Java tutorial
/* * 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. */ package org.apache.commons.beanutils.converters; import org.apache.commons.beanutils.ConversionException; import org.apache.commons.beanutils.Converter; /** * <p>Standard {@link Converter} implementation that converts an incoming * String into a <code>java.lang.Byte</code> object, optionally using a * default value or throwing a {@link ConversionException} if a conversion * error occurs.</p> * * @author Craig R. McClanahan * @version $Revision: 1.9 $ $Date: 2004/02/28 13:18:34 $ * @since 1.3 */ public final class ByteConverter implements Converter { // ----------------------------------------------------------- Constructors /** * Create a {@link Converter} that will throw a {@link ConversionException} * if a conversion error occurs. */ public ByteConverter() { this.defaultValue = null; this.useDefault = false; } /** * Create a {@link Converter} that will return the specified default value * if a conversion error occurs. * * @param defaultValue The default value to be returned */ public ByteConverter(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 * * @exception 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"); } } // System.err.println("VALUE=" + value + ", TYPE=" + value.getClass().getName()); if (value instanceof Byte) { return (value); } else if (value instanceof Number) { return new Byte(((Number) value).byteValue()); } try { return (new Byte(value.toString())); } catch (Exception e) { if (useDefault) { return (defaultValue); } else { throw new ConversionException(e); } } } }