KvpNormalizer.java

package org.deegree.securityproxy.request;

import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.commons.lang.ArrayUtils;

/**
 * Key-Value-Pair normalizer
 * 
 * @author <a href="mailto:erben@lat-lon.de">Alexander Erben</a>
 * @author last edited by: $Author: lyn $
 * 
 * @version $Revision: $, $Date: $
 */
public final class KvpNormalizer {

    private KvpNormalizer() {
    }
    
    /**
     * @param parameterMap
     *            a map of parameters, never <code>null</code>
     * @return the incoming map with keys in lower cases, duplicated keys are merged into one key with multiple values;
     *         never <code>null</code>
     */
    public static Map<String, String[]> normalizeKvpMap( Map<String, String[]> parameterMap ) {
        Map<String, String[]> normalizedMap = new HashMap<String, String[]>();
        for ( Entry<String, String[]> entry : parameterMap.entrySet() ) {
            String key = entry.getKey().toLowerCase();
            String[] value = entry.getValue();
            if ( !normalizedMap.containsKey( key ) ) {
                normalizedMap.put( key, value );
            } else {
                String[] newValue = (String[]) ArrayUtils.addAll( value, normalizedMap.get( key ) );
                normalizedMap.put( key, newValue );
            }
        }
        return normalizedMap;
    }

}