com.pdpsoft.web.DoubleConverter.java Source code

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Here is the source code for com.pdpsoft.web.DoubleConverter.java

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package com.pdpsoft.web;
/*
   * Copyright 2001-2004 The Apache Software Foundation.
   *
   * Licensed 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.
   */

import org.apache.commons.beanutils.ConversionException;
import org.apache.commons.beanutils.Converter;
import org.apache.commons.lang.StringUtils;

/**
 * <p>Standard {@link org.apache.commons.beanutils.Converter} implementation that converts an incoming
 * String into a <code>java.lang.Double</code> object, optionally using a
 * default value or throwing a {@link org.apache.commons.beanutils.ConversionException} if a conversion
 * error occurs.</p>
 *
 * @author Craig R. McClanahan
 * @version $Revision: 1.8 $ $Date: 2004/02/28 13:18:34 $
 * @since 1.3
 */

/**
 * Created by IntelliJ IDEA.
 * User: ChrisShayan.com
 * Date: May 20, 2009
 * Time: 6:34:58 PM
 */
public final class DoubleConverter implements Converter {

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

    /**
     * Create a {@link org.apache.commons.beanutils.Converter} that will throw a {@link org.apache.commons.beanutils.ConversionException}
     * if a conversion error occurs.
     */
    public DoubleConverter() {

        this.defaultValue = null;
        this.useDefault = false;
    }

    /**
     * Create a {@link org.apache.commons.beanutils.Converter} that will return the specified default value
     * if a conversion error occurs.
     *
     * @param defaultValue The default value to be returned
     */
    public DoubleConverter(Object defaultValue) {

        this.defaultValue = defaultValue;
        this.useDefault = true;

    }

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

    /**
     * The default value specified to our Constructor, if any.
     */
    private Object defaultValue = null;

    /**
     * Should we return the default value on conversion errors?
     */
    private boolean useDefault = true;

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

    /**
     * Convert the specified input object into an output object of the
     * specified type.
     *
     * @param type  Data type to which this value should be converted
     * @param value The input value to be converted
     * @throws org.apache.commons.beanutils.ConversionException if conversion cannot be performed
     *                             successfully
     */
    public Object convert(Class type, Object value) {
        if (value == null) {
            if (useDefault) {
                return (defaultValue);
            } else {
                throw new ConversionException("No value specified");
            }
        }

        if (value instanceof Double) {
            return (value);
        } else if (value instanceof Number) {
            return ((Number) value).doubleValue();
        }

        try {
            // avoid to return 0
            if (StringUtils.isEmpty(String.valueOf(value))) {
                return null;
            } else
                return (new Double(value.toString()));
        } catch (Exception e) {
            if (useDefault) {
                return (defaultValue);
            } else {
                throw new ConversionException(e);
            }
        }

    }
}