BeanUtilsBean.java

/*
 * 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.beanutils2;

import java.beans.IndexedPropertyDescriptor;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;

import org.apache.commons.beanutils2.expression.Resolver;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * TODO docs
 *
 * <p>
 * 2.0
 * </p>
 *
 * <p>
 * {@link BeanUtilsBean} implementation that creates a {@link ConvertUtilsBean} and delegates conversion to {@link ConvertUtilsBean#convert(Object, Class)}.
 * </p>
 *
 * <p>
 * To configure this implementation for the current context ClassLoader invoke {@code BeanUtilsBean.setInstance(new BeanUtilsBean2());}
 * </p>
 *
 * <p>
 * BeanUtils 1.7.0 delegated all conversion to String to the converter registered for the {@code String.class}. One of the improvements in BeanUtils 1.8.0 was
 * to upgrade the {@link Converter} implementations so that they could handle conversion to String for their type (for example IntegerConverter now handles
 * conversion from an Integer to a String as well as String to Integer).
 * </p>
 *
 * <p>
 * In order to take advantage of these improvements BeanUtils needs to change how it gets the appropriate {@link Converter}. This functionality has been
 * implemented in the new {@link ConvertUtilsBean#lookup(Class, Class)} and {@link ConvertUtilsBean#convert(Object, Class)} methods. However changing
 * {@link BeanUtilsBean} to use these methods could create compatibility issues for existing users. In order to avoid that, this new {@link BeanUtilsBean}
 * implementation has been created (and the associated {@link ConvertUtilsBean}).
 * </p>
 *
 * <p>
 * Pre-2.0
 * </p>
 *
 * <p>
 * JavaBean property population methods.
 * </p>
 *
 * <p>
 * This class provides implementations for the utility methods in {@link BeanUtils}. Different instances can be used to isolate caches between class loaders and
 * to vary the value converters registered.
 * </p>
 *
 * @see BeanUtils
 * @since 1.7
 */
public class BeanUtilsBean {

    /**
     * Contains {@code BeanUtilsBean} instances indexed by context classloader.
     */
    private static final ContextClassLoaderLocal<BeanUtilsBean> BEANS_BY_CLASSLOADER = new ContextClassLoaderLocal<BeanUtilsBean>() {
        // Creates the default instance used when the context classloader is unavailable
        @Override
        protected BeanUtilsBean initialValue() {
            return new BeanUtilsBean();
        }
    };

    /**
     * Logging for this instance
     */
    private static final Log LOG = LogFactory.getLog(BeanUtilsBean.class);

    /**
     * Determines the type of a {@code DynaProperty}. Here a special treatment is needed for mapped properties.
     *
     * @param dynaProperty the property descriptor
     * @param value        the value object to be set for this property
     * @return the type of this property
     */
    private static Class<?> dynaPropertyType(final DynaProperty dynaProperty, final Object value) {
        if (!dynaProperty.isMapped()) {
            return dynaProperty.getType();
        }
        return value == null ? String.class : value.getClass();
    }

    /**
     * Gets the instance which provides the functionality for {@link BeanUtils}. This is a pseudo-singleton - an single instance is provided per (thread)
     * context classloader. This mechanism provides isolation for web apps deployed in the same container.
     *
     * @return The (pseudo-singleton) BeanUtils bean instance
     */
    public static BeanUtilsBean getInstance() {
        return BEANS_BY_CLASSLOADER.get();
    }

    /**
     * Sets the instance which provides the functionality for {@link BeanUtils}. This is a pseudo-singleton - an single instance is provided per (thread)
     * context classloader. This mechanism provides isolation for web apps deployed in the same container.
     *
     * @param newInstance The (pseudo-singleton) BeanUtils bean instance
     */
    public static void setInstance(final BeanUtilsBean newInstance) {
        BEANS_BY_CLASSLOADER.set(newInstance);
    }

    /** Used to perform conversions between object types when setting properties */
    private final ConvertUtilsBean convertUtilsBean;

    /** Used to access properties */
    private final PropertyUtilsBean propertyUtilsBean;

    /**
     * <p>
     * Constructs an instance using new property and conversion instances.
     * </p>
     */
    public BeanUtilsBean() {
        this(new ConvertUtilsBean(), new PropertyUtilsBean());
    }

    /**
     * <p>
     * Constructs an instance using given conversion instances and new {@link PropertyUtilsBean} instance.
     * </p>
     *
     * @param todoRemove use this {@code ConvertUtilsBean} to perform conversions from one object to another
     * @since 1.8.0
     */
    public BeanUtilsBean(final ConvertUtilsBean todoRemove) {
        this(new ConvertUtilsBean(), new PropertyUtilsBean());
    }

    /**
     * <p>
     * Constructs an instance using given property and conversion instances.
     * </p>
     *
     * @param convertUtilsBean  use this {@code ConvertUtilsBean} to perform conversions from one object to another
     * @param propertyUtilsBean use this {@code PropertyUtilsBean} to access properties
     */
    public BeanUtilsBean(final ConvertUtilsBean convertUtilsBean, final PropertyUtilsBean propertyUtilsBean) {
        this.convertUtilsBean = convertUtilsBean;
        this.propertyUtilsBean = propertyUtilsBean;
    }

    /**
     * <p>
     * Clone a bean based on the available property getters and setters, even if the bean class itself does not implement Cloneable.
     * </p>
     *
     * <p>
     * <strong>Note:</strong> this method creates a <strong>shallow</strong> clone. In other words, any objects referred to by the bean are shared with the
     * clone rather than being cloned in turn.
     * </p>
     *
     * @param bean Bean to be cloned
     * @return the cloned bean
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InstantiationException    if a new instance of the bean's class cannot be instantiated
     * @throws InvocationTargetException if the property accessor method throws an exception
     * @throws NoSuchMethodException     if an accessor method for this property cannot be found
     */
    public Object cloneBean(final Object bean) throws IllegalAccessException, InstantiationException, InvocationTargetException, NoSuchMethodException {
        if (LOG.isDebugEnabled()) {
            LOG.debug("Cloning bean: " + bean.getClass().getName());
        }
        Object newBean = null;
        if (bean instanceof DynaBean) {
            newBean = ((DynaBean) bean).getDynaClass().newInstance();
        } else {
            newBean = bean.getClass().newInstance();
        }
        getPropertyUtils().copyProperties(newBean, bean);
        return newBean;
    }

    /**
     * <p>
     * Converts the value to an object of the specified class (if possible).
     * </p>
     *
     * @param <R> the type of the class for the return value.
     * @param value Value to be converted (may be null)
     * @param type  Class of the value to be converted to
     * @return The converted value
     */
    protected <R> Object convert(final Object value, final Class<R> type) {
        return getConvertUtils().convert(value, type);
    }

    /**
     * Performs a type conversion of a property value before it is copied to a target bean. This method delegates to {@link #convert(Object, Class)}, but
     * <strong>null</strong> values are not converted. This causes <strong>null</strong> values to be copied verbatim.
     *
     * @param value the value to be converted and copied
     * @param type  the target type of the conversion
     * @return the converted value
     */
    private Object convertForCopy(final Object value, final Class<?> type) {
        return value != null ? convert(value, type) : value;
    }

    /**
     * <p>
     * Copy property values from the origin bean to the destination bean for all cases where the property names are the same. For each property, a conversion is
     * attempted as necessary. All combinations of standard JavaBeans and DynaBeans as origin and destination are supported. Properties that exist in the origin
     * bean, but do not exist in the destination bean (or are read-only in the destination bean) are silently ignored.
     * </p>
     *
     * <p>
     * If the origin "bean" is actually a {@code Map}, it is assumed to contain String-valued <strong>simple</strong> property names as the keys, pointing at
     * the corresponding property values that will be converted (if necessary) and set in the destination bean. <strong>Note</strong> that this method is
     * intended to perform a "shallow copy" of the properties and so complex properties (for example, nested ones) will not be copied.
     * </p>
     *
     * <p>
     * This method differs from {@code populate()}, which was primarily designed for populating JavaBeans from the map of request parameters retrieved on an
     * HTTP request, is that no scalar-&gt;indexed or indexed-&gt;scalar manipulations are performed. If the origin property is indexed, the destination
     * property must be also.
     * </p>
     *
     * <p>
     * If you know that no type conversions are required, the {@code copyProperties()} method in {@link PropertyUtils} will execute faster than this method.
     * </p>
     *
     * <p>
     * <strong>FIXME</strong> - Indexed and mapped properties that do not have getter and setter methods for the underlying array or Map are not copied by this
     * method.
     * </p>
     *
     * @param dest Destination bean whose properties are modified
     * @param orig Origin bean whose properties are retrieved
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws IllegalArgumentException  if the {@code dest} or {@code orig</code> argument is null or if the <code>dest} property type is different from the
     *                                   source type and the relevant converter has not been registered.
     * @throws InvocationTargetException if the property accessor method throws an exception
     */
    public void copyProperties(final Object dest, final Object orig) throws IllegalAccessException, InvocationTargetException {
        // Validate existence of the specified beans
        Objects.requireNonNull(dest, "dest");
        Objects.requireNonNull(orig, "orig");
        if (LOG.isDebugEnabled()) {
            LOG.debug("BeanUtils.copyProperties(" + dest + ", " + orig + ")");
        }
        // Copy the properties, converting as necessary
        if (orig instanceof DynaBean) {
            final DynaProperty[] origDescriptors = ((DynaBean) orig).getDynaClass().getDynaProperties();
            for (final DynaProperty origDescriptor : origDescriptors) {
                final String name = origDescriptor.getName();
                // Need to check isReadable() for WrapDynaBean
                // (see Jira issue# BEANUTILS-61)
                if (getPropertyUtils().isReadable(orig, name) && getPropertyUtils().isWriteable(dest, name)) {
                    final Object value = ((DynaBean) orig).get(name);
                    copyProperty(dest, name, value);
                }
            }
        } else if (orig instanceof Map) {
            @SuppressWarnings("unchecked")
            final
            // Map properties are always of type <String, Object>
            Map<String, Object> propMap = (Map<String, Object>) orig;
            for (final Map.Entry<String, Object> entry : propMap.entrySet()) {
                final String k = entry.getKey();
                if (getPropertyUtils().isWriteable(dest, k)) {
                    copyProperty(dest, k, entry.getValue());
                }
            }
        } else /* if (orig is a standard JavaBean) */ {
            final PropertyDescriptor[] origDescriptors = getPropertyUtils().getPropertyDescriptors(orig);
            for (final PropertyDescriptor origDescriptor : origDescriptors) {
                final String name = origDescriptor.getName();
                if ("class".equals(name)) {
                    continue; // No point in trying to set an object's class
                }
                if (getPropertyUtils().isReadable(orig, name) && getPropertyUtils().isWriteable(dest, name)) {
                    try {
                        final Object value = getPropertyUtils().getSimpleProperty(orig, name);
                        copyProperty(dest, name, value);
                    } catch (final NoSuchMethodException e) {
                        // Should not happen
                    }
                }
            }
        }
    }

    /**
     * <p>
     * Copy the specified property value to the specified destination bean, performing any type conversion that is required. If the specified bean does not have
     * a property of the specified name, or the property is read only on the destination bean, return without doing anything. If you have custom destination
     * property types, register {@link Converter}s for them by calling the {@code register()} method of {@link ConvertUtils}.
     * </p>
     *
     * <p>
     * <strong>IMPLEMENTATION RESTRICTIONS</strong>:
     * </p>
     * <ul>
     * <li>Does not support destination properties that are indexed, but only an indexed setter (as opposed to an array setter) is available.</li>
     * <li>Does not support destination properties that are mapped, but only a keyed setter (as opposed to a Map setter) is available.</li>
     * <li>The desired property type of a mapped setter cannot be determined (since Maps support any data type), so no conversion will be performed.</li>
     * </ul>
     *
     * @param bean  Bean on which setting is to be performed
     * @param name  Property name (can be nested/indexed/mapped/combo)
     * @param value Value to be set
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     */
    public void copyProperty(final Object bean, String name, Object value) throws IllegalAccessException, InvocationTargetException {
        // Trace logging (if enabled)
        if (LOG.isTraceEnabled()) {
            final StringBuilder sb = new StringBuilder("  copyProperty(");
            sb.append(bean);
            sb.append(", ");
            sb.append(name);
            sb.append(", ");
            if (value == null) {
                sb.append("<NULL>");
            } else if (value instanceof String) {
                sb.append((String) value);
            } else if (value instanceof String[]) {
                final String[] values = (String[]) value;
                sb.append('[');
                for (int i = 0; i < values.length; i++) {
                    if (i > 0) {
                        sb.append(',');
                    }
                    sb.append(values[i]);
                }
                sb.append(']');
            } else {
                sb.append(value.toString());
            }
            sb.append(')');
            LOG.trace(sb.toString());
        }

        // Resolve any nested expression to get the actual target bean
        Object target = bean;
        final Resolver resolver = getPropertyUtils().getResolver();
        while (resolver.hasNested(name)) {
            try {
                target = getPropertyUtils().getProperty(target, resolver.next(name));
                name = resolver.remove(name);
            } catch (final NoSuchMethodException e) {
                return; // Skip this property setter
            }
        }
        if (LOG.isTraceEnabled()) {
            LOG.trace("    Target bean = " + target);
            LOG.trace("    Target name = " + name);
        }

        // Declare local variables we will require
        final String propName = resolver.getProperty(name); // Simple name of target property
        Class<?> type = null; // Java type of target property
        final int index = resolver.getIndex(name); // Indexed subscript value (if any)
        final String key = resolver.getKey(name); // Mapped key value (if any)

        // Calculate the target property type
        if (target instanceof DynaBean) {
            final DynaClass dynaClass = ((DynaBean) target).getDynaClass();
            final DynaProperty dynaProperty = dynaClass.getDynaProperty(propName);
            if (dynaProperty == null) {
                return; // Skip this property setter
            }
            type = dynaPropertyType(dynaProperty, value);
        } else {
            PropertyDescriptor descriptor = null;
            try {
                descriptor = getPropertyUtils().getPropertyDescriptor(target, name);
                if (descriptor == null) {
                    return; // Skip this property setter
                }
            } catch (final NoSuchMethodException e) {
                return; // Skip this property setter
            }
            type = descriptor.getPropertyType();
            if (type == null) {
                // Most likely an indexed setter on a POJB only
                if (LOG.isTraceEnabled()) {
                    LOG.trace("    target type for property '" + propName + "' is null, so skipping the setter");
                }
                return;
            }
        }
        if (LOG.isTraceEnabled()) {
            LOG.trace("    target propName=" + propName + ", type=" + type + ", index=" + index + ", key=" + key);
        }

        // Convert the specified value to the required type and store it
        if (index >= 0) { // Destination must be indexed
            value = convertForCopy(value, type.getComponentType());
            try {
                getPropertyUtils().setIndexedProperty(target, propName, index, value);
            } catch (final NoSuchMethodException e) {
                throw new InvocationTargetException(e, "Cannot set " + propName);
            }
        } else if (key != null) { // Destination must be mapped
            // Maps do not know what the preferred data type is,
            // so perform no conversions at all
            // FIXME - should we create or support a TypedMap?
            try {
                getPropertyUtils().setMappedProperty(target, propName, key, value);
            } catch (final NoSuchMethodException e) {
                throw new InvocationTargetException(e, "Cannot set " + propName);
            }
        } else { // Destination must be simple
            value = convertForCopy(value, type);
            try {
                getPropertyUtils().setSimpleProperty(target, propName, value);
            } catch (final NoSuchMethodException e) {
                throw new InvocationTargetException(e, "Cannot set " + propName);
            }
        }
    }

    /**
     * <p>
     * Return the entire set of properties for which the specified bean provides a read method. This map contains the to {@code String} converted property
     * values for all properties for which a read method is provided (i.e. where the getReadMethod() returns non-null).
     * </p>
     *
     * <p>
     * This map can be fed back to a call to {@code BeanUtils.populate()} to re-constitute the same set of properties, modulo differences for read-only and
     * write-only properties, but only if there are no indexed properties.
     * </p>
     *
     * <p>
     * <strong>Warning:</strong> if any of the bean property implementations contain (directly or indirectly) a call to this method then a stack overflow may
     * result. For example:
     * </p>
     *
     * <pre>
     * <code>
     * class MyBean
     * {
     *    public Map getParameterMap()
     *    {
     *         BeanUtils.describe(this);
     *    }
     * }
     * </code>
     * </pre>
     * <p>
     * will result in an infinite regression when {@code getParametersMap} is called. It is recommended that such methods are given alternative names (for
     * example, {@code parametersMap}).
     * </p>
     *
     * @param bean Bean whose properties are to be extracted
     * @return Map of property descriptors
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     * @throws NoSuchMethodException     if an accessor method for this property cannot be found
     */
    public Map<String, String> describe(final Object bean) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        if (bean == null) {
            // return (Collections.EMPTY_MAP);
            return new java.util.HashMap<>();
        }

        if (LOG.isDebugEnabled()) {
            LOG.debug("Describing bean: " + bean.getClass().getName());
        }

        final Map<String, String> description = new HashMap<>();
        if (bean instanceof DynaBean) {
            final DynaProperty[] descriptors = ((DynaBean) bean).getDynaClass().getDynaProperties();
            for (final DynaProperty descriptor : descriptors) {
                final String name = descriptor.getName();
                description.put(name, getProperty(bean, name));
            }
        } else {
            final PropertyDescriptor[] descriptors = getPropertyUtils().getPropertyDescriptors(bean);
            final Class<?> clazz = bean.getClass();
            for (final PropertyDescriptor descriptor : descriptors) {
                final String name = descriptor.getName();
                if (getPropertyUtils().getReadMethod(clazz, descriptor) != null) {
                    description.put(name, getProperty(bean, name));
                }
            }
        }
        return description;
    }

    /**
     * Gets the value of the specified array property of the specified bean, as a String array.
     *
     * @param bean Bean whose property is to be extracted
     * @param name Name of the property to be extracted
     * @return The array property value
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     * @throws NoSuchMethodException     if an accessor method for this property cannot be found
     */
    public String[] getArrayProperty(final Object bean, final String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        final Object value = getPropertyUtils().getProperty(bean, name);
        if (value == null) {
            return null;
        }
        if (value instanceof Collection) {
            return ((Collection<?>) value).stream().map(item -> item != null ? getConvertUtils().convert(item) : null).toArray(String[]::new);
        }
        if (!value.getClass().isArray()) {
            final String[] results = new String[1];
            results[0] = getConvertUtils().convert(value);
            return results;
        }
        final int n = Array.getLength(value);
        final String[] results = new String[n];
        for (int i = 0; i < n; i++) {
            final Object item = Array.get(value, i);
            if (item == null) {
                results[i] = null;
            } else {
                // convert to string using convert utils
                results[i] = getConvertUtils().convert(item);
            }
        }
        return results;
    }

    /**
     * Gets the {@code ConvertUtilsBean} instance used to perform the conversions.
     *
     * @return The ConvertUtils bean instance
     */
    public ConvertUtilsBean getConvertUtils() {
        return convertUtilsBean;
    }

    /**
     * Gets the value of the specified indexed property of the specified bean, as a String. The zero-relative index of the required value must be included (in
     * square brackets) as a suffix to the property name, or {@code IllegalArgumentException} will be thrown.
     *
     * @param bean Bean whose property is to be extracted
     * @param name {@code propertyname[index]} of the property value to be extracted
     * @return The indexed property's value, converted to a String
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     * @throws NoSuchMethodException     if an accessor method for this property cannot be found
     */
    public String getIndexedProperty(final Object bean, final String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        final Object value = getPropertyUtils().getIndexedProperty(bean, name);
        return getConvertUtils().convert(value);
    }

    /**
     * Gets the value of the specified indexed property of the specified bean, as a String. The index is specified as a method parameter and must *not* be
     * included in the property name expression
     *
     * @param bean  Bean whose property is to be extracted
     * @param name  Simple property name of the property value to be extracted
     * @param index Index of the property value to be extracted
     * @return The indexed property's value, converted to a String
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     * @throws NoSuchMethodException     if an accessor method for this property cannot be found
     */
    public String getIndexedProperty(final Object bean, final String name, final int index)
            throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        final Object value = getPropertyUtils().getIndexedProperty(bean, name, index);
        return getConvertUtils().convert(value);
    }

    /**
     * Gets the value of the specified indexed property of the specified bean, as a String. The String-valued key of the required value must be included (in
     * parentheses) as a suffix to the property name, or {@code IllegalArgumentException} will be thrown.
     *
     * @param bean Bean whose property is to be extracted
     * @param name {@code propertyname(index)} of the property value to be extracted
     * @return The mapped property's value, converted to a String
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     * @throws NoSuchMethodException     if an accessor method for this property cannot be found
     */
    public String getMappedProperty(final Object bean, final String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        final Object value = getPropertyUtils().getMappedProperty(bean, name);
        return getConvertUtils().convert(value);
    }

    /**
     * Gets the value of the specified mapped property of the specified bean, as a String. The key is specified as a method parameter and must *not* be included
     * in the property name expression
     *
     * @param bean Bean whose property is to be extracted
     * @param name Simple property name of the property value to be extracted
     * @param key  Lookup key of the property value to be extracted
     * @return The mapped property's value, converted to a String
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     * @throws NoSuchMethodException     if an accessor method for this property cannot be found
     */
    public String getMappedProperty(final Object bean, final String name, final String key)
            throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        final Object value = getPropertyUtils().getMappedProperty(bean, name, key);
        return getConvertUtils().convert(value);
    }

    /**
     * Gets the value of the (possibly nested) property of the specified name, for the specified bean, as a String.
     *
     * @param bean Bean whose property is to be extracted
     * @param name Possibly nested name of the property to be extracted
     * @return The nested property's value, converted to a String
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws IllegalArgumentException  if a nested reference to a property returns null
     * @throws InvocationTargetException if the property accessor method throws an exception
     * @throws NoSuchMethodException     if an accessor method for this property cannot be found
     */
    public String getNestedProperty(final Object bean, final String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        final Object value = getPropertyUtils().getNestedProperty(bean, name);
        return getConvertUtils().convert(value);
    }

    /**
     * Gets the value of the specified property of the specified bean, no matter which property reference format is used, as a String.
     *
     * @param bean Bean whose property is to be extracted
     * @param name Possibly indexed and/or nested name of the property to be extracted
     * @return The property's value, converted to a String
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     * @throws NoSuchMethodException     if an accessor method for this property cannot be found
     */
    public String getProperty(final Object bean, final String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        return getNestedProperty(bean, name);
    }

    /**
     * Gets the {@code PropertyUtilsBean} instance used to access properties.
     *
     * @return The ConvertUtils bean instance
     */
    public PropertyUtilsBean getPropertyUtils() {
        return propertyUtilsBean;
    }

    /**
     * Gets the value of the specified simple property of the specified bean, converted to a String.
     *
     * @param bean Bean whose property is to be extracted
     * @param name Name of the property to be extracted
     * @return The property's value, converted to a String
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     * @throws NoSuchMethodException     if an accessor method for this property cannot be found
     */
    public String getSimpleProperty(final Object bean, final String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        final Object value = getPropertyUtils().getSimpleProperty(bean, name);
        return getConvertUtils().convert(value);
    }

    /**
     * <p>
     * Populate the JavaBeans properties of the specified bean, based on the specified name/value pairs. This method uses Java reflection APIs to identify
     * corresponding "property setter" method names, and deals with setter arguments of type {@code String</code>, <code>boolean}, {@code int}, {@code long},
     * {@code float}, and {@code double}. In addition, array setters for these types (or the corresponding primitive types) can also be identified.
     * </p>
     *
     * <p>
     * The particular setter method to be called for each property is determined using the usual JavaBeans introspection mechanisms. Thus, you may identify
     * custom setter methods using a BeanInfo class that is associated with the class of the bean itself. If no such BeanInfo class is available, the standard
     * method name conversion ("set" plus the capitalized name of the property in question) is used.
     * </p>
     *
     * <p>
     * <strong>NOTE</strong>: It is contrary to the JavaBeans Specification to have more than one setter method (with different argument signatures) for the
     * same property.
     * </p>
     *
     * <p>
     * <strong>WARNING</strong> - The logic of this method is customized for extracting String-based request parameters from an HTTP request. It is probably not
     * what you want for general property copying with type conversion. For that purpose, check out the {@code copyProperties()} method instead.
     * </p>
     *
     * @param bean       JavaBean whose properties are being populated
     * @param properties Map keyed by property name, with the corresponding (String or String[]) value(s) to be set
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     */
    public void populate(final Object bean, final Map<String, ? extends Object> properties) throws IllegalAccessException, InvocationTargetException {
        // Do nothing unless both arguments have been specified
        if (bean == null || properties == null) {
            return;
        }
        if (LOG.isDebugEnabled()) {
            LOG.debug("BeanUtils.populate(" + bean + ", " + properties + ")");
        }

        // Loop through the property name/value pairs to be set
        for (final Map.Entry<String, ? extends Object> entry : properties.entrySet()) {
            // Identify the property name and value(s) to be assigned
            final String name = entry.getKey();
            if (name == null) {
                continue;
            }

            // Perform the assignment for this property
            setProperty(bean, name, entry.getValue());
        }
    }

    /**
     * <p>
     * Set the specified property value, performing type conversions as required to conform to the type of the destination property.
     * </p>
     *
     * <p>
     * If the property is read only then the method returns without throwing an exception.
     * </p>
     *
     * <p>
     * If {@code null} is passed into a property expecting a primitive value, then this will be converted as if it were a {@code null} string.
     * </p>
     *
     * <p>
     * <strong>WARNING</strong> - The logic of this method is customized to meet the needs of {@code populate()}, and is probably not what you want for general
     * property copying with type conversion. For that purpose, check out the {@code copyProperty()} method instead.
     * </p>
     *
     * <p>
     * <strong>WARNING</strong> - PLEASE do not modify the behavior of this method without consulting with the Struts developer community. There are some
     * subtleties to its functionality that are not documented in the Javadoc description above, yet are vital to the way that Struts utilizes this method.
     * </p>
     *
     * @param bean  Bean on which setting is to be performed
     * @param name  Property name (can be nested/indexed/mapped/combo)
     * @param value Value to be set
     * @throws IllegalAccessException    if the caller does not have access to the property accessor method
     * @throws InvocationTargetException if the property accessor method throws an exception
     */
    public void setProperty(final Object bean, String name, final Object value) throws IllegalAccessException, InvocationTargetException {
        // Trace logging (if enabled)
        if (LOG.isTraceEnabled()) {
            final StringBuilder sb = new StringBuilder("  setProperty(");
            sb.append(bean);
            sb.append(", ");
            sb.append(name);
            sb.append(", ");
            if (value == null) {
                sb.append("<NULL>");
            } else if (value instanceof String) {
                sb.append((String) value);
            } else if (value instanceof String[]) {
                final String[] values = (String[]) value;
                sb.append('[');
                for (int i = 0; i < values.length; i++) {
                    if (i > 0) {
                        sb.append(',');
                    }
                    sb.append(values[i]);
                }
                sb.append(']');
            } else {
                sb.append(value.toString());
            }
            sb.append(')');
            LOG.trace(sb.toString());
        }

        // Resolve any nested expression to get the actual target bean
        Object target = bean;
        final Resolver resolver = getPropertyUtils().getResolver();
        while (resolver.hasNested(name)) {
            try {
                target = getPropertyUtils().getProperty(target, resolver.next(name));
                if (target == null) { // the value of a nested property is null
                    return;
                }
                name = resolver.remove(name);
            } catch (final NoSuchMethodException e) {
                return; // Skip this property setter
            }
        }
        if (LOG.isTraceEnabled()) {
            LOG.trace("    Target bean = " + target);
            LOG.trace("    Target name = " + name);
        }

        // Declare local variables we will require
        final String propName = resolver.getProperty(name); // Simple name of target property
        Class<?> type = null; // Java type of target property
        final int index = resolver.getIndex(name); // Indexed subscript value (if any)
        final String key = resolver.getKey(name); // Mapped key value (if any)

        // Calculate the property type
        if (target instanceof DynaBean) {
            final DynaClass dynaClass = ((DynaBean) target).getDynaClass();
            final DynaProperty dynaProperty = dynaClass.getDynaProperty(propName);
            if (dynaProperty == null) {
                return; // Skip this property setter
            }
            type = dynaPropertyType(dynaProperty, value);
            if (index >= 0 && List.class.isAssignableFrom(type)) {
                type = Object.class;
            }
        } else if (target instanceof Map) {
            type = Object.class;
        } else if (target != null && target.getClass().isArray() && index >= 0) {
            type = Array.get(target, index).getClass();
        } else {
            PropertyDescriptor descriptor = null;
            try {
                descriptor = getPropertyUtils().getPropertyDescriptor(target, name);
                if (descriptor == null) {
                    return; // Skip this property setter
                }
            } catch (final NoSuchMethodException e) {
                return; // Skip this property setter
            }
            if (descriptor instanceof MappedPropertyDescriptor) {
                if (((MappedPropertyDescriptor) descriptor).getMappedWriteMethod() == null) {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Skipping read-only property");
                    }
                    return; // Read-only, skip this property setter
                }
                type = ((MappedPropertyDescriptor) descriptor).getMappedPropertyType();
            } else if (index >= 0 && descriptor instanceof IndexedPropertyDescriptor) {
                if (((IndexedPropertyDescriptor) descriptor).getIndexedWriteMethod() == null) {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Skipping read-only property");
                    }
                    return; // Read-only, skip this property setter
                }
                type = ((IndexedPropertyDescriptor) descriptor).getIndexedPropertyType();
            } else if (index >= 0 && List.class.isAssignableFrom(descriptor.getPropertyType())) {
                type = Object.class;
            } else if (key != null) {
                if (descriptor.getReadMethod() == null) {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Skipping read-only property");
                    }
                    return; // Read-only, skip this property setter
                }
                type = value == null ? Object.class : value.getClass();
            } else {
                if (descriptor.getWriteMethod() == null) {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Skipping read-only property");
                    }
                    return; // Read-only, skip this property setter
                }
                type = descriptor.getPropertyType();
            }
        }

        // Convert the specified value to the required type
        Object newValue = null;
        if (type.isArray() && index < 0) { // Scalar value into array
            if (value == null) {
                final String[] values = new String[1];
                values[0] = null;
                newValue = getConvertUtils().convert(values, type);
            } else if (value instanceof String) {
                newValue = getConvertUtils().convert(value, type);
            } else if (value instanceof String[]) {
                newValue = getConvertUtils().convert((String[]) value, type);
            } else {
                newValue = convert(value, type);
            }
        } else if (type.isArray()) { // Indexed value into array
            if (value instanceof String || value == null) {
                newValue = getConvertUtils().convert((String) value, type.getComponentType());
            } else if (value instanceof String[]) {
                newValue = getConvertUtils().convert(((String[]) value)[0], type.getComponentType());
            } else {
                newValue = convert(value, type.getComponentType());
            }
        } else if (value instanceof String) {
            newValue = getConvertUtils().convert((String) value, type);
        } else if (value instanceof String[]) {
            newValue = getConvertUtils().convert(((String[]) value)[0], type);
        } else {
            newValue = convert(value, type);
        }

        // Invoke the setter method
        try {
            getPropertyUtils().setProperty(target, name, newValue);
        } catch (final NoSuchMethodException e) {
            throw new InvocationTargetException(e, "Cannot set " + propName);
        }
    }
}