- /*
- * 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;
-
- import org.apache.commons.collections.Transformer;
- import org.apache.commons.logging.Log;
- import org.apache.commons.logging.LogFactory;
-
- import java.lang.reflect.InvocationTargetException;
-
-
- /**
- * <p><code>Transformer</code> that outputs a property value.</p>
- *
- * <p>An implementation of <code>org.apache.commons.collections.Transformer</code> that transforms
- * the object provided by returning the value of a specified property of the object. The
- * constructor for <code>BeanToPropertyValueTransformer</code> requires the name of the property
- * that will be used in the transformation. The property can be a simple, nested, indexed, or
- * mapped property as defined by <code>org.apache.commons.beanutils.PropertyUtils</code>. If any
- * object in the property path specified by <code>propertyName</code> is <code>null</code> then the
- * outcome is based on the value of the <code>ignoreNull</code> attribute.
- * </p>
- *
- * <p>
- * A typical usage might look like:
- * <code><pre>
- * // create the transformer
- * BeanToPropertyValueTransformer transformer = new BeanToPropertyValueTransformer( "person.address.city" );
- *
- * // transform the Collection
- * Collection peoplesCities = CollectionUtils.collect( peopleCollection, transformer );
- * </pre></code>
- * </p>
- *
- * <p>
- * This would take a <code>Collection</code> of person objects and return a <code>Collection</code>
- * of objects which represents the cities in which each person lived. Assuming...
- * <ul>
- * <li>
- * The top level object in the <code>peeopleCollection</code> is an object which represents a
- * person.
- * </li>
- * <li>
- * The person object has a <code>getAddress()</code> method which returns an object which
- * represents a person's address.
- * </li>
- * <li>
- * The address object has a <code>getCity()</code> method which returns an object which
- * represents the city in which a person lives.
- * </li>
- * </ul>
- *
- * @author Norm Deane
- * @see org.apache.commons.beanutils.PropertyUtils
- * @see org.apache.commons.collections.Transformer
- */
- public class BeanToPropertyValueTransformer implements Transformer {
-
- /** For logging. */
- private final Log log = LogFactory.getLog(this.getClass());
-
- /** The name of the property that will be used in the transformation of the object. */
- private String propertyName;
-
- /**
- * <p>Should null objects on the property path throw an <code>IllegalArgumentException</code>?</p>
- * <p>
- * Determines whether <code>null</code> objects in the property path will genenerate an
- * <code>IllegalArgumentException</code> or not. If set to <code>true</code> then if any objects
- * in the property path evaluate to <code>null</code> then the
- * <code>IllegalArgumentException</code> throw by <code>PropertyUtils</code> will be logged but
- * not rethrown and <code>null</code> will be returned. If set to <code>false</code> then if any
- * objects in the property path evaluate to <code>null</code> then the
- * <code>IllegalArgumentException</code> throw by <code>PropertyUtils</code> will be logged and
- * rethrown.
- * </p>
- */
- private boolean ignoreNull;
-
- /**
- * Constructs a Transformer which does not ignore nulls.
- * Constructor which takes the name of the property that will be used in the transformation and
- * assumes <code>ignoreNull</code> to be <code>false</code>.
- *
- * @param propertyName The name of the property that will be used in the transformation.
- * @throws IllegalArgumentException If the <code>propertyName</code> is <code>null</code> or
- * empty.
- */
- public BeanToPropertyValueTransformer(String propertyName) {
- this(propertyName, false);
- }
-
- /**
- * Constructs a Transformer and sets ignoreNull.
- * Constructor which takes the name of the property that will be used in the transformation and
- * a boolean which determines whether <code>null</code> objects in the property path will
- * genenerate an <code>IllegalArgumentException</code> or not.
- *
- * @param propertyName The name of the property that will be used in the transformation.
- * @param ignoreNull Determines whether <code>null</code> objects in the property path will
- * genenerate an <code>IllegalArgumentException</code> or not.
- * @throws IllegalArgumentException If the <code>propertyName</code> is <code>null</code> or
- * empty.
- */
- public BeanToPropertyValueTransformer(String propertyName, boolean ignoreNull) {
- super();
-
- if ((propertyName != null) && (propertyName.length() > 0)) {
- this.propertyName = propertyName;
- this.ignoreNull = ignoreNull;
- } else {
- throw new IllegalArgumentException(
- "propertyName cannot be null or empty");
- }
- }
-
- /**
- * Returns the value of the property named in the transformer's constructor for
- * the object provided. If any object in the property path leading up to the target property is
- * <code>null</code> then the outcome will be based on the value of the <code>ignoreNull</code>
- * attribute. By default, <code>ignoreNull</code> is <code>false</code> and would result in an
- * <code>IllegalArgumentException</code> if an object in the property path leading up to the
- * target property is <code>null</code>.
- *
- * @param object The object to be transformed.
- * @return The value of the property named in the transformer's constructor for the object
- * provided.
- * @throws IllegalArgumentException If an IllegalAccessException, InvocationTargetException, or
- * NoSuchMethodException is thrown when trying to access the property specified on the object
- * provided. Or if an object in the property path provided is <code>null</code> and
- * <code>ignoreNull</code> is set to <code>false</code>.
- */
- public Object transform(Object object) {
-
- Object propertyValue = null;
-
- try {
- propertyValue = PropertyUtils.getProperty(object, propertyName);
- } catch (IllegalArgumentException e) {
- final String errorMsg = "Problem during transformation. Null value encountered in property path...";
-
- if (ignoreNull) {
- log.warn("WARNING: " + errorMsg, e);
- } else {
- log.error("ERROR: " + errorMsg, e);
- throw e;
- }
- } catch (IllegalAccessException e) {
- final String errorMsg = "Unable to access the property provided.";
- log.error(errorMsg, e);
- throw new IllegalArgumentException(errorMsg);
- } catch (InvocationTargetException e) {
- final String errorMsg = "Exception occurred in property's getter";
- log.error(errorMsg, e);
- throw new IllegalArgumentException(errorMsg);
- } catch (NoSuchMethodException e) {
- final String errorMsg = "No property found for name [" +
- propertyName + "]";
- log.error(errorMsg, e);
- throw new IllegalArgumentException(errorMsg);
- }
-
- return propertyValue;
- }
-
- /**
- * Returns the name of the property that will be used in the transformation of the bean.
- *
- * @return The name of the property that will be used in the transformation of the bean.
- */
- public String getPropertyName() {
- return propertyName;
- }
-
- /**
- * Returns the flag which determines whether <code>null</code> objects in the property path will
- * genenerate an <code>IllegalArgumentException</code> or not. If set to <code>true</code> then
- * if any objects in the property path evaluate to <code>null</code> then the
- * <code>IllegalArgumentException</code> throw by <code>PropertyUtils</code> will be logged but
- * not rethrown and <code>null</code> will be returned. If set to <code>false</code> then if any
- * objects in the property path evaluate to <code>null</code> then the
- * <code>IllegalArgumentException</code> throw by <code>PropertyUtils</code> will be logged and
- * rethrown.
- *
- * @return The flag which determines whether <code>null</code> objects in the property path will
- * genenerate an <code>IllegalArgumentException</code> or not.
- */
- public boolean isIgnoreNull() {
- return ignoreNull;
- }
- }