com.opensymphony.xwork2.interceptor
Class ParametersInterceptor

java.lang.Object
  com.opensymphony.xwork2.interceptor.AbstractInterceptor
      com.opensymphony.xwork2.interceptor.MethodFilterInterceptor
          com.opensymphony.xwork2.interceptor.ParametersInterceptor

All Implemented Interfaces:

Interceptor, Serializable

public class ParametersInterceptor
extends MethodFilterInterceptor

This interceptor sets all parameters on the value stack.

This interceptor gets all parameters from ActionContext.getParameters() and sets them on the value stack by calling ValueStack.setValue(String, Object), typically resulting in the values submitted in a form request being applied to an action in the value stack. Note that the parameter map must contain a String key and often containers a String[] for the value.

The interceptor takes one parameter named 'ordered'. When set to true action properties are guaranteed to be set top-down which means that top action's properties are set first. Then it's subcomponents properties are set. The reason for this order is to enable a 'factory' pattern. For example, let's assume that one has an action that contains a property named 'modelClass' that allows to choose what is the underlying implementation of model. By assuring that modelClass property is set before any model properties are set, it's possible to choose model implementation during action.setModelClass() call. Similiarily it's possible to use action.setPrimaryKey() property set call to actually load the model class from persistent storage. Without any assumption on parameter order you have to use patterns like 'Preparable'.

Because parameter names are effectively OGNL statements, it is important that security be taken in to account. This interceptor will not apply any values in the parameters map if the expression contains an assignment (=), multiple expressions (,), or references any objects in the context (#). This is all done in the acceptableName(String) method. In addition to this method, if the action being invoked implements the ParameterNameAware interface, the action will be consulted to determine if the parameter should be set.

In addition to these restrictions, a flag (ReflectionContextState.DENY_METHOD_EXECUTION) is set such that no methods are allowed to be invoked. That means that any expression such as person.doSomething() or person.getName() will be explicitely forbidden. This is needed to make sure that your application is not exposed to attacks by malicious users.

While this interceptor is being invoked, a flag (ReflectionContextState.CREATE_NULL_OBJECTS) is turned on to ensure that any null reference is automatically created - if possible. See the type conversion documentation and the InstantiatingNullHandler javadocs for more information.

Finally, a third flag (XWorkConverter.REPORT_CONVERSION_ERRORS) is set that indicates any errors when converting the the values to their final data type (String[] -> int) an unrecoverable error occured. With this flag set, the type conversion errors will be reported in the action context. See the type conversion documentation and the XWorkConverter javadocs for more information.

If you are looking for detailed logging information about your parameters, turn on DEBUG level logging for this interceptor. A detailed log of all the parameter keys and values will be reported.

Note: Since XWork 2.0.2, this interceptor extends MethodFilterInterceptor, therefore being able to deal with excludeMethods / includeMethods parameters. See [Workflow Interceptor] (class DefaultWorkflowInterceptor) for documentation and examples on how to use this feature.

Interceptor parameters:

• ordered - set to true if you want the top-down property setter behaviour

Extending the interceptor:

The best way to add behavior to this interceptor is to utilize the ParameterNameAware interface in your actions. However, if you wish to apply a global rule that isn't implemented in your action, then you could extend this interceptor and override the acceptableName(String) method.

Example code:

 
 <action name="someAction" class="com.examples.SomeAction">
     <interceptor-ref name="params"/>
     <result name="success">good_result.ftl</result>
 </action>
 
 

Author:

Patrick Lightbody

See Also:

Serialized Form

Field Summary

Fields inherited from class com.opensymphony.xwork2.interceptor.MethodFilterInterceptor

excludeMethods, includeMethods, log

Constructor Summary

ParametersInterceptor()

Method Summary

protected boolean	acceptableName(String name)
protected void	addParametersToContext(ActionContext ac, Map<String,Object> newParams) Adds the parameters into context's ParameterMap
String	doIntercept(ActionInvocation invocation) Subclasses must override to implement the interceptor logic.
protected Set	getExcludeParamsSet() Gets a set of regular expressions of parameters to remove from the parameter map
protected Comparator<String>	getOrderedComparator() Gets an instance of the comparator to use for the ordered sorting.
protected boolean	isAccepted(String paramName)
protected boolean	isExcluded(String paramName)
boolean	isOrdered() Whether to order the parameters or not
protected Map<String,Object>	retrieveParameters(ActionContext ac) Gets the parameter map to apply from wherever appropriate
void	setAcceptParamNames(String commaDelim)
static void	setDevMode(String mode)
void	setExcludeParams(String commaDelim) Sets a comma-delimited list of regular expressions to match parameters that should be removed from the parameter map.
void	setOrdered(boolean ordered) Set whether to order the parameters by object depth or not
protected void	setParameters(Object action, ValueStack stack, Map<String,Object> parameters)
void	setValueStackFactory(ValueStackFactory valueStackFactory)

Methods inherited from class com.opensymphony.xwork2.interceptor.MethodFilterInterceptor

applyInterceptor, getExcludeMethodsSet, getIncludeMethodsSet, intercept, setExcludeMethods, setIncludeMethods

Methods inherited from class com.opensymphony.xwork2.interceptor.AbstractInterceptor

destroy, init

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ParametersInterceptor

public ParametersInterceptor()

Method Detail

setValueStackFactory

public void setValueStackFactory(ValueStackFactory valueStackFactory)

setDevMode

public static void setDevMode(String mode)

setAcceptParamNames

public void setAcceptParamNames(String commaDelim)

doIntercept

public String doIntercept(ActionInvocation invocation)
                   throws Exception

Description copied from class: MethodFilterInterceptor

Subclasses must override to implement the interceptor logic.

Specified by:

doIntercept in class MethodFilterInterceptor

Parameters:

invocation - the action invocation

Returns:

the result of invocation

Throws:

Exception

retrieveParameters

protected Map<String,Object> retrieveParameters(ActionContext ac)

Gets the parameter map to apply from wherever appropriate

Parameters:

ac - The action context

Returns:

The parameter map to apply

addParametersToContext

protected void addParametersToContext(ActionContext ac,
                                      Map<String,Object> newParams)

Adds the parameters into context's ParameterMap

Parameters:

ac - The action context

newParams - The parameter map to apply

In this class this is a no-op, since the parameters were fetched from the same location. In subclasses both retrieveParameters() and addParametersToContext() should be overridden.

setParameters

protected void setParameters(Object action,
                             ValueStack stack,
                             Map<String,Object> parameters)

getOrderedComparator

protected Comparator<String> getOrderedComparator()

Gets an instance of the comparator to use for the ordered sorting. Override this method to customize the ordering of the parameters as they are set to the action.

Returns:

A comparator to sort the parameters

acceptableName

protected boolean acceptableName(String name)

isAccepted

protected boolean isAccepted(String paramName)

isExcluded

protected boolean isExcluded(String paramName)

isOrdered

public boolean isOrdered()

Whether to order the parameters or not

Returns:

True to order

setOrdered

public void setOrdered(boolean ordered)

Set whether to order the parameters by object depth or not

Parameters:

ordered - True to order them

getExcludeParamsSet

protected Set getExcludeParamsSet()

Gets a set of regular expressions of parameters to remove from the parameter map

Returns:

A set of compiled regular expression patterns

setExcludeParams

public void setExcludeParams(String commaDelim)

Sets a comma-delimited list of regular expressions to match parameters that should be removed from the parameter map.

Parameters:

commaDelim - A comma-delimited list of regular expressions