booleanutils.java

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     * <p>Converts a Boolean to an int specifying the conversion values.</p>
     * 
     * @param bool  the Boolean to convert
     * @param trueValue  the value to return if <code>true</code>
     * @param falseValue  the value to return if <code>false</code>
     * @param nullValue  the value to return if <code>null</code>
     * @return the appropriate value
     */
    public static int toInteger(Boolean bool, int trueValue, int falseValue, int nullValue) {
        if (bool == null) {
            return nullValue;
        }
        return (bool.booleanValue() ? trueValue : falseValue);
    }
    
    /**
     * <p>Converts a boolean to an Integer specifying the conversion values.</p>
     * 
     * @param bool  the to convert
     * @param trueValue  the value to return if <code>true</code>,
     *  may be <code>null</code>
     * @param falseValue  the value to return if <code>false</code>,
     *  may be <code>null</code>
     * @return the appropriate value
     */
    public static Integer toIntegerObject(boolean bool, Integer trueValue, Integer falseValue) {
        return (bool ? trueValue : falseValue);
    }
    
    /**
     * <p>Converts a Boolean to an Integer specifying the conversion values.</p>
     * 
     * @param bool  the Boolean to convert
     * @param trueValue  the value to return if <code>true</code>,
     *  may be <code>null</code>
     * @param falseValue  the value to return if <code>false</code>,
     *  may be <code>null</code>
     * @param nullValue  the value to return if <code>null</code>,
     *  may be <code>null</code>
     * @return the appropriate value
     */
    public static Integer toIntegerObject(Boolean bool, Integer trueValue, Integer falseValue, Integer nullValue) {
        if (bool == null) {
            return nullValue;
        }
        return (bool.booleanValue() ? trueValue : falseValue);
    }
    
    // String to Boolean methods
    //-----------------------------------------------------------------------
    /**
     * <p>Converts a String to a Boolean.</p>
     * 
     * <p><code>'true'</code>, <code>'on'</code> or <code>'yes'</code>
     * (case insensitive) will return <code>true</code>.
     * <code>'false'</code>, <code>'off'</code> or <code>'no'</code>
     * (case insensitive) will return <code>false</code>.
     * Otherwise, <code>null</code> is returned.</p>
     *
     * @param str  the String to check
     * @return the Boolean value of the string,
     *  <code>null</code> if no match or <code>null</code> input
     */
    public static Boolean toBooleanObject(String str) {
        if ("true".equalsIgnoreCase(str)) {
            return Boolean.TRUE;
        } else if ("false".equalsIgnoreCase(str)) {
            return Boolean.FALSE;
        } else if ("on".equalsIgnoreCase(str)) {
            return Boolean.TRUE;
        } else if ("off".equalsIgnoreCase(str)) {
            return Boolean.FALSE;
        } else if ("yes".equalsIgnoreCase(str)) {
            return Boolean.TRUE;
        } else if ("no".equalsIgnoreCase(str)) {
            return Boolean.FALSE;
        }
        // no match
        return null;
    }

    /**
     * <p>Converts a String to a Boolean throwing an exception if no match.</p>
     *
     * @param str  the String to check
     * @param trueString  the String to match for <code>true</code>
     *  (case sensitive), may be <code>null</code>
     * @param falseString  the String to match for <code>false</code>
     *  (case sensitive), may be <code>null</code>
     * @param nullString  the String to match for <code>null</code>
     *  (case sensitive), may be <code>null</code>
     * @return the Boolean value of the string,
     *  <code>null</code> if no match or <code>null</code> input
     */
    public static Boolean toBooleanObject(String str, String trueString, String falseString, String nullString) {
        if (str == null) {
            if (trueString == null) {
                return Boolean.TRUE;
            } else if (falseString == null) {
                return Boolean.FALSE;
            } else if (nullString == null) {
                return null;
            }
        } else if (str.equals(trueString)) {
            return Boolean.TRUE;
        } else if (str.equals(falseString)) {
            return Boolean.FALSE;
        } else if (str.equals(nullString)) {
            return null;
        }
        // no match
        throw new IllegalArgumentException("The String did not match any specified value");
    }

    // String to boolean methods
    //-----------------------------------------------------------------------
    /**
     * <p>Converts a String to a boolean.</p>
     * 
     * <p><code>'true'</code>, <code>'on'</code> or <code>'yes'</code>
     * (case insensitive) will return <code>true</code>. Otherwise,
     * <code>false</code> is returned.</p>
     *
     * @param str  the String to check
     * @return the boolean value of the string, <code>false</code> if no match
     */
    public static boolean toBoolean(String str) {
        if ("true".equalsIgnoreCase(str)) {
            return true;
        } else if ("on".equalsIgnoreCase(str)) {
            return true;
        } else if ("yes".equalsIgnoreCase(str)) {
            return true;
        }
        // no match
        return false;
    }

    /**
     * <p>Converts a String to a Boolean throwing an exception if no match found.</p>
     * 
     * <p>null is returned if there is no match.</p>
     *
     * @param str  the String to check
     * @param trueString  the String to match for <code>true</code>
     *  (case sensitive), may be <code>null</code>
     * @param falseString  the String to match for <code>false</code>
     *  (case sensitive), may be <code>null</code>
     * @return the boolean value of the string
     * @throws IllegalArgumentException if the String doesn't match
     */
    public static boolean toBoolean(String str, String trueString, String falseString) {
        if (str == null) {
            if (trueString == null) {
                return true;
            } else if (falseString == null) {
                return false;
            }
        } else if (str.equals(trueString)) {
            return true;
        } else if (str.equals(falseString)) {
            return false;
        }
        // no match
        throw new IllegalArgumentException("The String did not match either specified value");
    }

    // Boolean to String methods
    //-----------------------------------------------------------------------
    /**
     * <p>Converts a Boolean to a String returning <code>'true'</code>,
     * <code>'false'</code>, or <code>null</code>.</p>
     * 
     * @param bool  the Boolean to check
     * @return <code>'true'</code>, <code>'false'</code>,
     *  or <code>null</code>
     */
    public static String toStringTrueFalse(Boolean bool) {
        return toString(bool, "true", "false", null);
    }
    
    /**
     * <p>Converts a Boolean to a String returning <code>'on'</code>,
     * <code>'off'</code>, or <code>null</code>.</p>
     * 
     * @param bool  the Boolean to check
     * @return <code>'on'</code>, <code>'off'</code>,
     *  or <code>null</code>
     */
    public static String toStringOnOff(Boolean bool) {
        return toString(bool, "on", "off", null);
    }
    
    /**
     * <p>Converts a Boolean to a String returning <code>'yes'</code>,
     * <code>'no'</code>, or <code>null</code>.</p>
     * 
     * @param bool  the Boolean to check
     * @return <code>'yes'</code>, <code>'no'</code>,
     *  or <code>null</code>
     */
    public static String toStringYesNo(Boolean bool) {
        return toString(bool, "yes", "no", null);
    }
    
    /**
     * <p>Converts a Boolean to a String returning one of the input Strings.</p>
     * 
     * @param bool  the Boolean to check
     * @param trueString  the String to return if <code>true</code>,
     *  may be <code>null</code>
     * @param falseString  the String to return if <code>false</code>,
     *  may be <code>null</code>
     * @param nullString  the String to return if <code>null</code>,
     *  may be <code>null</code>
     * @return one of the three input Strings
     */
    public static String toString(Boolean bool, String trueString, String falseString, String nullString) {
        if (bool == null) {
            return nullString;
        }
        return (bool.booleanValue() ? trueString : falseString);
    }
    
    // boolean to String methods
    //-----------------------------------------------------------------------
    /**
     * <p>Converts a boolean to a String returning <code>'true'</code>
     * or <code>'false'</code>.</p>
     * 
     * @param bool  the Boolean to check
     * @return <code>'true'</code>, <code>'false'</code>,
     *  or <code>null</code>
     */
    public static String toStringTrueFalse(boolean bool) {
        return toString(bool, "true", "false");
    }
    
    /**
     * <p>Converts a boolean to a String returning <code>'on'</code>
     * or <code>'off'</code>.</p>
     * 
     * @param bool  the Boolean to check
     * @return <code>'on'</code>, <code>'off'</code>,
     *  or <code>null</code>
     */
    public static String toStringOnOff(boolean bool) {
        return toString(bool, "on", "off");
    }
    
    /**
     * <p>Converts a boolean to a String returning <code>'yes'</code>
     * or <code>'no'</code>.</p>
     * 
     * @param bool  the Boolean to check
     * @return <code>'yes'</code>, <code>'no'</code>,
     *  or <code>null</code>
     */
    public static String toStringYesNo(boolean bool) {
        return toString(bool, "yes", "no");
    }
    
    /**
     * <p>Converts a boolean to a String returning one of the input Strings.</p>
     * 
     * @param bool  the Boolean to check
     * @param trueString  the String to return if <code>true</code>,
     *  may be <code>null</code>
     * @param falseString  the String to return if <code>false</code>,
     *  may be <code>null</code>
     * @return one of the two input Strings
     */
    public static String toString(boolean bool, String trueString, String falseString) {
        return (bool ? trueString : falseString);
    }
    
    // xor methods
    // ----------------------------------------------------------------------
    /**
     * <p>Performs an xor on a set of booleans.</p>
     * 
     * @param array  an array of <code>boolean<code>s
     * @return <code>true</code> if the xor is successful.
     * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
     * @throws IllegalArgumentException if <code>array</code> is empty.
     */
    public static boolean xor(boolean[] array) {
        // Validates input
        if (array == null) {
            throw new IllegalArgumentException("The Array must not be null");
        } else if (array.length == 0) {
            throw new IllegalArgumentException("Array is empty");
        }

        // Loops through array, comparing each item
        int trueCount = 0;
        for (int i = 0; i < array.length; i++) {
            // If item is true, and trueCount is < 1, increments count
            // Else, xor fails
            if (array[i]) {
                if (trueCount < 1) {
                    trueCount++;
                } else {
                    return false;
                }
            }
        }

        // Returns true if there was exactly 1 true item
        return trueCount == 1;
    }

    /**
     * <p>Performs an xor on an array of Booleans.</p>
     * 
     * @param array  an array of <code>Boolean<code>s
     * @return <code>true</code> if the xor is successful.
     * @throws IllegalArgumentException if <code>array</code> is <code>null</code>
     * @throws IllegalArgumentException if <code>array</code> is empty.
     * @throws IllegalArgumentException if <code>array</code> contains a <code>null</code>
     */
    public static Boolean xor(Boolean[] array) {
        if (array == null) {
            throw new IllegalArgumentException("The Array must not be null");
        } else if (array.length == 0) {
            throw new IllegalArgumentException("Array is empty");
        }
        boolean[] primitive = null;
        try {
            primitive = ArrayUtils.toPrimitive(array);
        } catch (NullPointerException ex) {
            throw new IllegalArgumentException("The array must not conatin any null elements");
        }
        return (xor(primitive) ? Boolean.TRUE : Boolean.FALSE);
    }

}