org.springframework.webflow.action.FormObjectAccessor Maven / Gradle / Ivy
/*
* Copyright 2002-2006 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.webflow.action;
import org.springframework.validation.BindException;
import org.springframework.validation.Errors;
import org.springframework.webflow.execution.RequestContext;
import org.springframework.webflow.execution.ScopeType;
/**
* Convenience helper that encapsulates logic on how to retrieve and expose form
* objects and associated errors to and from a flow execution request context.
*
* Note: The form object available under the well known attribute name
* {@link #CURRENT_FORM_OBJECT_ATTRIBUTE} will be the last ("current") form
* object set in the request context. The same is true for the associated errors
* object. This implies that special care should be taken when accessing the
* form object using this alias if there are multiple form objects available in
* the flow execution request context!
*
* @see org.springframework.webflow.execution.RequestContext
* @see org.springframework.validation.Errors
*
* @author Keith Donald
* @author Erwin Vervaet
*/
public class FormObjectAccessor {
/**
* The form object instance is aliased under this attribute name in the flow
* context by the default form setup and bind and validate actions.
*
* Note that if you would have multiple form objects in the request context,
* the last one that was used would be available using this alias!
*
* We need to keep track of the 'current form object' using this attribute
* to be able to deal with the limitations of some clients that can only
* deal with a single form backing object, e.g. Struts when using the Struts
* FlowAction.
*/
private static final String CURRENT_FORM_OBJECT_ATTRIBUTE = "currentFormObject";
/**
* The errors prefix.
*/
//use deprecated API to remain compatible with Spring 1.2.x
private static final String ERRORS_PREFIX = BindException.ERROR_KEY_PREFIX;
/**
* The wrapped request context.
*/
private RequestContext context;
/**
* Creates a form object accessor that wraps the given context.
* @param context the flow execution request context
*/
public FormObjectAccessor(RequestContext context) {
this.context = context;
}
/**
* Returns the current form object name.
* @return the current form object name
*/
public static String getCurrentFormObjectName() {
return CURRENT_FORM_OBJECT_ATTRIBUTE;
}
/**
* Returns the current form object errors attribute name.
* @return the current form object errors attribute name
*/
public static String getCurrentFormErrorsName() {
return ERRORS_PREFIX + getCurrentFormObjectName();
}
/**
* Gets the form object from the context, using the well-known attribute
* name {@link #CURRENT_FORM_OBJECT_ATTRIBUTE}. Will try all scopes.
* @return the form object, or null if not found
*/
public Object getCurrentFormObject() {
Object formObject = getCurrentFormObject(ScopeType.REQUEST);
if (formObject != null) {
return formObject;
}
formObject = getCurrentFormObject(ScopeType.FLASH);
if (formObject != null) {
return formObject;
}
formObject = getCurrentFormObject(ScopeType.FLOW);
if (formObject != null) {
return formObject;
}
return getCurrentFormObject(ScopeType.CONVERSATION);
}
/**
* Gets the form object from the context, using the well-known attribute
* name {@link #CURRENT_FORM_OBJECT_ATTRIBUTE}.
* @param scopeType the scope to obtain the form object from
* @return the form object, or null if not found
*/
public Object getCurrentFormObject(ScopeType scopeType) {
return getFormObject(getCurrentFormObjectName(), scopeType);
}
/**
* Expose given form object using the well known alias
* {@link #CURRENT_FORM_OBJECT_ATTRIBUTE} in the specified scope.
* @param formObject the form object
* @param scopeType the scope in which to expose the form object
*/
public void setCurrentFormObject(Object formObject, ScopeType scopeType) {
//don't call setFormObject since that would cause infinite recursion!
scopeType.getScope(context).put(getCurrentFormObjectName(), formObject);
}
/**
* Gets the form object from the context, using the specified name.
* @param formObjectName the name of the form object in the context
* @param scopeType the scope to obtain the form object from
* @return the form object, or null if not found
*/
public Object getFormObject(String formObjectName, ScopeType scopeType) {
return scopeType.getScope(context).get(formObjectName);
}
/**
* Gets the form object from the context, using the specified name.
* @param formObjectName the name of the form in the context
* @param formObjectClass the class of the form object, which will be
* verified
* @param scopeType the scope to obtain the form object from
* @return the form object, or null if not found
*/
public Object getFormObject(String formObjectName, Class formObjectClass, ScopeType scopeType) {
return scopeType.getScope(context).get(formObjectName, formObjectClass);
}
/**
* Expose given form object using given name in specified scope. Given
* object will become the current form object.
* @param formObject the form object
* @param formObjectName the name of the form object
* @param scopeType the scope in which to expose the form object
*/
public void putFormObject(Object formObject, String formObjectName, ScopeType scopeType) {
scopeType.getScope(context).put(formObjectName, formObject);
setCurrentFormObject(formObject, scopeType);
}
/**
* Gets the form object Errors tracker from the context,
* using the form object name {@link #CURRENT_FORM_OBJECT_ATTRIBUTE}. This
* method will search all scopes.
* @return the form object Errors tracker, or null if not found
*/
public Errors getCurrentFormErrors() {
Errors errors = getCurrentFormErrors(ScopeType.REQUEST);
if (errors != null) {
return errors;
}
errors = getCurrentFormErrors(ScopeType.FLASH);
if (errors != null) {
return errors;
}
errors = getCurrentFormErrors(ScopeType.FLOW);
if (errors != null) {
return errors;
}
return getCurrentFormErrors(ScopeType.CONVERSATION);
}
/**
* Gets the form object Errors tracker from the context,
* using the form object name {@link #CURRENT_FORM_OBJECT_ATTRIBUTE}.
* @param scopeType the scope to obtain the errors from
* @return the form object Errors tracker, or null if not found
*/
public Errors getCurrentFormErrors(ScopeType scopeType) {
return getFormErrors(getCurrentFormObjectName(), scopeType);
}
/**
* Expose given errors instance using the well known alias
* {@link #CURRENT_FORM_OBJECT_ATTRIBUTE} in the specified scope.
* @param errors the errors instance
* @param scopeType the scope in which to expose the errors instance
*/
public void setCurrentFormErrors(Errors errors, ScopeType scopeType) {
scopeType.getScope(context).put(getCurrentFormErrorsName(), errors);
}
/**
* Gets the form object Errors tracker from the context,
* using the specified form object name.
* @param formObjectName the name of the Errors object, which will be
* prefixed with {@link BindException#ERROR_KEY_PREFIX}
* @param scopeType the scope to obtain the errors from
* @return the form object errors instance, or null if not found
*/
public Errors getFormErrors(String formObjectName, ScopeType scopeType) {
return (Errors)scopeType.getScope(context).get(ERRORS_PREFIX + formObjectName, Errors.class);
}
/**
* Expose given errors instance in the specified scope. Given errors
* instance will become the current form errors instance.
* @param errors the errors object
* @param scopeType the scope to expose the errors in
*/
public void putFormErrors(Errors errors, ScopeType scopeType) {
scopeType.getScope(context).put(ERRORS_PREFIX + errors.getObjectName(), errors);
setCurrentFormErrors(errors, scopeType);
}
}