JoinUtil.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.karaf.tools.utils;

/**
 * Join strings with commas. This has some reflection to be usable with
 * the pax-exam
 */
public class JoinUtil {

    private JoinUtil() {
    }
    
    public static String join(String... options) {
        return join((Object[])options);
    }

    public static String join(Object[] options) {
        StringBuilder buffer = new StringBuilder();
        for (Object option : options) {
            String value = getStringValue(option);
            if (buffer.length() > 0 && !value.startsWith(",")) {
                buffer.append(",");
            }
            buffer.append(value);
        }
        return buffer.toString();
    }

    @SuppressWarnings("unchecked")
    private static String getStringValue(Object option) {
        if (option == null) {
            return "";
        }
        else if (option instanceof String) {
            return (String)option;
        }
        else if (option instanceof JoinableValue) {
            return ((JoinableValue<String>)option).getValue();
        }
        else {
            return "";
        }
    }
}