Java Array to Delimited String arrayToCommaDelimitedString(Object[] arr)

Description

Convenience method to return a String array as a CSV String.

License

Apache License

Parameter

Parameter	Description
arr	the array to display

Return

the delimited String

Declaration

public static String arrayToCommaDelimitedString(Object[] arr) 

Method Source Code

//package com.java2s;
/*//from   ww w  . j a  v  a 2 s.  c o  m
 * Copyright 2002-2011 the original author or authors.
 *
 * Licensed 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.
 */

public class Main {
    private static final String EMPTY_STRING = "";
    private static final String NULL_STRING = "null";

    /**
     * Convenience method to return a String array as a CSV String.
     * E.g. useful for <code>toString()</code> implementations.
     * @param arr the array to display
     * @return the delimited String
     */
    public static String arrayToCommaDelimitedString(Object[] arr) {
        return arrayToDelimitedString(arr, ",");
    }

    /**
     * Convenience method to return a String array as a delimited (e.g. CSV)
     * String. E.g. useful for <code>toString()</code> implementations.
     * @param arr the array to display
     * @param delim the delimiter to use (probably a ",")
     * @return the delimited String
     */
    public static String arrayToDelimitedString(Object[] arr, String delim) {
        if (isObjectEmpty(arr)) {
            return "";
        }
        if (arr.length == 1) {
            return nullSafeToString(arr[0]);
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < arr.length; i++) {
            if (i > 0) {
                sb.append(delim);
            }
            sb.append(arr[i]);
        }
        return sb.toString();
    }

    /**
     * Determine whether the given array is empty:
     * i.e. <code>null</code> or of zero length.
     * @param array the array to check
     */
    public static boolean isObjectEmpty(Object[] array) {
        return (array == null || array.length == 0);
    }

    /**
     * Return a String representation of the specified Object.
     * <p>Builds a String representation of the contents in case of an array.
     * Returns <code>"null"</code> if <code>obj</code> is <code>null</code>.
     * @param obj the object to build a String representation for
     * @return a String representation of <code>obj</code>
     */
    public static String nullSafeToString(Object obj) {
        if (obj == null) {
            return NULL_STRING;
        }
        if (obj instanceof String) {
            return (String) obj;
        }
        if (obj instanceof Object[]) {
            return nullSafeToString((Object[]) obj);
        }
        if (obj instanceof boolean[]) {
            return nullSafeToString((boolean[]) obj);
        }
        if (obj instanceof byte[]) {
            return nullSafeToString((byte[]) obj);
        }
        if (obj instanceof char[]) {
            return nullSafeToString((char[]) obj);
        }
        if (obj instanceof double[]) {
            return nullSafeToString((double[]) obj);
        }
        if (obj instanceof float[]) {
            return nullSafeToString((float[]) obj);
        }
        if (obj instanceof int[]) {
            return nullSafeToString((int[]) obj);
        }
        if (obj instanceof long[]) {
            return nullSafeToString((long[]) obj);
        }
        if (obj instanceof short[]) {
            return nullSafeToString((short[]) obj);
        }
        String str = obj.toString();
        return (str != null ? str : EMPTY_STRING);
    }
}

Related

1. arrayAsCommaSeperatedList(String... items)
2. arrayAsString(final int[] _intArray)
3. arrayToCommaDelimitedString(Object[] arr)
4. arrayToCommaDelimitedString(Object[] strings)
5. arrayToCommaSeparatedString(int[] array)
6. arrayToCommaString(int[] array)