databinder.java

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/*
 * Copyright 2002-2007 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.beans.PropertyEditor;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.ConfigurablePropertyAccessor;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.PropertyAccessException;
import org.springframework.beans.PropertyAccessorUtils;
import org.springframework.beans.PropertyBatchUpdateException;
import org.springframework.beans.PropertyEditorRegistry;
import org.springframework.beans.PropertyValue;
import org.springframework.beans.PropertyValues;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.PatternMatchUtils;
import org.springframework.util.StringUtils;

/**
 * Binder that allows for setting property values onto a target object,
 * including support for validation and binding result analysis.
 * The binding process can be customized through specifying allowed fields,
 * required fields, custom editors, etc.
 *
 * <p>Note that there are potential security implications in failing to set an array
 * of allowed fields. In the case of HTTP form POST data for example, malicious clients
 * can attempt to subvert an application by supplying values for fields or properties
 * that do not exist on the form. In some cases this could lead to illegal data being
 * set on command objects <i>or their nested objects</i>. For this reason, it is
 * <b>highly recommended to specify the {@link #setAllowedFields allowedFields} property</b>
 * on the DataBinder.
 *
 * <p>The binding results can be examined via the {@link BindingResult} interface,
 * extending the {@link Errors} interface: see the {@link #getBindingResult()} method.
 * Missing fields and property access exceptions will be converted to {@link FieldError FieldErrors},
 * collected in the Errors instance, using the following error codes:
 *
 * <ul>
 * <li>Missing field error: "required"
 * <li>Type mismatch error: "typeMismatch"
 * <li>Method invocation error: "methodInvocation"
 * </ul>
 *
 * <p>By default, binding errors get resolved through the {@link BindingErrorProcessor}
 * strategy, processing for missing fields and property access exceptions: see the
 * {@link #setBindingErrorProcessor} method. You can override the default strategy
 * if needed, for example to generate different error codes.
 *
 * <p>Custom validation errors can be added afterwards. You will typically want to resolve
 * such error codes into proper user-visible error messages; this can be achieved through
 * resolving each error via a {@link org.springframework.context.MessageSource}, which is
 * able to resolve an {@link ObjectError}/{@link FieldError} through its
 * {@link org.springframework.context.MessageSource#getMessage(org.springframework.context.MessageSourceResolvable, java.util.Locale)}
 * method. The list of message codes can be customized through the {@link MessageCodesResolver}
 * strategy: see the {@link #setMessageCodesResolver} method. {@link DefaultMessageCodesResolver}'s
 * javadoc states details on the default resolution rules.
 *
 * <p>This generic data binder can be used in any kind of environment.
 * It is typically used by Spring web MVC controllers, via the web-specific
 * subclasses {@link org.springframework.web.bind.ServletRequestDataBinder}
 * and {@link org.springframework.web.portlet.bind.PortletRequestDataBinder}.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Rob Harrop
 * @see #setAllowedFields
 * @see #setRequiredFields
 * @see #registerCustomEditor
 * @see #setMessageCodesResolver
 * @see #setBindingErrorProcessor
 * @see #bind
 * @see #getBindingResult
 * @see DefaultMessageCodesResolver
 * @see DefaultBindingErrorProcessor
 * @see org.springframework.context.MessageSource
 * @see org.springframework.web.bind.ServletRequestDataBinder
 */
public class DataBinder implements PropertyEditorRegistry {

	/** Default object name used for binding: "target" */
	public static final String DEFAULT_OBJECT_NAME = "target";


	/**
	 * We'll create a lot of DataBinder instances: Let's use a static logger.
	 */
	protected static final Log logger = LogFactory.getLog(DataBinder.class);

	private final Object target;

	private final String objectName;

	private AbstractPropertyBindingResult bindingResult;

	private BindException bindException;

	private boolean ignoreUnknownFields = true;

	private boolean ignoreInvalidFields = false;

	private String[] allowedFields;

	private String[] disallowedFields;

	private String[] requiredFields;

	private BindingErrorProcessor bindingErrorProcessor = new DefaultBindingErrorProcessor();


	/**
	 * Create a new DataBinder instance, with default object name.
	 * @param target target object to bind onto
	 * @see #DEFAULT_OBJECT_NAME
	 */
	public DataBinder(Object target) {
		this(target, DEFAULT_OBJECT_NAME);
	}

	/**
	 * Create a new DataBinder instance.
	 * @param target target object to bind onto
	 * @param objectName name of the target object
	 */
	public DataBinder(Object target, String objectName) {
		Assert.notNull(target, "Target must not be null");
		this.target = target;
		this.objectName = objectName;
	}


	/**
	 * Return the wrapped target object.
	 */
	public Object getTarget() {
		return this.target;
	}

	/**
	 * Return the name of the bound object.
	 */
	public String getObjectName() {
		return this.objectName;
	}

	/**
	 * Initialize standard JavaBean property access for this DataBinder.
	 * <p>This is the default; an explicit call just leads to eager initialization.
	 * @see #initDirectFieldAccess()
	 */
	public void initBeanPropertyAccess() {
		Assert.isNull(this.bindingResult,
				"DataBinder is already initialized - call initBeanPropertyAccess before any other configuration methods");
		this.bindingResult = new BeanPropertyBindingResult(getTarget(), getObjectName());
	}

	/**
	 * Initialize direct field access for this DataBinder,
	 * as alternative to the default bean property access.
	 * @see #initBeanPropertyAccess()
	 */
	public void initDirectFieldAccess() {
		Assert.isNull(this.bindingResult,
				"DataBinder is already initialized - call initDirectFieldAccess before any other configuration methods");
		this.bindingResult = new DirectFieldBindingResult(getTarget(), getObjectName());
	}

	/**
	 * Return the internal BindingResult held by this DataBinder,
	 * as AbstractPropertyBindingResult.
	 */
	protected AbstractPropertyBindingResult getInternalBindingResult() {
		if (this.bindingResult == null) {
			initBeanPropertyAccess();
		}
		return this.bindingResult;
	}

	/**
	 * Return the underlying PropertyAccessor of this binder's BindingResult.
	 * To be used by binder subclasses that need property checks.
	 */
	protected ConfigurablePropertyAccessor getPropertyAccessor() {
		return getInternalBindingResult().getPropertyAccessor();
	}

	/**
	 * Return the BindingResult instance created by this DataBinder.
	 * This allows for convenient access to the binding results after
	 * a bind operation.
	 * @return the BindingResult instance, to be treated as BindingResult
	 * or as Errors instance (Errors is a super-interface of BindingResult)
	 * @see Errors
	 * @see #bind
	 */
	public BindingResult getBindingResult() {
		return getInternalBindingResult();
	}

	/**
	 * Return the Errors instance for this data binder.
	 * @return the Errors instance, to be treated as Errors or as BindException
	 * @deprecated in favor of {@link #getBindingResult()}.
	 * Use the {@link BindException#BindException(BindingResult)} constructor
	 * to create a BindException instance if still needed.
	 * @see #getBindingResult()
	 */
	public BindException getErrors() {
		if (this.bindException == null) {
			this.bindException = new BindException(getBindingResult());
		}
		return this.bindException;
	}


	/**
	 * Set whether to ignore unknown fields, that is, whether to ignore bind
	 * parameters that do not have corresponding fields in the target object.
	 * <p>Default is "true". Turn this off to enforce that all bind parameters
	 * must have a matching field in the target object.
	 * <p>Note that this setting only applies to <i>binding</i> operations
	 * on this DataBinder, not to <i>retrieving</i> values via its
	 * {@link #getBindingResult() BindingResult}.
	 * @see #bind
	 */
	public void setIgnoreUnknownFields(boolean ignoreUnknownFields) {
		this.ignoreUnknownFields = ignoreUnknownFields;
	}

	/**
	 * Return whether to ignore unknown fields when binding.
	 */
	public boolean isIgnoreUnknownFields() {
		return this.ignoreUnknownFields;
	}

	/**
	 * Set whether to ignore invalid fields, that is, whether to ignore bind
	 * parameters that have corresponding fields in the target object which are
	 * not accessible (for example because of null values in the nested path).
	 * <p>Default is "false". Turn this on to ignore bind parameters for
	 * nested objects in non-existing parts of the target object graph.
	 * <p>Note that this setting only applies to <i>binding</i> operations
	 * on this DataBinder, not to <i>retrieving</i> values via its
	 * {@link #getBindingResult() BindingResult}.
	 * @see #bind
	 */
	public void setIgnoreInvalidFields(boolean ignoreInvalidFields) {
		this.ignoreInvalidFields = ignoreInvalidFields;
	}

	/**
	 * Return whether to ignore invalid fields when binding.
	 */
	public boolean isIgnoreInvalidFields() {
		return this.ignoreInvalidFields;
	}

	/**
	 * Register fields that should be allowed for binding. Default is all
	 * fields. Restrict this for example to avoid unwanted modifications