Find the latest index of any of a set of potential substrings. A null String will return -1. - Java java.lang

Description

Find the latest index of any of a set of potential substrings. A null String will return -1.

Demo Code

/*/* www. j a va2 s  .c o m*/
 * Copyright 2013 Guidewire Software, Inc.
 */
/**
 * This class is based, in part, on org.apache.commons.lang.StringUtils and is intended
 * to break the dependency on that project.
 *
 * @author <a href="http://jakarta.apache.org/turbine/">Apache Jakarta Turbine</a>
 * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
 * @author Daniel L. Rall
 * @author <a href="mailto:gcoladonato@yahoo.com">Greg Coladonato</a>
 * @author <a href="mailto:ed@apache.org">Ed Korthof</a>
 * @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>
 * @author Stephen Colebourne
 * @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>
 * @author Holger Krauth
 * @author <a href="mailto:alex@purpletech.com">Alexander Day Chaffee</a>
 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
 * @author Arun Mammen Thomas
 * @author Gary Gregory
 * @author Phil Steitz
 * @author Al Chou
 * @author Michael Davey
 * @author Reuben Sivan
 * @author Chris Hyzer
 *  Johnson

 */
//package com.java2s;

public class Main {
    public static void main(String[] argv) {
        String str = "java2s.com";
        String[] searchStrs = new String[] { "1", "abc", "level", null,
                "java2s.com", "asdf 123" };
        System.out.println(lastIndexOfAny(str, searchStrs));
    }

    /**
     * <p>Find the latest index of any of a set of potential substrings.</p>
     *
     * <p>A <code>null</code> String will return <code>-1</code>.
     * A <code>null</code> search array will return <code>-1</code>.
     * A <code>null</code> or zero length search array entry will be ignored,
     * but a search array containing "" will return the length of <code>str</code>
     * if <code>str</code> is not null. This method uses {@link String#indexOf(String)}</p>
     *
     * <pre>
     * lastIndexOfAny(null, *)                   = -1
     * lastIndexOfAny(*, null)                   = -1
     * lastIndexOfAny(*, [])                     = -1
     * lastIndexOfAny(*, [null])                 = -1
     * lastIndexOfAny("zzabyycdxx", ["ab","cd"]) = 6
     * lastIndexOfAny("zzabyycdxx", ["cd","ab"]) = 6
     * lastIndexOfAny("zzabyycdxx", ["mn","op"]) = -1
     * lastIndexOfAny("zzabyycdxx", ["mn","op"]) = -1
     * lastIndexOfAny("zzabyycdxx", ["mn",""])   = 10
     * </pre>
     *
     * @param str  the String to check, may be null
     * @param searchStrs  the Strings to search for, may be null
     * @return the last index of any of the Strings, -1 if no match
     */
    public static int lastIndexOfAny(String str, String[] searchStrs) {
        if ((str == null) || (searchStrs == null)) {
            return -1;
        }
        int sz = searchStrs.length;
        int ret = -1;
        int tmp = 0;
        for (int i = 0; i < sz; i++) {
            String search = searchStrs[i];
            if (search == null) {
                continue;
            }
            tmp = str.lastIndexOf(search);
            if (tmp > ret) {
                ret = tmp;
            }
        }
        return ret;
    }

    /**
     * <p>Finds the last index within a String, handling <code>null</code>.
     * This method uses {@link String#lastIndexOf(int)}.</p>
     *
     * <p>A <code>null</code> or empty ("") String will return <code>-1</code>.</p>
     *
     * <pre>
     * lastIndexOf(null, *)         = -1
     * lastIndexOf("", *)           = -1
     * lastIndexOf("aabaabaa", 'a') = 7
     * lastIndexOf("aabaabaa", 'b') = 5
     * </pre>
     *
     * @param str  the String to check, may be null
     * @param searchChar  the character to find
     * @return the last index of the search character,
     *  -1 if no match or <code>null</code> string input
     * @since 2.0
     */
    public static int lastIndexOf(String str, char searchChar) {
        if (isEmpty(str)) {
            return -1;
        }
        return str.lastIndexOf(searchChar);
    }

    /**
     * <p>Finds the last index within a String from a start position,
     * handling <code>null</code>.
     * This method uses {@link String#lastIndexOf(int, int)}.</p>
     *
     * <p>A <code>null</code> or empty ("") String will return <code>-1</code>.
     * A negative start position returns <code>-1</code>.
     * A start position greater than the string length searches the whole string.</p>
     *
     * <pre>
     * lastIndexOf(null, *, *)          = -1
     * lastIndexOf("", *,  *)           = -1
     * lastIndexOf("aabaabaa", 'b', 8)  = 5
     * lastIndexOf("aabaabaa", 'b', 4)  = 2
     * lastIndexOf("aabaabaa", 'b', 0)  = -1
     * lastIndexOf("aabaabaa", 'b', 9)  = 5
     * lastIndexOf("aabaabaa", 'b', -1) = -1
     * lastIndexOf("aabaabaa", 'a', 0)  = 0
     * </pre>
     *
     * @param str  the String to check, may be null
     * @param searchChar  the character to find
     * @param startPos  the start position
     * @return the last index of the search character,
     *  -1 if no match or <code>null</code> string input
     * @since 2.0
     */
    public static int lastIndexOf(String str, char searchChar, int startPos) {
        if (isEmpty(str)) {
            return -1;
        }
        return str.lastIndexOf(searchChar, startPos);
    }

    /**
     * <p>Finds the last index within a String, handling <code>null</code>.
     * This method uses {@link String#lastIndexOf(String)}.</p>
     *
     * <p>A <code>null</code> String will return <code>-1</code>.</p>
     *
     * <pre>
     * lastIndexOf(null, *)          = -1
     * lastIndexOf(*, null)          = -1
     * lastIndexOf("", "")           = 0
     * lastIndexOf("aabaabaa", "a")  = 0
     * lastIndexOf("aabaabaa", "b")  = 2
     * lastIndexOf("aabaabaa", "ab") = 1
     * lastIndexOf("aabaabaa", "")   = 8
     * </pre>
     *
     * @param str  the String to check, may be null
     * @param searchStr  the String to find, may be null
     * @return the last index of the search String,
     *  -1 if no match or <code>null</code> string input
     * @since 2.0
     */
    public static int lastIndexOf(String str, String searchStr) {
        if (str == null || searchStr == null) {
            return -1;
        }
        return str.lastIndexOf(searchStr);
    }

    /**
     * <p>Finds the first index within a String, handling <code>null</code>.
     * This method uses {@link String#lastIndexOf(String, int)}.</p>
     *
     * <p>A <code>null</code> String will return <code>-1</code>.
     * A negative start position returns <code>-1</code>.
     * An empty ("") search String always matches unless the start position is negative.
     * A start position greater than the string length searches the whole string.</p>
     *
     * <pre>
     * lastIndexOf(null, *, *)          = -1
     * lastIndexOf(*, null, *)          = -1
     * lastIndexOf("aabaabaa", "a", 8)  = 7
     * lastIndexOf("aabaabaa", "b", 8)  = 5
     * lastIndexOf("aabaabaa", "ab", 8) = 4
     * lastIndexOf("aabaabaa", "b", 9)  = 5
     * lastIndexOf("aabaabaa", "b", -1) = -1
     * lastIndexOf("aabaabaa", "a", 0)  = 0
     * lastIndexOf("aabaabaa", "b", 0)  = -1
     * </pre>
     *
     * @param str  the String to check, may be null
     * @param searchStr  the String to find, may be null
     * @param startPos  the start position, negative treated as zero
     * @return the first index of the search String,
     *  -1 if no match or <code>null</code> string input
     * @since 2.0
     */
    public static int lastIndexOf(String str, String searchStr, int startPos) {
        if (str == null || searchStr == null) {
            return -1;
        }
        return str.lastIndexOf(searchStr, startPos);
    }

    /**
     * <p>Checks if a String is empty ("") or null.</p>
     *
     * <pre>
     * StringUtils.isEmpty(null)      = true
     * StringUtils.isEmpty("")        = true
     * StringUtils.isEmpty(" ")       = false
     * StringUtils.isEmpty("bob")     = false
     * StringUtils.isEmpty("  bob  ") = false
     * </pre>
     *
     * <p>NOTE: This method changed in Lang version 2.0.
     * It no longer trims the String.
     * That functionality is available in isBlank().</p>
     *
     * @param str  the String to check, may be null
     * @return <code>true</code> if the String is empty or null
     */
    public static boolean isEmpty(String str) {
        return str == null || str.length() == 0;
    }
}

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