Performance - Inefficient use of keySet iterator instead of entrySet iterator

Question

This piece of code throws the error This method accesses the value of a Map entry, using a key that was retrieved from a keySet iterator. It is more efficient to use an iterator on the entrySet of the map, to avoid the Map.get(key) lookup. Kindly guide me how to rephrase it

if (docPropertiesMap != null) {
        Iterator<String> properties = docPropertiesMap.keySet().iterator();
        IDocProperty[] docProperties = new IDocProperty[docPropertiesMap
                .size()];
        int iArrIndex = 0;

        while (properties.hasNext()) {
            String strPropName = properties.next();
            String[] propValue = docPropertiesMap.get(strPropName);

            IDocProperty docProperty = (IDocProperty) FDMAFactory
                    .getDataObject("DocProperty");
            docProperty.setPropertyName(strPropName);
            docProperty.setArrPropertyValues(propValue);
            docProperties[iArrIndex++] = docProperty;
        }
        metadata.setArrDocProperties(docProperties);
        return metadata;
    }

Please have a look at the similar question: http://stackoverflow.com/questions/3870064/performance-considerations-for-keyset-and-entryset-of-map?rq=1 — vijay, Sep 25 '15 at 10:06

Tunaki · Accepted Answer · 2015-09-25T10:14:33.050

This is SonarQube warning coming from FindBugs.

You can rewrite your code like this:

if (docPropertiesMap != null) {
    IDocProperty[] docProperties = new IDocProperty[docPropertiesMap.size()];
    int iArrIndex = 0;

    for (Map.Entry<String, String[]> entry : docPropertiesMap.entrySet()) {
        String strPropName = entry.getKey();
        String[] propValue = entry.getValue();

        IDocProperty docProperty = (IDocProperty) FDMAFactory.getDataObject("DocProperty");
        docProperty.setPropertyName(strPropName);
        docProperty.setArrPropertyValues(propValue);
        docProperties[iArrIndex++] = docProperty;
    }
    metadata.setArrDocProperties(docProperties);
    return metadata;
}

Performance - Inefficient use of keySet iterator instead of entrySet iterator

1 Answers1