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Commons Beanutils example source code file (BooleanConverter.java)
The Commons Beanutils BooleanConverter.java source code/* * 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 org.apache.commons.beanutils.converters; import org.apache.commons.beanutils.ConversionException; /** * {@link org.apache.commons.beanutils.Converter} implementaion that handles conversion * to and from <b>Boolean objects. * {@link org.apache.commons.beanutils.Converter} implementaion that * handles conversion to and from <b>java.lang.Boolean objects. * <p> * Can be configured to either return a <i>default value or throw a * <code>ConversionException if a conversion error occurs. * <p> * By default any object whose string representation is one of the values * {"yes", "y", "true", "on", "1"} is converted to Boolean.TRUE, and * string representations {"no", "n", "false", "off", "0"} are converted * to Boolean.FALSE. The recognised true/false strings can be changed by: * <pre> * String[] trueStrings = {"oui", "o", "1"}; * String[] falseStrings = {"non", "n", "0"}; * Converter bc = new BooleanConverter(trueStrings, falseStrings); * ConvertUtils.register(bc, Boolean.class); * ConvertUtils.register(bc, Boolean.TYPE); * </pre> * In addition, it is recommended that the BooleanArrayConverter also be * modified to recognise the same set of values: * <pre> * Converter bac = new BooleanArrayConverter(bc, BooleanArrayConverter.NO_DEFAULT); * ConvertUtils.register(bac, bac.MODEL); * </pre> * </p> * * <p>Case is ignored when converting values to true or false. * * @author Craig R. McClanahan * @version $Revision: 801644 $ $Date: 2009-08-06 14:38:56 +0100 (Thu, 06 Aug 2009) $ * @since 1.3 */ public final class BooleanConverter extends AbstractConverter { // ----------------------------------------------------------- Constructors /** * Create a {@link org.apache.commons.beanutils.Converter} that will throw a {@link ConversionException} * if a conversion error occurs, ie the string value being converted is * not one of the known true strings, nor one of the known false strings. */ public BooleanConverter() { super(); } /** * Create a {@link org.apache.commons.beanutils.Converter} that will return the specified default value * if a conversion error occurs, ie the string value being converted is * not one of the known true strings, nor one of the known false strings. * * @param defaultValue The default value to be returned if the value * being converted is not recognised. This value may be null, in which * case null will be returned on conversion failure. When non-null, it is * expected that this value will be either Boolean.TRUE or Boolean.FALSE. * The special value BooleanConverter.NO_DEFAULT can also be passed here, * in which case this constructor acts like the no-argument one. */ public BooleanConverter(Object defaultValue) { super(); if (defaultValue != NO_DEFAULT) { setDefaultValue(defaultValue); } } /** * Create a {@link org.apache.commons.beanutils.Converter} that will throw a {@link ConversionException} * if a conversion error occurs, ie the string value being converted is * not one of the known true strings, nor one of the known false strings. * <p> * The provided string arrays are copied, so that changes to the elements * of the array after this call is made do not affect this object. * * @param trueStrings is the set of strings which should convert to the * value Boolean.TRUE. The value null must not be present. Case is * ignored. * * @param falseStrings is the set of strings which should convert to the * value Boolean.TRUE. The value null must not be present. Case is * ignored. * @since 1.8.0 */ public BooleanConverter(String[] trueStrings, String[] falseStrings) { super(); this.trueStrings = copyStrings(trueStrings); this.falseStrings = copyStrings(falseStrings); } /** * Create a {@link org.apache.commons.beanutils.Converter} that will return * the specified default value if a conversion error occurs. * <p> * The provided string arrays are copied, so that changes to the elements * of the array after this call is made do not affect this object. * * @param trueStrings is the set of strings which should convert to the * value Boolean.TRUE. The value null must not be present. Case is * ignored. * * @param falseStrings is the set of strings which should convert to the * value Boolean.TRUE. The value null must not be present. Case is * ignored. * * @param defaultValue The default value to be returned if the value * being converted is not recognised. This value may be null, in which * case null will be returned on conversion failure. When non-null, it is * expected that this value will be either Boolean.TRUE or Boolean.FALSE. * The special value BooleanConverter.NO_DEFAULT can also be passed here, * in which case an exception will be thrown on conversion failure. * @since 1.8.0 */ public BooleanConverter(String[] trueStrings, String[] falseStrings, Object defaultValue) { super(); this.trueStrings = copyStrings(trueStrings); this.falseStrings = copyStrings(falseStrings); if (defaultValue != NO_DEFAULT) { setDefaultValue(defaultValue); } } // ----------------------------------------------------- Static Variables /** * This is a special reference that can be passed as the "default object" * to the constructor to indicate that no default is desired. Note that * the value 'null' cannot be used for this purpose, as the caller may * want a null to be returned as the default. * @deprecated Use constructors without default value. */ public static final Object NO_DEFAULT = new Object(); // ----------------------------------------------------- Instance Variables /** * The set of strings that are known to map to Boolean.TRUE. */ private String[] trueStrings = {"true", "yes", "y", "on", "1"}; /** * The set of strings that are known to map to Boolean.FALSE. */ private String[] falseStrings = {"false", "no", "n", "off", "0"}; // --------------------------------------------------------- Protected Methods /** * Return the default type this <code>Converter handles. * * @return The default type this <code>Converter handles. * @since 1.8.0 */ protected Class getDefaultType() { return Boolean.class; } /** * Convert the specified input object into an output object of the * specified type. * * @param type is the type to which this value should be converted. In the * case of this BooleanConverter class, this value is ignored. * * @param value is the input value to be converted. The toString method * shall be invoked on this object, and the result compared (ignoring * case) against the known "true" and "false" string values. * * @return Boolean.TRUE if the value was a recognised "true" value, * Boolean.FALSE if the value was a recognised "false" value, or * the default value if the value was not recognised and the constructor * was provided with a default value. * * @throws Throwable if an error occurs converting to the specified type * @since 1.8.0 */ protected Object convertToType(Class type, Object value) throws Throwable { // All the values in the trueStrings and falseStrings arrays are // guaranteed to be lower-case. By converting the input value // to lowercase too, we can use the efficient String.equals method // instead of the less-efficient String.equalsIgnoreCase method. String stringValue = value.toString().toLowerCase(); for(int i=0; i<trueStrings.length; ++i) { if (trueStrings[i].equals(stringValue)) { return Boolean.TRUE; } } for(int i=0; i<falseStrings.length; ++i) { if (falseStrings[i].equals(stringValue)) { return Boolean.FALSE; } } throw new ConversionException("Can't convert value '" + value + "' to a Boolean"); } /** * This method creates a copy of the provided array, and ensures that * all the strings in the newly created array contain only lower-case * letters. * <p> * Using this method to copy string arrays means that changes to the * src array do not modify the dst array. */ private static String[] copyStrings(String[] src) { String[] dst = new String[src.length]; for(int i=0; i<src.length; ++i) { dst[i] = src[i].toLowerCase(); } return dst; } } Other Commons Beanutils examples (source code examples)Here is a short list of links related to this Commons Beanutils BooleanConverter.java source code file: |
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