Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

import java.util.Collection;
import java.util.Iterator;

public class Main {
    /**
     * <p>
     * Joins the elements of the provided array into a single String containing
     * the provided list of elements.
     * </p>
     * <p>
     * No separator is added to the joined String. Null objects or empty strings
     * within the array are represented by empty strings.
     * </p>
     * 
     * <pre>
     * StringUtils.join(null)            = null
     * StringUtils.join([])              = ""
     * StringUtils.join([null])          = ""
     * StringUtils.join(["a", "b", "c"]) = "abc"
     * StringUtils.join([null, "", "a"]) = "a"
     * </pre>
     * 
     * @param array the array of values to join together, may be null
     * @return the joined String, <code>null</code> if null array input
     * @since 2.0
     */
    public static String join(Object[] array) {
        return join(array, null);
    }

    /**
     * <p>
     * Joins the elements of the provided array into a single String containing
     * the provided list of elements.
     * </p>
     * <p>
     * No delimiter is added before or after the list. Null objects or empty
     * strings within the array are represented by empty strings.
     * </p>
     * 
     * <pre>
     * StringUtils.join(null, *)               = null
     * StringUtils.join([], *)                 = ""
     * StringUtils.join([null], *)             = ""
     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
     * StringUtils.join(["a", "b", "c"], null) = "abc"
     * StringUtils.join([null, "", "a"], ';')  = ";;a"
     * </pre>
     * 
     * @param array the array of values to join together, may be null
     * @param separator the separator character to use
     * @return the joined String, <code>null</code> if null array input
     * @since 2.0
     */
    public static String join(Object[] array, char separator) {
        if (array == null) {
            return null;
        }

        return join(array, separator, 0, array.length);
    }

    /**
     * <p>
     * Joins the elements of the provided array into a single String containing
     * the provided list of elements.
     * </p>
     * <p>
     * No delimiter is added before or after the list. Null objects or empty
     * strings within the array are represented by empty strings.
     * </p>
     * 
     * <pre>
     * StringUtils.join(null, *)               = null
     * StringUtils.join([], *)                 = ""
     * StringUtils.join([null], *)             = ""
     * StringUtils.join(["a", "b", "c"], ';')  = "a;b;c"
     * StringUtils.join(["a", "b", "c"], null) = "abc"
     * StringUtils.join([null, "", "a"], ';')  = ";;a"
     * </pre>
     * 
     * @param array the array of values to join together, may be null
     * @param separator the separator character to use
     * @param startIndex the first index to start joining from. It is an error
     *            to pass in an end index past the end of the array
     * @param endIndex the index to stop joining from (exclusive). It is an
     *            error to pass in an end index past the end of the array
     * @return the joined String, <code>null</code> if null array input
     * @since 2.0
     */
    public static String join(Object[] array, char separator, int startIndex, int endIndex) {
        if (array == null) {
            return null;
        }
        int bufSize = (endIndex - startIndex);
        if (bufSize <= 0) {
            return "";
        }

        bufSize *= ((array[startIndex] == null ? 16 : array[startIndex].toString().length()) + 1);
        StringBuffer buf = new StringBuffer(bufSize);

        for (int i = startIndex; i < endIndex; i++) {
            if (i > startIndex) {
                buf.append(separator);
            }
            if (array[i] != null) {
                buf.append(array[i]);
            }
        }
        return buf.toString();
    }

    /**
     * <p>
     * Joins the elements of the provided array into a single String containing
     * the provided list of elements.
     * </p>
     * <p>
     * No delimiter is added before or after the list. A <code>null</code>
     * separator is the same as an empty String (""). Null objects or empty
     * strings within the array are represented by empty strings.
     * </p>
     * 
     * <pre>
     * StringUtils.join(null, *)                = null
     * StringUtils.join([], *)                  = ""
     * StringUtils.join([null], *)              = ""
     * StringUtils.join(["a", "b", "c"], "--")  = "a--b--c"
     * StringUtils.join(["a", "b", "c"], null)  = "abc"
     * StringUtils.join(["a", "b", "c"], "")    = "abc"
     * StringUtils.join([null, "", "a"], ',')   = ",,a"
     * </pre>
     * 
     * @param array the array of values to join together, may be null
     * @param separator the separator character to use, null treated as ""
     * @return the joined String, <code>null</code> if null array input
     */
    public static String join(Object[] array, String separator) {
        if (array == null) {
            return null;
        }
        return join(array, separator, 0, array.length);
    }

    /**
     * <p>
     * Joins the elements of the provided array into a single String containing
     * the provided list of elements.
     * </p>
     * <p>
     * No delimiter is added before or after the list. A <code>null</code>
     * separator is the same as an empty String (""). Null objects or empty
     * strings within the array are represented by empty strings.
     * </p>
     * 
     * <pre>
     * StringUtils.join(null, *)                = null
     * StringUtils.join([], *)                  = ""
     * StringUtils.join([null], *)              = ""
     * StringUtils.join(["a", "b", "c"], "--")  = "a--b--c"
     * StringUtils.join(["a", "b", "c"], null)  = "abc"
     * StringUtils.join(["a", "b", "c"], "")    = "abc"
     * StringUtils.join([null, "", "a"], ',')   = ",,a"
     * </pre>
     * 
     * @param array the array of values to join together, may be null
     * @param separator the separator character to use, null treated as ""
     * @param startIndex the first index to start joining from. It is an error
     *            to pass in an end index past the end of the array
     * @param endIndex the index to stop joining from (exclusive). It is an
     *            error to pass in an end index past the end of the array
     * @return the joined String, <code>null</code> if null array input
     */
    public static String join(Object[] array, String separator, int startIndex, int endIndex) {
        if (array == null) {
            return null;
        }
        if (separator == null) {
            separator = "";
        }

        // endIndex - startIndex > 0: Len = NofStrings *(len(firstString) +
        // len(separator))
        // (Assuming that all Strings are roughly equally long)
        int bufSize = (endIndex - startIndex);
        if (bufSize <= 0) {
            return "";
        }

        bufSize *= ((array[startIndex] == null ? 16 : array[startIndex].toString().length()) + separator.length());

        StringBuffer buf = new StringBuffer(bufSize);

        for (int i = startIndex; i < endIndex; i++) {
            if (i > startIndex) {
                buf.append(separator);
            }
            if (array[i] != null) {
                buf.append(array[i]);
            }
        }
        return buf.toString();
    }

    /**
     * <p>
     * Joins the elements of the provided <code>Iterator</code> into a single
     * String containing the provided elements.
     * </p>
     * <p>
     * No delimiter is added before or after the list. Null objects or empty
     * strings within the iteration are represented by empty strings.
     * </p>
     * <p>
     * See the examples here: {@link #join(Object[],char)}.
     * </p>
     * 
     * @param iterator the <code>Iterator</code> of values to join together, may
     *            be null
     * @param separator the separator character to use
     * @return the joined String, <code>null</code> if null iterator input
     * @since 2.0
     */
    public static String join(Iterator<?> iterator, char separator) {

        // handle null, zero and one elements before building a buffer
        if (iterator == null) {
            return null;
        }
        if (!iterator.hasNext()) {
            return "";
        }
        Object first = iterator.next();
        if (!iterator.hasNext()) {
            return first.toString();
        }

        // two or more elements
        StringBuffer buf = new StringBuffer(256); // Java default is 16,
                                                  // probably too small
        if (first != null) {
            buf.append(first);
        }

        while (iterator.hasNext()) {
            buf.append(separator);
            Object obj = iterator.next();
            if (obj != null) {
                buf.append(obj);
            }
        }

        return buf.toString();
    }

    /**
     * <p>
     * Joins the elements of the provided <code>Iterator</code> into a single
     * String containing the provided elements.
     * </p>
     * <p>
     * No delimiter is added before or after the list. A <code>null</code>
     * separator is the same as an empty String ("").
     * </p>
     * <p>
     * See the examples here: {@link #join(Object[],String)}.
     * </p>
     * 
     * @param iterator the <code>Iterator</code> of values to join together, may
     *            be null
     * @param separator the separator character to use, null treated as ""
     * @return the joined String, <code>null</code> if null iterator input
     */
    public static String join(Iterator<?> iterator, String separator) {

        // handle null, zero and one elements before building a buffer
        if (iterator == null) {
            return null;
        }
        if (!iterator.hasNext()) {
            return "";
        }
        Object first = iterator.next();
        if (!iterator.hasNext()) {
            return first.toString();
        }

        // two or more elements
        StringBuffer buf = new StringBuffer(256); // Java default is 16,
                                                  // probably too small
        if (first != null) {
            buf.append(first);
        }

        while (iterator.hasNext()) {
            if (separator != null) {
                buf.append(separator);
            }
            Object obj = iterator.next();
            if (obj != null) {
                buf.append(obj);
            }
        }
        return buf.toString();
    }

    /**
     * <p>
     * Joins the elements of the provided <code>Collection</code> into a single
     * String containing the provided elements.
     * </p>
     * <p>
     * No delimiter is added before or after the list. Null objects or empty
     * strings within the iteration are represented by empty strings.
     * </p>
     * <p>
     * See the examples here: {@link #join(Object[],char)}.
     * </p>
     * 
     * @param collection the <code>Collection</code> of values to join together,
     *            may be null
     * @param separator the separator character to use
     * @return the joined String, <code>null</code> if null iterator input
     * @since 2.3
     */
    public static String join(Collection<?> collection, char separator) {
        if (collection == null) {
            return null;
        }
        return join(collection.iterator(), separator);
    }

    /**
     * <p>
     * Joins the elements of the provided <code>Collection</code> into a single
     * String containing the provided elements.
     * </p>
     * <p>
     * No delimiter is added before or after the list. A <code>null</code>
     * separator is the same as an empty String ("").
     * </p>
     * <p>
     * See the examples here: {@link #join(Object[],String)}.
     * </p>
     * 
     * @param collection the <code>Collection</code> of values to join together,
     *            may be null
     * @param separator the separator character to use, null treated as ""
     * @return the joined String, <code>null</code> if null iterator input
     * @since 2.3
     */
    public static String join(Collection<?> collection, String separator) {
        if (collection == null) {
            return null;
        }
        return join(collection.iterator(), separator);
    }
}