noticed, I fixed that missing part
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    3. COlemme add some code
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