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POConfused how to type comparator in another class
 

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    <p>I am trying to sort the values of two LinkedHashMap. I can compile it and run the code just fine, but it tells me to use -Xlint option during compiling because it is unsafe code. It has something to do with type casting stuff, but I am royally confused on how to do it. I got this class which I put inbedded in my class:</p> <pre><code>static class MyComparator implements Comparator { public int compare(Object obj1, Object obj2){ int result=0; Map.Entry e1 = (Map.Entry)obj1 ; Map.Entry e2 = (Map.Entry)obj2 ;//Sort based on values. Integer value1 = (Integer)e1.getValue(); Integer value2 = (Integer)e2.getValue(); if(value1.compareTo(value2)==0){ String word1=(String)e1.getKey(); String word2=(String)e2.getKey(); //Sort String in an alphabetical order result=word1.compareToIgnoreCase(word2); } else { //Sort values in a descending order result=value2.compareTo( value1 ); } return result; } } </code></pre> <p>I tried to call it in one of my functions with:</p> <pre><code>ArrayList myArrayList=new ArrayList(this.map_freq_by_date.entrySet()); Collections.sort(myArrayList, new MyComparator()); Iterator itr=myArrayList.iterator(); </code></pre> <p>Note: this.map_freq_by_date is defined as follows:</p> <pre><code>Map&lt;String,Integer&gt; map_freq_by_date = new LinkedHashMap&lt;String,Integer&gt;(); </code></pre> <p>The error I get with -Xlint option:</p> <pre><code>unchecked call to ArrayList(java.util.Collection&lt;? extends E&gt;) as a member of the raw type java.util.ArrayList ArrayList myArrayList=new ArrayList(this.map_freq_by_date.entrySet()); unchecked conversion found LogGrep.MyComparator required: java.util.Comparator(? super T&gt; Collections.sort(myArrayList, new MyComparator()); unchecked method invocation: &lt;T&gt;sort(java.util.List&lt;T&gt;,java.util.Comparator&lt;? super T&gt; in java.util.Collections is applied to (java.util.ArrayList,LogGrep.MyComparator) Collections.sort(myArrayList, new MyComparator()); </code></pre> <p>Help with how to fix these would be appreciated. I looked online and tried all kinds of things shown, but I can't seem to get it right.</p> <p>Note: if I put <code>ArrayList&lt;Object&gt; myArrayList = new ArrayList&lt;Object&gt;</code>... the error changes to:</p> <pre><code>unchecked method invocation &lt;T&gt;sort(java.util.List&lt;T&gt;,java.util.Comparator&lt;&gt; super T?) in java.util.Collections is applied ot (java.util.ArraList&lt;java.lang.Object&gt;,LogGrep.MyComparator) Collections.sort(myArrayList, new MyComparator()); </code></pre>
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    1. USSean Patrick Floyd
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    1. COIt did not list my definition of map_freq_by_date as I intended in the question above. It is defined as a LinkedHashMap<String,Integer>.
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