Tenfold improvement in performance for leftPad, rightPad and repeat when repeat is over a String of length 1, by implementation of a padding method. The padding method is kept private for the moment.
Also a modification of containsOnly so it has a partner method indexOfAnyBut. Unit Test added for indexOfAnyBut. Submitted by: Robert Simpson git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/lang/trunk@137299 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Henri Yandell
parent
92a9a68b72
commit
eb6a2942c0
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@ -76,10 +76,30 @@ import java.util.StringTokenizer;
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* @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
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* @author Arun Mammen Thomas
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* @since 1.0
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* @version $Id: StringUtils.java,v 1.43 2003/04/10 00:01:21 ggregory Exp $
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* @version $Id: StringUtils.java,v 1.44 2003/04/16 04:37:33 bayard Exp $
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*/
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public class StringUtils {
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/**
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* <p>The maximum size to which the padding constant(s) can expand.</p>
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*/
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private static int PAD_LIMIT = 8192;
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/**
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* <p>A <code>String</code> containing all blank characters.</p>
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*
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* <p>Used for efficient blank padding. The length of the string expands as needed.</p>
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*/
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private static String blanks = new String(" ");
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/**
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* <p>An array of <code>String</code>s used for padding.</p>
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*
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* <p>Used for efficient blank padding. The length of each string expands as needed.</p>
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*/
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private final static String[] padding = new String[Character.MAX_VALUE];
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// String.concat about twice as fast as StringBuffer.append
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/**
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* <p><code>StringUtils<code> instances should NOT be constructed in
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* standard programming. Instead, the class should be used as
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@ -1178,6 +1198,10 @@ public class StringUtils {
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* @throws NullPointerException if str is <code>null</code>
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*/
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public static String repeat(String str, int repeat) {
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if (str.length() == 1 && repeat <= PAD_LIMIT) {
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return padding(repeat, str.charAt(0));
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}
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StringBuffer buffer = new StringBuffer(repeat * str.length());
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for (int i = 0; i < repeat; i++) {
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buffer.append(str);
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@ -1185,20 +1209,84 @@ public class StringUtils {
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return buffer.toString();
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}
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/**
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* <p>Returns blank padding with a given length.</p>
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*
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* @param repeat number of times to repeat a blank
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* @return String with repeated character
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* @throws IndexOutOfBoundsException if repeat < 0
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*/
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private static String padding(int repeat) {
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while (blanks.length() < repeat) {
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blanks = blanks.concat(blanks);
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}
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return blanks.substring(0, repeat);
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}
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/**
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* <p>Returns padding using the specified delimiter repeated to a given length.
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* </p>
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*
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* @param repeat number of times to repeat delim
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* @param delim character to repeat
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* @return String with repeated character
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* @throws NullPointerException if delim is <code>null</code>
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* @throws IndexOutOfBoundsException if repeat < 0
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*/
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private static String padding(int repeat, char delim) {
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if (padding[delim] == null) {
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padding[delim] = String.valueOf(delim);
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}
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while (padding[delim].length() < repeat) {
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padding[delim] = padding[delim].concat(padding[delim]);
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}
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return padding[delim].substring(0, repeat);
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}
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/**
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* <p>Right pad a String with spaces.</p>
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*
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* <p>The String is padded to the size of <code>n</code>.</p>
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*
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* @param str String to repeat
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* @param str String to pad out
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* @param size number of times to repeat str
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* @return right padded String
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* @return right padded String or original String if no padding is necessary
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* @throws NullPointerException if str is <code>null</code>
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*/
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public static String rightPad(String str, int size) {
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return rightPad(str, size, " ");
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int pads = size - str.length();
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if (pads <= 0) {
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return str; // returns original string when possible
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}
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if (pads > PAD_LIMIT) {
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return rightPad(str, size, " ");
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}
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return str + padding(pads);
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}
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/**
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* <p>Right pad a String with a specified character.</p>
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*
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* <p>The String is padded to the size of <code>n</code>.</p>
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*
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* @param str String to pad out
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* @param size size to pad to
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* @param delim character to pad with
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* @return right padded String or original String if no padding is necessary
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* @throws NullPointerException if str or delim is <code>null<code>
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*/
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public static String rightPad(String str, int size, char delim) {
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int pads = size - str.length();
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if (pads <= 0) {
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return str; // returns original string when possible
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}
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if (pads > PAD_LIMIT) {
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return rightPad(str, size, String.valueOf(delim));
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}
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return str + padding(pads, delim);
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}
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/**
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* <p>Right pad a String with a specified string.</p>
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*
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@ -1207,11 +1295,15 @@ public class StringUtils {
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* @param str String to pad out
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* @param size size to pad to
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* @param delim String to pad with
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* @return right padded String
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* @return right padded String or original String if no padding is necessary
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* @throws NullPointerException if str or delim is <code>null<code>
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* @throws ArithmeticException if delim is the empty String
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*/
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public static String rightPad(String str, int size, String delim) {
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if (delim.length() == 1 && size - str.length() <= PAD_LIMIT) {
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return rightPad(str, size, delim.charAt(0));
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}
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size = (size - str.length()) / delim.length();
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if (size > 0) {
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str += repeat(delim, size);
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@ -1226,23 +1318,53 @@ public class StringUtils {
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*
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* @param str String to pad out
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* @param size size to pad to
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* @return left padded String
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* @return left padded String or original String if no padding is necessary
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* @throws NullPointerException if str or delim is <code>null<code>
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*/
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public static String leftPad(String str, int size) {
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return leftPad(str, size, " ");
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int pads = size - str.length();
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if (pads <= 0) {
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return str; // returns original string when possible
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}
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if (pads > PAD_LIMIT) {
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return leftPad(str, size, " ");
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}
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return padding(pads).concat(str);
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}
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/**
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* Left pad a String with a specified character. Pad to a size of n.
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*
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* @param str String to pad out
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* @param size size to pad to
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* @param delim character to pad with
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* @return left padded String or original String if no padding is necessary
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* @throws NullPointerException if str or delim is <code>null</code>
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*/
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public static String leftPad(String str, int size, char delim) {
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int pads = size - str.length();
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if (pads <= 0) {
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return str; // returns original string when possible
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}
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if (pads > PAD_LIMIT) {
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return leftPad(str, size, " ");
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}
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return padding(pads, delim).concat(str);
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}
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/**
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* Left pad a String with a specified string. Pad to a size of n.
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*
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* @param str String to pad out
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* @param size size to pad to
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* @param delim String to pad with
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* @return left padded String
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* @return left padded String or original String if no padding is necessary
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* @throws NullPointerException if str or delim is null
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* @throws ArithmeticException if delim is the empty string
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*/
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public static String leftPad(String str, int size, String delim) {
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if (delim.length() == 1 && size - str.length() <= PAD_LIMIT)
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return leftPad(str, size, delim.charAt(0));
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size = (size - str.length()) / delim.length();
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if (size > 0) {
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str = repeat(delim, size) + str;
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@ -1813,6 +1935,7 @@ public class StringUtils {
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* @param validChars an array of valid chars
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* @return true if it only contains valid chars and is non-null
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*/
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/* rewritten
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public static boolean containsOnly(String str, char[] validChars) {
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if (str == null || validChars == null) {
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return false;
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@ -1834,6 +1957,7 @@ public class StringUtils {
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}
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return true;
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}
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*/
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/**
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* <p>Checks that the String does not contain certain chars.</p>
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@ -1873,6 +1997,66 @@ public class StringUtils {
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return true;
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}
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/**
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* <p>Checks if the String contains only certain chars.</p>
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*
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* @param str the String to check
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* @param valid an array of valid chars
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* @return true if it only contains valid chars and is non-null
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*/
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public static boolean containsOnly(String str, char[] valid) {
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// All these pre-checks are to maintain API with an older version
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if( (valid == null) || (str == null) ) {
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return false;
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}
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if(str.length() == 0) {
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return true;
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}
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if(valid.length == 0) {
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return false;
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}
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return indexOfAnyBut(str, valid) == -1;
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}
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/**
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* <p>Search a String to find the first index of any
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* character not in the given set of characters.</p>
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*
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* @param str the String to check
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* @param searchChars the chars to search for
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* @return the index of any of the chars
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* @throws NullPointerException if either str or searchChars is <code>null</code>
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*/
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public static int indexOfAnyBut(String str, char[] searchChars) {
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if(searchChars == null) {
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return -1;
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}
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return indexOfAnyBut(str, new String(searchChars));
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}
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/**
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* <p>Search a String to find the first index of any
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* character not in the given set of characters.</p>
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*
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* @param str the String to check
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* @param searchChars a String containing the chars to search for
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* @return the last index of any of the chars
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* @throws NullPointerException if either str or searchChars is <code>null</code>
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*/
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public static int indexOfAnyBut(String str, String searchChars) {
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if (str == null || searchChars == null) {
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return -1;
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}
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for (int i = 0; i < str.length(); i ++) {
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if (searchChars.indexOf(str.charAt(i)) < 0) {
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return i;
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}
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}
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return -1;
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}
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// Defaults
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//--------------------------------------------------------------------------
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@ -1955,7 +2139,7 @@ public class StringUtils {
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* In no case will it return a string of length greater than maxWidth.
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*
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* @param maxWidth maximum length of result string
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**/
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*/
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public static String abbreviate(String s, int maxWidth) {
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return abbreviate(s, 0, maxWidth);
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}
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@ -1971,7 +2155,7 @@ public class StringUtils {
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*
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* @param offset left edge of source string
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* @param maxWidth maximum length of result string
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**/
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*/
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public static String abbreviate(String s, int offset, int maxWidth) {
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if (maxWidth < 4)
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throw new IllegalArgumentException("Minimum abbreviation width is 4");
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@ -2103,3 +2287,4 @@ public class StringUtils {
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}
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}
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@ -69,7 +69,7 @@ import junit.textui.TestRunner;
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* @author <a href="mailto:fredrik@westermarck.com>Fredrik Westermarck</a>
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* @author Holger Krauth
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* @author <a href="hps@intermeta.de">Henning P. Schmiedehausen</a>
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* @version $Id: StringUtilsTest.java,v 1.18 2003/04/09 18:45:29 alex Exp $
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* @version $Id: StringUtilsTest.java,v 1.19 2003/04/16 04:37:33 bayard Exp $
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*/
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public class StringUtilsTest extends TestCase {
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@ -564,6 +564,31 @@ public class StringUtilsTest extends TestCase {
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assertEquals("containsNone(str3, chars3)", true, StringUtils.containsNone(str3, chars3));
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}
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public void testIndexOfAnyBut() {
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String str1 = "a";
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String str2 = "b";
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String str3 = "ab";
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String chars1= "b";
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String chars2= "a";
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String chars3= "ab";
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String emptyChars = "";
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assertEquals("indexOfAnyBut(null, null)", -1, StringUtils.indexOfAnyBut(null, (String) null));
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assertEquals("indexOfAnyBut(empty-string, null)", -1, StringUtils.indexOfAnyBut("", (String) null));
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assertEquals("indexOfAnyBut(null, empty-string)", -1, StringUtils.indexOfAnyBut(null, emptyChars));
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assertEquals("indexOfAnyBut(str1, empty-char-array)", 0, StringUtils.indexOfAnyBut(str1, emptyChars));
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assertEquals("indexOfAnyBut(empty-string, empty-char-array)", -1, StringUtils.indexOfAnyBut("", emptyChars));
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assertEquals("indexOfAnyBut(empty-string, chars1)", -1, StringUtils.indexOfAnyBut("", chars1));
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assertEquals("indexOfAnyBut(str1, chars1)", 0, StringUtils.indexOfAnyBut(str1, chars1));
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assertEquals("indexOfAnyBut(str1, chars2)", -1, StringUtils.indexOfAnyBut(str1, chars2));
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assertEquals("indexOfAnyBut(str1, chars3)", -1, StringUtils.indexOfAnyBut(str1, chars3));
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assertEquals("indexOfAnyBut(str2, chars1)", -1, StringUtils.indexOfAnyBut(str2, chars1));
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assertEquals("indexOfAnyBut(str2, chars2)", 0, StringUtils.indexOfAnyBut(str2, chars2));
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assertEquals("indexOfAnyBut(str2, chars3)", -1, StringUtils.indexOfAnyBut(str2, chars3));
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assertEquals("indexOfAnyBut(String3, chars1)", 0, StringUtils.indexOfAnyBut(str3, chars1));
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assertEquals("indexOfAnyBut(String3, chars2)", 1, StringUtils.indexOfAnyBut(str3, chars2));
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assertEquals("indexOfAnyBut(String3, chars3)", -1, StringUtils.indexOfAnyBut(str3, chars3));
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}
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public void testAbbreviate()
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{
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assertEquals("abbreviate(String,int) failed",
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