/*
 * Copyright 2002-2018 the original author or authors.
 *
 * 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.springframework.validation;

import java.io.Serializable;

import org.springframework.beans.BeanWrapper;
import org.springframework.beans.ConfigurablePropertyAccessor;
import org.springframework.beans.PropertyAccessorFactory;
import org.springframework.lang.Nullable;

Default implementation of the Errors and BindingResult interfaces, for the registration and evaluation of binding errors on JavaBean objects. 
Performs standard JavaBean property access, also supporting nested properties. Normally, application code will work with the Errors interface or the BindingResult interface. A DataBinder returns its BindingResult via DataBinder.getBindingResult(). 
Author:
Juergen Hoeller
See Also:
DataBinder.getBindingResult()
DataBinder.initBeanPropertyAccess()
DirectFieldBindingResult
Since:
2.0/**
 * Default implementation of the {@link Errors} and {@link BindingResult}
 * interfaces, for the registration and evaluation of binding errors on
 * JavaBean objects.
 *
 * <p>Performs standard JavaBean property access, also supporting nested
 * properties. Normally, application code will work with the
 * {@code Errors} interface or the {@code BindingResult} interface.
 * A {@link DataBinder} returns its {@code BindingResult} via
 * {@link DataBinder#getBindingResult()}.
 *
 * @author Juergen Hoeller
 * @since 2.0
 * @see DataBinder#getBindingResult()
 * @see DataBinder#initBeanPropertyAccess()
 * @see DirectFieldBindingResult
 */
@SuppressWarnings("serial")
public class BeanPropertyBindingResult extends AbstractPropertyBindingResult implements Serializable {

	@Nullable
	private final Object target;

	private final boolean autoGrowNestedPaths;

	private final int autoGrowCollectionLimit;

	@Nullable
	private transient BeanWrapper beanWrapper;


	
Creates a new instance of the BeanPropertyBindingResult class. 
Params:
target – the target bean to bind onto
objectName – the name of the target object/**
	 * Creates a new instance of the {@link BeanPropertyBindingResult} class.
	 * @param target the target bean to bind onto
	 * @param objectName the name of the target object
	 */
	public BeanPropertyBindingResult(@Nullable Object target, String objectName) {
		this(target, objectName, true, Integer.MAX_VALUE);
	}

	
Creates a new instance of the BeanPropertyBindingResult class. 
Params:
target – the target bean to bind onto
objectName – the name of the target object
autoGrowNestedPaths – whether to "auto-grow" a nested path that contains a null value
autoGrowCollectionLimit – the limit for array and collection auto-growing/**
	 * Creates a new instance of the {@link BeanPropertyBindingResult} class.
	 * @param target the target bean to bind onto
	 * @param objectName the name of the target object
	 * @param autoGrowNestedPaths whether to "auto-grow" a nested path that contains a null value
	 * @param autoGrowCollectionLimit the limit for array and collection auto-growing
	 */
	public BeanPropertyBindingResult(@Nullable Object target, String objectName,
			boolean autoGrowNestedPaths, int autoGrowCollectionLimit) {

		super(objectName);
		this.target = target;
		this.autoGrowNestedPaths = autoGrowNestedPaths;
		this.autoGrowCollectionLimit = autoGrowCollectionLimit;
	}


	@Override
	@Nullable
	public final Object getTarget() {
		return this.target;
	}

	
Returns the BeanWrapper that this instance uses. Creates a new one if none existed before. 
See Also:
createBeanWrapper()/**
	 * Returns the {@link BeanWrapper} that this instance uses.
	 * Creates a new one if none existed before.
	 * @see #createBeanWrapper()
	 */
	@Override
	public final ConfigurablePropertyAccessor getPropertyAccessor() {
		if (this.beanWrapper == null) {
			this.beanWrapper = createBeanWrapper();
			this.beanWrapper.setExtractOldValueForEditor(true);
			this.beanWrapper.setAutoGrowNestedPaths(this.autoGrowNestedPaths);
			this.beanWrapper.setAutoGrowCollectionLimit(this.autoGrowCollectionLimit);
		}
		return this.beanWrapper;
	}

	
Create a new BeanWrapper for the underlying target object. 
See Also:
getTarget()/**
	 * Create a new {@link BeanWrapper} for the underlying target object.
	 * @see #getTarget()
	 */
	protected BeanWrapper createBeanWrapper() {
		if (this.target == null) {
			throw new IllegalStateException("Cannot access properties on null bean instance '" + getObjectName() + "'");
		}
		return PropertyAccessorFactory.forBeanPropertyAccess(this.target);
	}

}