org.openstack4j.openstack.storage.object.functions.MetadataToHeadersFunction Maven / Gradle / Ivy

package org.openstack4j.openstack.storage.object.functions;

import java.util.Map;

import com.google.common.base.Function;
import com.google.common.collect.Maps;

/**
 * Transforms a MetaHeaderRequestWrapper which applies headers based on a prefix to the outbound
 * HttpRequest
 * 
 * @author Jeremy Unruh
 */
public class MetadataToHeadersFunction implements Function, Map> {

    private String prefix;
    
    private MetadataToHeadersFunction(String prefix) {
        this.prefix = prefix;
    }
    
    /**
     * Creates a new Metadata to Headers function
     * 
     * @param prefix the prefix used for headers
     * @return MetadataToHeadersFunction
     */
    public static  MetadataToHeadersFunction create(String prefix) {
        return new MetadataToHeadersFunction(prefix);
    }
    
    /**
     * Transforms metadata raw values into header form values
     * 
     * @param metadata the map of metadata 
     * @return map of metadata in header format
     */
    @Override
    public Map apply(Map metadata) {
        
        Map headers = Maps.newHashMap();
        
        for (String key : metadata.keySet()) {
            String keyLower = key.toLowerCase();
            String value = metadata.get(key);
            if (keyLower.startsWith(prefix.toLowerCase()))
                headers.put(keyLower, value);
            else
                headers.put(String.format("%s%s", prefix, keyLower), value);
        }
        return headers;
    }

}