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Commons Beanutils example source code file (BooleanArrayConverter.java)

This example Commons Beanutils source code file (BooleanArrayConverter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Beanutils tags/keywords

boolean, booleanarrayconverter, booleanarrayconverter, booleanconverter, conversionexception, default_converter, default_converter, exception, model, no, object, object, string, string, util

The Commons Beanutils BooleanArrayConverter.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 java.util.List;
import org.apache.commons.beanutils.ConversionException;


/**
 * <p>Standard {@link org.apache.commons.beanutils.Converter} implementation that converts an incoming
 * String into a primitive array of boolean.  On a conversion failure, returns
 * a specified default value or throws a {@link ConversionException} depending
 * on how this instance is constructed.</p>
 *
 * <p>By default, the values to be converted are expected to be those
 * recognised by a default instance of BooleanConverter. A customised
 * BooleanConverter can be provided in order to recognise alternative values
 * as true/false. </p>
 *
 * @author Craig R. McClanahan
 * @version $Revision: 690380 $ $Date: 2008-08-29 21:04:38 +0100 (Fri, 29 Aug 2008) $
 * @since 1.4
 * @deprecated Replaced by the new {@link ArrayConverter} implementation
 */

public final class BooleanArrayConverter extends AbstractArrayConverter {


    // ----------------------------------------------------------- Constructors


    /**
     * Create a {@link org.apache.commons.beanutils.Converter} that will throw
     * a {@link ConversionException} if a conversion error occurs.
     *
     * <p>Conversion of strings to boolean values will be done via a default
     * instance of class BooleanConverter.</p>
     */
    public BooleanArrayConverter() {

        super();
        this.booleanConverter = DEFAULT_CONVERTER;

    }


    /**
     * Create a {@link org.apache.commons.beanutils.Converter} that will return
     * the specified default value if a conversion error occurs.
     *
     * <p>Conversion of strings to boolean values will be done via a default
     * instance of class BooleanConverter.</p>
     *
     * @param defaultValue The default value to be returned
     */
    public BooleanArrayConverter(Object defaultValue) {

        super(defaultValue);
        this.booleanConverter = DEFAULT_CONVERTER;

    }


    /**
     * Create a {@link org.apache.commons.beanutils.Converter} that will return
     * the specified default value if a conversion error occurs.
     *
     * <p>Conversion of strings to boolean values will be done via the
     * specified converter.</p>
     *
     * @param converter is the converter object that will be used to
     *  convert each input string-value into a boolean.
     *
     * @param defaultValue is the default value to be returned by method
     * convert if conversion fails; null is a valid default value. See the
     * documentation for method "convert" for more information.
     * The value BooleanArrayConverter.NO_DEFAULT may be passed here to
     * specify that an exception should be thrown on conversion failure.
     *  
     */
    public BooleanArrayConverter(BooleanConverter converter, Object defaultValue) {

        super(defaultValue);
        this.booleanConverter = converter;

    }

    // ------------------------------------------------------- Static Variables

    /**
     * Type which this class converts its input to. This value can be
     * used as a parameter to the ConvertUtils.register method.
     * @since 1.8.0
     */
    public static final Class MODEL = new boolean[0].getClass();

    /**
     * The converter that all instances of this class will use to
     * do individual string->boolean conversions, unless overridden
     * in the constructor.
     */
    private static final BooleanConverter DEFAULT_CONVERTER
        = new BooleanConverter();

    // ---------------------------------------------------- Instance Variables

    /**
     * This object is used to perform the conversion of individual strings
     * into Boolean/boolean values.
     */
    protected final BooleanConverter booleanConverter;

    // --------------------------------------------------------- Public Methods


    /**
     * Convert the specified input object into an output object of type
     * array-of-boolean.
     * 
     * <p>If the input value is null, then the default value specified in the
     * constructor is returned. If no such value was provided, then a
     * ConversionException is thrown instead.</p>
     *
     * <p>If the input value is of type String[] then the returned array shall
     * be of the same size as this array, with a true or false value in each
     * array element depending on the result of applying method
     * BooleanConverter.convert to each string.</p>
     *
     * <p>For all other types of value, the object's toString method is
     * expected to return a string containing a comma-separated list of
     * values, eg "true, false, true". See the documentation for
     * {@link AbstractArrayConverter#parseElements} for more information on
     * the exact formats supported.</p>
     *
     * <p>If the result of value.toString() cannot be split into separate
     * words, then the default value is also returned (or an exception thrown).
     * </p>
     *
     * <p>If any of the elements in the value array (or the elements resulting
     * from splitting up value.toString) are not recognised by the
     * BooleanConverter associated with this object, then what happens depends
     * on whether that BooleanConverter has a default value or not: if it does, 
     * then that unrecognised element is converted into the BooleanConverter's
     * default value. If the BooleanConverter does <i>not have a default
     * value, then the default value for this object is returned as the
     * <i>complete conversion result (not just for the element), or an 
     * exception is thrown if this object has no default value defined.</p>
     *
     * @param type is the type to which this value should be converted. In the
     *  case of this BooleanArrayConverter class, this value is ignored.
     *
     * @param value is the input value to be converted.
     *
     * @return an object of type boolean[], or the default value if there was
     *  any sort of error during conversion and the constructor
     *  was provided with a default value.
     *
     * @exception ConversionException if conversion cannot be performed
     *  successfully and the constructor was not provided with a default
     *  value to return on conversion failure.
     *
     * @exception NullPointerException if value is an array, and any of the
     * array elements are null.
     */
    public Object convert(Class type, Object value) {

        // Deal with a null value
        if (value == null) {
            if (useDefault) {
                return (defaultValue);
            } else {
                throw new ConversionException("No value specified");
            }
        }

        // Deal with the no-conversion-needed case
        if (MODEL == value.getClass()) {
            return (value);
        }

        // Deal with input value as a String array
        //
        // TODO: use if (value.getClass().isArray() instead...
        //  this requires casting to Object[], then using values[i].toString()
        if (strings.getClass() == value.getClass()) {
            try {
                String[] values = (String[]) value;
                boolean[] results = new boolean[values.length];
                for (int i = 0; i < values.length; i++) {
                    String stringValue = values[i];
                    Object result = booleanConverter.convert(Boolean.class, stringValue);
                    results[i] = ((Boolean) result).booleanValue();
                }
                return (results);
            } catch (Exception e) {
                if (useDefault) {
                    return (defaultValue);
                } else {
                    throw new ConversionException(value.toString(), e);
                }
            }
        }

        // We only get here if the input value is not of type String[].
        // In this case, we assume value.toString() returns a comma-separated
        // sequence of values; see method AbstractArrayConverter.parseElements
        // for more information.
        try {
            List list = parseElements(value.toString());
            boolean[] results = new boolean[list.size()];
            for (int i = 0; i < results.length; i++) {
                String stringValue = (String) list.get(i);
                Object result = booleanConverter.convert(Boolean.class, stringValue);
                results[i] = ((Boolean) result).booleanValue();
            }
            return (results);
        } catch (Exception e) {
            if (useDefault) {
                return (defaultValue);
            } else {
                throw new ConversionException(value.toString(), e);
            }
        }

    }


}

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