Converts a Boolean to a boolean handling null by returning false. - Java java.lang

Java examples for java.lang:boolean

  1. HOME
  2. Java
  3. java.lang
  4. boolean

Description

Converts a Boolean to a boolean handling null by returning false.

Demo Code

/*/*from   w w  w  .  jav  a2  s . co 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 or the String is null
     */
    public static boolean toBoolean(String str) {
        return toBoolean(toBooleanObject(str));
    }

    /**
     * <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");
    }

    /**
     * <p>Boolean factory that avoids creating new Boolean objects all the time.</p>
     * 
     * <p>This method was added to JDK1.4 but is available here for earlier JDKs.</p>
     *
     * <pre>
     *   BooleanUtils.toBooleanObject(false) = Boolean.FALSE
     *   BooleanUtils.toBooleanObject(true)  = Boolean.TRUE
     * </pre>
     *
     * @param bool  the boolean to convert
     * @return Boolean.TRUE or Boolean.FALSE as appropriate
     */
    public static Boolean toBooleanObject(boolean bool) {
        return bool ? Boolean.TRUE : Boolean.FALSE;
    }

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

    /**
     * <p>Converts an Integer to a Boolean using the convention that <code>zero</code>
     * is <code>false</code>.</p>
     * 
     * <p><code>null</code> will be converted to <code>null</code>.</p>
     *
     * <pre>
     *   BooleanUtils.toBoolean(new Integer(0))    = Boolean.FALSE
     *   BooleanUtils.toBoolean(new Integer(1))    = Boolean.TRUE
     *   BooleanUtils.toBoolean(new Integer(null)) = null
     * </pre>
     *
     * @param value  the Integer to convert
     * @return Boolean.TRUE if non-zero, Boolean.FALSE if zero,
     *  <code>null</code> if <code>null</code> input
     */
    public static Boolean toBooleanObject(Integer value) {
        if (value == null) {
            return null;
        }
        return value.intValue() == 0 ? Boolean.FALSE : Boolean.TRUE;
    }

    /**
     * <p>Converts an int to a Boolean specifying the conversion values.</p>
     * 
     * <pre>
     *   BooleanUtils.toBooleanObject(0, 0, 2, 3) = Boolean.TRUE
     *   BooleanUtils.toBooleanObject(2, 1, 2, 3) = Boolean.FALSE
     *   BooleanUtils.toBooleanObject(3, 1, 2, 3) = null
     * </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>
     * @param nullValue  the value to to match for <code>null</code>
     * @return Boolean.TRUE, Boolean.FALSE, or <code>null</code>
     * @throws IllegalArgumentException if no match
     */
    public static Boolean toBooleanObject(int value, int trueValue,
            int falseValue, int nullValue) {
        if (value == trueValue) {
            return Boolean.TRUE;
        } else if (value == falseValue) {
            return Boolean.FALSE;
        } else if (value == nullValue) {
            return null;
        }
        // no match
        throw new IllegalArgumentException(
                "The Integer did not match any specified value");
    }

    /**
     * <p>Converts an Integer to a Boolean specifying the conversion values.</p>
     * 
     * <pre>
     *   BooleanUtils.toBooleanObject(new Integer(0), new Integer(0), new Integer(2), new Integer(3)) = Boolean.TRUE
     *   BooleanUtils.toBooleanObject(new Integer(2), new Integer(1), new Integer(2), new Integer(3)) = Boolean.FALSE
     *   BooleanUtils.toBooleanObject(new Integer(3), new Integer(1), new Integer(2), new Integer(3)) = null
     * </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>
     * @param nullValue  the value to to match for <code>null</code>,
     *  may be <code>null</code>
     * @return Boolean.TRUE, Boolean.FALSE, or <code>null</code>
     * @throws IllegalArgumentException if no match
     */
    public static Boolean toBooleanObject(Integer value, Integer trueValue,
            Integer falseValue, Integer nullValue) {
        if (value == null) {
            if (trueValue == null) {
                return Boolean.TRUE;
            } else if (falseValue == null) {
                return Boolean.FALSE;
            } else if (nullValue == null) {
                return null;
            }
        } else if (value.equals(trueValue)) {
            return Boolean.TRUE;
        } else if (value.equals(falseValue)) {
            return Boolean.FALSE;
        } else if (value.equals(nullValue)) {
            return null;
        }
        // no match
        throw new IllegalArgumentException(
                "The Integer did not match any specified value");
    }

    /**
     * <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>
     *
     * <pre>
     *   BooleanUtils.toBooleanObject(null)    = null
     *   BooleanUtils.toBooleanObject("true")  = Boolean.TRUE
     *   BooleanUtils.toBooleanObject("false") = Boolean.FALSE
     *   BooleanUtils.toBooleanObject("on")    = Boolean.TRUE
     *   BooleanUtils.toBooleanObject("ON")    = Boolean.TRUE
     *   BooleanUtils.toBooleanObject("off")   = Boolean.FALSE
     *   BooleanUtils.toBooleanObject("oFf")   = Boolean.FALSE
     *   BooleanUtils.toBooleanObject("blue")  = null
     * </pre>
     *
     * @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) {
        // 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 Boolean.TRUE;
        }
        if (str == null) {
            return null;
        }
        switch (str.length()) {
        case 1: {
            char ch0 = str.charAt(0);
            if ((ch0 == 'y' || ch0 == 'Y') || (ch0 == 't' || ch0 == 'T')) {
                return Boolean.TRUE;
            }
            if ((ch0 == 'n' || ch0 == 'N') || (ch0 == 'f' || ch0 == 'F')) {
                return Boolean.FALSE;
            }
            break;
        }
        case 2: {
            char ch0 = str.charAt(0);
            char ch1 = str.charAt(1);
            if ((ch0 == 'o' || ch0 == 'O') && (ch1 == 'n' || ch1 == 'N')) {
                return Boolean.TRUE;
            }
            if ((ch0 == 'n' || ch0 == 'N') && (ch1 == 'o' || ch1 == 'O')) {
                return Boolean.FALSE;
            }
            break;
        }
        case 3: {
            char ch0 = str.charAt(0);
            char ch1 = str.charAt(1);
            char ch2 = str.charAt(2);
            if ((ch0 == 'y' || ch0 == 'Y') && (ch1 == 'e' || ch1 == 'E')
                    && (ch2 == 's' || ch2 == 'S')) {
                return Boolean.TRUE;
            }
            if ((ch0 == 'o' || ch0 == 'O') && (ch1 == 'f' || ch1 == 'F')
                    && (ch2 == 'f' || ch2 == 'F')) {
                return Boolean.FALSE;
            }
            break;
        }
        case 4: {
            char ch0 = str.charAt(0);
            char ch1 = str.charAt(1);
            char ch2 = str.charAt(2);
            char ch3 = str.charAt(3);
            if ((ch0 == 't' || ch0 == 'T') && (ch1 == 'r' || ch1 == 'R')
                    && (ch2 == 'u' || ch2 == 'U')
                    && (ch3 == 'e' || ch3 == 'E')) {
                return Boolean.TRUE;
            }
            break;
        }
        case 5: {
            char ch0 = str.charAt(0);
            char ch1 = str.charAt(1);
            char ch2 = str.charAt(2);
            char ch3 = str.charAt(3);
            char ch4 = str.charAt(4);
            if ((ch0 == 'f' || ch0 == 'F') && (ch1 == 'a' || ch1 == 'A')
                    && (ch2 == 'l' || ch2 == 'L')
                    && (ch3 == 's' || ch3 == 'S')
                    && (ch4 == 'e' || ch4 == 'E')) {
                return Boolean.FALSE;
            }
            break;
        }
        }

        return null;
    }

    /**
     * <p>Converts a String to a Boolean throwing an exception if no match.</p>
     *
     * <pre>
     *   BooleanUtils.toBooleanObject("true", "true", "false", "null")  = Boolean.TRUE
     *   BooleanUtils.toBooleanObject("false", "true", "false", "null") = Boolean.FALSE
     *   BooleanUtils.toBooleanObject("null", "true", "false", "null")  = null
     * </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>
     * @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 either the String matches <code>nullString</code>
     *  or if <code>null</code> input and <code>nullString</code> is
     *  <code>null</code>
     * @throws IllegalArgumentException if the String doesn't match
     */
    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");
    }
}

Related Tutorials