Converts a Boolean to a boolean handling null by returning false. BooleanUtils.toBoolean(Boolean.TRUE) = true BooleanUtils.toBoolean(Boolean.FALSE) = false BooleanUtils.toBoolean(null) = false - Java java.lang

Description

Converts a Boolean to a boolean handling null by returning false. BooleanUtils.toBoolean(Boolean.TRUE) = true BooleanUtils.toBoolean(Boolean.FALSE) = false BooleanUtils.toBoolean(null) = false

Demo Code

/*//from ww  w.  ja  v  a2  s  . c o  m
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        boolean bool = true;
        System.out.println(toBoolean(bool));
    }

    /**
     * <p>Converts a Boolean to a boolean handling <code>null</code>
     * by returning <code>false</code>.</p>
     *
     * <pre>
     *   BooleanUtils.toBoolean(Boolean.TRUE)  = true
     *   BooleanUtils.toBoolean(Boolean.FALSE) = false
     *   BooleanUtils.toBoolean(null)          = false
     * </pre>
     *
     * @param bool  the boolean to convert
     * @return <code>true</code> or <code>false</code>, 
     *  <code>null</code> returns <code>false</code>
     */
    public static boolean toBoolean(Boolean bool) {
        if (bool == null) {
            return false;
        }
        return bool.booleanValue() ? true : false;
    }

    /**
     * <p>Converts an int to a boolean using the convention that <code>zero</code>
     * is <code>false</code>.</p>
     *
     * <pre>
     *   BooleanUtils.toBoolean(0) = false
     *   BooleanUtils.toBoolean(1) = true
     *   BooleanUtils.toBoolean(2) = true
     * </pre>
     *
     * @param value  the int to convert
     * @return <code>true</code> if non-zero, <code>false</code>
     *  if zero
     */
    public static boolean toBoolean(int value) {
        return value == 0 ? false : true;
    }

    /**
     * <p>Converts an int to a boolean specifying the conversion values.</p>
     *
     * <pre>
     *   BooleanUtils.toBoolean(0, 1, 0) = false
     *   BooleanUtils.toBoolean(1, 1, 0) = true
     *   BooleanUtils.toBoolean(2, 1, 2) = false
     *   BooleanUtils.toBoolean(2, 2, 0) = true
     * </pre>
     *
     * @param value  the Integer to convert
     * @param trueValue  the value to match for <code>true</code>
     * @param falseValue  the value to match for <code>false</code>
     * @return <code>true</code> or <code>false</code>
     * @throws IllegalArgumentException if no match
     */
    public static boolean toBoolean(int value, int trueValue, int falseValue) {
        if (value == trueValue) {
            return true;
        } else if (value == falseValue) {
            return false;
        }
        // no match
        throw new IllegalArgumentException(
                "The Integer did not match either specified value");
    }

    /**
     * <p>Converts an Integer to a boolean specifying the conversion values.</p>
     *
     * <pre>
     *   BooleanUtils.toBoolean(new Integer(0), new Integer(1), new Integer(0)) = false
     *   BooleanUtils.toBoolean(new Integer(1), new Integer(1), new Integer(0)) = true
     *   BooleanUtils.toBoolean(new Integer(2), new Integer(1), new Integer(2)) = false
     *   BooleanUtils.toBoolean(new Integer(2), new Integer(2), new Integer(0)) = true
     *   BooleanUtils.toBoolean(null, null, new Integer(0))                     = true
     * </pre>
     *
     * @param value  the Integer to convert
     * @param trueValue  the value to match for <code>true</code>,
     *  may be <code>null</code>
     * @param falseValue  the value to match for <code>false</code>,
     *  may be <code>null</code>
     * @return <code>true</code> or <code>false</code>
     * @throws IllegalArgumentException if no match
     */
    public static boolean toBoolean(Integer value, Integer trueValue,
            Integer falseValue) {
        if (value == null) {
            if (trueValue == null) {
                return true;
            } else if (falseValue == null) {
                return false;
            }
        } else if (value.equals(trueValue)) {
            return true;
        } else if (value.equals(falseValue)) {
            return false;
        }
        // no match
        throw new IllegalArgumentException(
                "The Integer did not match either specified value");
    }

    /**
     * <p>Converts a String to a boolean (optimised for performance).</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>
     *
     * <p>This method performs 4 times faster (JDK1.4) than
     * <code>Boolean.valueOf(String)</code>. However, this method accepts
     * 'on' and 'yes' as true values.
     *
     * <pre>
     *   BooleanUtils.toBoolean(null)    = false
     *   BooleanUtils.toBoolean("true")  = true
     *   BooleanUtils.toBoolean("TRUE")  = true
     *   BooleanUtils.toBoolean("tRUe")  = true
     *   BooleanUtils.toBoolean("on")    = true
     *   BooleanUtils.toBoolean("yes")   = true
     *   BooleanUtils.toBoolean("false") = false
     *   BooleanUtils.toBoolean("x gti") = false
     * </pre>
     *
     * @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) {
        // Previously used equalsIgnoreCase, which was fast for interned 'true'.
        // Non interned 'true' matched 15 times slower.
        // 
        // Optimisation provides same performance as before for interned 'true'.
        // Similar performance for null, 'false', and other strings not length 2/3/4.
        // 'true'/'TRUE' match 4 times slower, 'tRUE'/'True' 7 times slower.
        if (str == "true") {
            return true;
        }
        if (str == null) {
            return false;
        }
        switch (str.length()) {
        case 2: {
            char ch0 = str.charAt(0);
            char ch1 = str.charAt(1);
            return (ch0 == 'o' || ch0 == 'O') && (ch1 == 'n' || ch1 == 'N');
        }
        case 3: {
            char ch = str.charAt(0);
            if (ch == 'y') {
                return (str.charAt(1) == 'e' || str.charAt(1) == 'E')
                        && (str.charAt(2) == 's' || str.charAt(2) == 'S');
            }
            if (ch == 'Y') {
                return (str.charAt(1) == 'E' || str.charAt(1) == 'e')
                        && (str.charAt(2) == 'S' || str.charAt(2) == 's');
            }
            return false;
        }
        case 4: {
            char ch = str.charAt(0);
            if (ch == 't') {
                return (str.charAt(1) == 'r' || str.charAt(1) == 'R')
                        && (str.charAt(2) == 'u' || str.charAt(2) == 'U')
                        && (str.charAt(3) == 'e' || str.charAt(3) == 'E');
            }
            if (ch == 'T') {
                return (str.charAt(1) == 'R' || str.charAt(1) == 'r')
                        && (str.charAt(2) == 'U' || str.charAt(2) == 'u')
                        && (str.charAt(3) == 'E' || str.charAt(3) == 'e');
            }
        }
        }
        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>
     *
     * <pre>
     *   BooleanUtils.toBoolean("true", "true", "false")  = true
     *   BooleanUtils.toBoolean("false", "true", "false") = false
     * </pre>
     *
     * @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");
    }
}

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