Example usage for java.lang CharSequence charAt

List of usage examples for java.lang CharSequence charAt

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Introduction

In this page you can find the example usage for java.lang CharSequence charAt.

Prototype

char charAt(int index);

Source Link

Document

Returns the char value at the specified index.

Usage

From source file:org.apache.commons.lang3.StringUtils.java

/**
 * <p>Checks if the CharSequence contains only Unicode letters.</p>
 *
 * <p>{@code null} will return {@code false}.
 * An empty CharSequence (length()=0) will return {@code false}.</p>
 *
 * <pre>//w w  w .  j  ava2 s . c om
 * StringUtils.isAlpha(null)   = false
 * StringUtils.isAlpha("")     = false
 * StringUtils.isAlpha("  ")   = false
 * StringUtils.isAlpha("abc")  = true
 * StringUtils.isAlpha("ab2c") = false
 * StringUtils.isAlpha("ab-c") = false
 * </pre>
 *
 * @param cs  the CharSequence to check, may be null
 * @return {@code true} if only contains letters, and is non-null
 * @since 3.0 Changed signature from isAlpha(String) to isAlpha(CharSequence)
 * @since 3.0 Changed "" to return false and not true
 */
public static boolean isAlpha(CharSequence cs) {
    if (cs == null || cs.length() == 0) {
        return false;
    }
    int sz = cs.length();
    for (int i = 0; i < sz; i++) {
        if (Character.isLetter(cs.charAt(i)) == false) {
            return false;
        }
    }
    return true;
}

From source file:org.apache.commons.lang3.StringUtils.java

/**
 * <p>Checks if the CharSequence contains only Unicode letters or digits.</p>
 *
 * <p>{@code null} will return {@code false}.
 * An empty CharSequence (length()=0) will return {@code false}.</p>
 *
 * <pre>//from  w ww. ja v  a 2  s  .c  o  m
 * StringUtils.isAlphanumeric(null)   = false
 * StringUtils.isAlphanumeric("")     = false
 * StringUtils.isAlphanumeric("  ")   = false
 * StringUtils.isAlphanumeric("abc")  = true
 * StringUtils.isAlphanumeric("ab c") = false
 * StringUtils.isAlphanumeric("ab2c") = true
 * StringUtils.isAlphanumeric("ab-c") = false
 * </pre>
 *
 * @param cs  the CharSequence to check, may be null
 * @return {@code true} if only contains letters or digits,
 *  and is non-null
 * @since 3.0 Changed signature from isAlphanumeric(String) to isAlphanumeric(CharSequence)
 * @since 3.0 Changed "" to return false and not true
 */
public static boolean isAlphanumeric(CharSequence cs) {
    if (cs == null || cs.length() == 0) {
        return false;
    }
    int sz = cs.length();
    for (int i = 0; i < sz; i++) {
        if (Character.isLetterOrDigit(cs.charAt(i)) == false) {
            return false;
        }
    }
    return true;
}

From source file:org.apache.commons.lang3.StringUtils.java

/**
 * <p>Search a CharSequence to find the first index of any
 * character not in the given set of characters.</p>
 *
 * <p>A {@code null} CharSequence will return {@code -1}.
 * A {@code null} or empty search string will return {@code -1}.</p>
 *
 * <pre>//from  w  w w . j a v a 2  s  .c o m
 * StringUtils.indexOfAnyBut(null, *)            = -1
 * StringUtils.indexOfAnyBut("", *)              = -1
 * StringUtils.indexOfAnyBut(*, null)            = -1
 * StringUtils.indexOfAnyBut(*, "")              = -1
 * StringUtils.indexOfAnyBut("zzabyycdxx", "za") = 3
 * StringUtils.indexOfAnyBut("zzabyycdxx", "")   = -1
 * StringUtils.indexOfAnyBut("aba","ab")         = -1
 * </pre>
 *
 * @param seq  the CharSequence to check, may be null
 * @param searchChars  the chars to search for, may be null
 * @return the index of any of the chars, -1 if no match or null input
 * @since 2.0
 * @since 3.0 Changed signature from indexOfAnyBut(String, String) to indexOfAnyBut(CharSequence, CharSequence)
 */
public static int indexOfAnyBut(CharSequence seq, CharSequence searchChars) {
    if (isEmpty(seq) || isEmpty(searchChars)) {
        return INDEX_NOT_FOUND;
    }
    int strLen = seq.length();
    for (int i = 0; i < strLen; i++) {
        char ch = seq.charAt(i);
        boolean chFound = CharSequenceUtils.indexOf(searchChars, ch, 0) >= 0;
        if (i + 1 < strLen && Character.isHighSurrogate(ch)) {
            char ch2 = seq.charAt(i + 1);
            if (chFound && CharSequenceUtils.indexOf(searchChars, ch2, 0) < 0) {
                return i;
            }
        } else {
            if (!chFound) {
                return i;
            }
        }
    }
    return INDEX_NOT_FOUND;
}

From source file:org.apache.commons.lang3.StringUtils.java

/**
 * <p>Compares two CharSequences, and returns the index at which the
 * CharSequences begin to differ.</p>
 *
 * <p>For example,/*from  w ww.  j  a v a  2  s. c  o  m*/
 * {@code indexOfDifference("i am a machine", "i am a robot") -> 7}</p>
 *
 * <pre>
 * StringUtils.indexOfDifference(null, null) = -1
 * StringUtils.indexOfDifference("", "") = -1
 * StringUtils.indexOfDifference("", "abc") = 0
 * StringUtils.indexOfDifference("abc", "") = 0
 * StringUtils.indexOfDifference("abc", "abc") = -1
 * StringUtils.indexOfDifference("ab", "abxyz") = 2
 * StringUtils.indexOfDifference("abcde", "abxyz") = 2
 * StringUtils.indexOfDifference("abcde", "xyz") = 0
 * </pre>
 *
 * @param cs1  the first CharSequence, may be null
 * @param cs2  the second CharSequence, may be null
 * @return the index where cs1 and cs2 begin to differ; -1 if they are equal
 * @since 2.0
 * @since 3.0 Changed signature from indexOfDifference(String, String) to
 * indexOfDifference(CharSequence, CharSequence)
 */
public static int indexOfDifference(CharSequence cs1, CharSequence cs2) {
    if (cs1 == cs2) {
        return INDEX_NOT_FOUND;
    }
    if (cs1 == null || cs2 == null) {
        return 0;
    }
    int i;
    for (i = 0; i < cs1.length() && i < cs2.length(); ++i) {
        if (cs1.charAt(i) != cs2.charAt(i)) {
            break;
        }
    }
    if (i < cs2.length() || i < cs1.length()) {
        return i;
    }
    return INDEX_NOT_FOUND;
}

From source file:org.apache.commons.lang3.StringUtils.java

/**
 * <p>Checks that the CharSequence does not contain certain characters.</p>
 *
 * <p>A {@code null} CharSequence will return {@code true}.
 * A {@code null} invalid character array will return {@code true}.
 * An empty CharSequence (length()=0) always returns true.</p>
 *
 * <pre>/*  w  w  w. ja va  2s . c o  m*/
 * StringUtils.containsNone(null, *)       = true
 * StringUtils.containsNone(*, null)       = true
 * StringUtils.containsNone("", *)         = true
 * StringUtils.containsNone("ab", '')      = true
 * StringUtils.containsNone("abab", 'xyz') = true
 * StringUtils.containsNone("ab1", 'xyz')  = true
 * StringUtils.containsNone("abz", 'xyz')  = false
 * </pre>
 *
 * @param cs  the CharSequence to check, may be null
 * @param searchChars  an array of invalid chars, may be null
 * @return true if it contains none of the invalid chars, or is null
 * @since 2.0
 * @since 3.0 Changed signature from containsNone(String, char[]) to containsNone(CharSequence, char...)
 */
public static boolean containsNone(CharSequence cs, char... searchChars) {
    if (cs == null || searchChars == null) {
        return true;
    }
    int csLen = cs.length();
    int csLast = csLen - 1;
    int searchLen = searchChars.length;
    int searchLast = searchLen - 1;
    for (int i = 0; i < csLen; i++) {
        char ch = cs.charAt(i);
        for (int j = 0; j < searchLen; j++) {
            if (searchChars[j] == ch) {
                if (Character.isHighSurrogate(ch)) {
                    if (j == searchLast) {
                        // missing low surrogate, fine, like String.indexOf(String)
                        return false;
                    }
                    if (i < csLast && searchChars[j + 1] == cs.charAt(i + 1)) {
                        return false;
                    }
                } else {
                    // ch is in the Basic Multilingual Plane
                    return false;
                }
            }
        }
    }
    return true;
}

From source file:org.apache.commons.lang3.StringUtils.java

/**
 * <p>Search a CharSequence to find the first index of any
 * character in the given set of characters.</p>
 *
 * <p>A {@code null} String will return {@code -1}.
 * A {@code null} or zero length search array will return {@code -1}.</p>
 *
 * <pre>//from w  w  w. j a  v  a  2s.  com
 * StringUtils.indexOfAny(null, *)                = -1
 * StringUtils.indexOfAny("", *)                  = -1
 * StringUtils.indexOfAny(*, null)                = -1
 * StringUtils.indexOfAny(*, [])                  = -1
 * StringUtils.indexOfAny("zzabyycdxx",['z','a']) = 0
 * StringUtils.indexOfAny("zzabyycdxx",['b','y']) = 3
 * StringUtils.indexOfAny("aba", ['z'])           = -1
 * </pre>
 *
 * @param cs  the CharSequence to check, may be null
 * @param searchChars  the chars to search for, may be null
 * @return the index of any of the chars, -1 if no match or null input
 * @since 2.0
 * @since 3.0 Changed signature from indexOfAny(String, char[]) to indexOfAny(CharSequence, char...)
 */
public static int indexOfAny(CharSequence cs, char... searchChars) {
    if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
        return INDEX_NOT_FOUND;
    }
    int csLen = cs.length();
    int csLast = csLen - 1;
    int searchLen = searchChars.length;
    int searchLast = searchLen - 1;
    for (int i = 0; i < csLen; i++) {
        char ch = cs.charAt(i);
        for (int j = 0; j < searchLen; j++) {
            if (searchChars[j] == ch) {
                if (i < csLast && j < searchLast && Character.isHighSurrogate(ch)) {
                    // ch is a supplementary character
                    if (searchChars[j + 1] == cs.charAt(i + 1)) {
                        return i;
                    }
                } else {
                    return i;
                }
            }
        }
    }
    return INDEX_NOT_FOUND;
}

From source file:org.apache.commons.lang3.StringUtils.java

/**
 * <p>Searches a CharSequence to find the first index of any
 * character not in the given set of characters.</p>
 *
 * <p>A {@code null} CharSequence will return {@code -1}.
 * A {@code null} or zero length search array will return {@code -1}.</p>
 *
 * <pre>//from   ww w  .j  a  v  a  2s.c o  m
 * StringUtils.indexOfAnyBut(null, *)                              = -1
 * StringUtils.indexOfAnyBut("", *)                                = -1
 * StringUtils.indexOfAnyBut(*, null)                              = -1
 * StringUtils.indexOfAnyBut(*, [])                                = -1
 * StringUtils.indexOfAnyBut("zzabyycdxx", new char[] {'z', 'a'} ) = 3
 * StringUtils.indexOfAnyBut("aba", new char[] {'z'} )             = 0
 * StringUtils.indexOfAnyBut("aba", new char[] {'a', 'b'} )        = -1
        
 * </pre>
 *
 * @param cs  the CharSequence to check, may be null
 * @param searchChars  the chars to search for, may be null
 * @return the index of any of the chars, -1 if no match or null input
 * @since 2.0
 * @since 3.0 Changed signature from indexOfAnyBut(String, char[]) to indexOfAnyBut(CharSequence, char...)
 */
public static int indexOfAnyBut(CharSequence cs, char... searchChars) {
    if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
        return INDEX_NOT_FOUND;
    }
    int csLen = cs.length();
    int csLast = csLen - 1;
    int searchLen = searchChars.length;
    int searchLast = searchLen - 1;
    outer: for (int i = 0; i < csLen; i++) {
        char ch = cs.charAt(i);
        for (int j = 0; j < searchLen; j++) {
            if (searchChars[j] == ch) {
                if (i < csLast && j < searchLast && Character.isHighSurrogate(ch)) {
                    if (searchChars[j + 1] == cs.charAt(i + 1)) {
                        continue outer;
                    }
                } else {
                    continue outer;
                }
            }
        }
        return i;
    }
    return INDEX_NOT_FOUND;
}

From source file:org.apache.commons.lang3.StringUtils.java

/**
 * <p>Checks if the CharSequence contains any character in the given
 * set of characters.</p>//from ww w .  j av  a  2s  .  c o  m
 *
 * <p>A {@code null} CharSequence will return {@code false}.
 * A {@code null} or zero length search array will return {@code false}.</p>
 *
 * <pre>
 * StringUtils.containsAny(null, *)                = false
 * StringUtils.containsAny("", *)                  = false
 * StringUtils.containsAny(*, null)                = false
 * StringUtils.containsAny(*, [])                  = false
 * StringUtils.containsAny("zzabyycdxx",['z','a']) = true
 * StringUtils.containsAny("zzabyycdxx",['b','y']) = true
 * StringUtils.containsAny("aba", ['z'])           = false
 * </pre>
 *
 * @param cs  the CharSequence to check, may be null
 * @param searchChars  the chars to search for, may be null
 * @return the {@code true} if any of the chars are found,
 * {@code false} if no match or null input
 * @since 2.4
 * @since 3.0 Changed signature from containsAny(String, char[]) to containsAny(CharSequence, char...)
 */
public static boolean containsAny(CharSequence cs, char... searchChars) {
    if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
        return false;
    }
    int csLength = cs.length();
    int searchLength = searchChars.length;
    int csLast = csLength - 1;
    int searchLast = searchLength - 1;
    for (int i = 0; i < csLength; i++) {
        char ch = cs.charAt(i);
        for (int j = 0; j < searchLength; j++) {
            if (searchChars[j] == ch) {
                if (Character.isHighSurrogate(ch)) {
                    if (j == searchLast) {
                        // missing low surrogate, fine, like String.indexOf(String)
                        return true;
                    }
                    if (i < csLast && searchChars[j + 1] == cs.charAt(i + 1)) {
                        return true;
                    }
                } else {
                    // ch is in the Basic Multilingual Plane
                    return true;
                }
            }
        }
    }
    return false;
}

From source file:com.sjdf.platform.xss.StringUtils.java

/**
 * <p>//from   ww  w.  j ava2s  .c  o m
 * Checks if the CharSequence contains only Unicode digits or space (
 * {@code ' '}). A decimal point is not a Unicode digit and returns false.
 * </p>
 * <p/>
 * <p>
 * {@code null} will return {@code false}. An empty CharSequence
 * (length()=0) will return {@code true}.
 * </p>
 * <p/>
 * <pre>
 * StringUtils.isNumericSpace(null)   = false
 * StringUtils.isNumericSpace("")     = true
 * StringUtils.isNumericSpace("  ")   = true
 * StringUtils.isNumericSpace("123")  = true
 * StringUtils.isNumericSpace("12 3") = true
 * StringUtils.isNumericSpace("ab2c") = false
 * StringUtils.isNumericSpace("12-3") = false
 * StringUtils.isNumericSpace("12.3") = false
 * </pre>
 *
 * @param cs the CharSequence to check, may be null
 * @return {@code true} if only contains digits or space, and is non-null
 * @since 3.0 Changed signature from isNumericSpace(String) to
 * isNumericSpace(CharSequence)
 */
public static boolean isNumericSpace(CharSequence cs) {
    if (cs == null) {
        return false;
    }
    int sz = cs.length();
    for (int i = 0; i < sz; i++) {
        if (!Character.isDigit(cs.charAt(i)) && cs.charAt(i) != ' ') {
            return false;
        }
    }
    return true;
}

From source file:com.sjdf.platform.xss.StringUtils.java

/**
 * <p>/* www  .  ja v a  2 s  .c o  m*/
 * Checks if the CharSequence contains only Unicode letters and space (' ').
 * </p>
 * <p/>
 * <p>
 * {@code null} will return {@code false} An empty CharSequence (length()=0)
 * will return {@code true}.
 * </p>
 * <p/>
 * <pre>
 * StringUtils.isAlphaSpace(null)   = false
 * StringUtils.isAlphaSpace("")     = true
 * StringUtils.isAlphaSpace("  ")   = true
 * StringUtils.isAlphaSpace("abc")  = true
 * StringUtils.isAlphaSpace("ab c") = true
 * StringUtils.isAlphaSpace("ab2c") = false
 * StringUtils.isAlphaSpace("ab-c") = false
 * </pre>
 *
 * @param cs the CharSequence to check, may be null
 * @return {@code true} if only contains letters and space, and is non-null
 * @since 3.0 Changed signature from isAlphaSpace(String) to
 * isAlphaSpace(CharSequence)
 */
public static boolean isAlphaSpace(CharSequence cs) {
    if (cs == null) {
        return false;
    }
    int sz = cs.length();
    for (int i = 0; i < sz; i++) {
        if (!Character.isLetter(cs.charAt(i)) && cs.charAt(i) != ' ') {
            return false;
        }
    }
    return true;
}