com.opensymphony.xwork2.interceptor: public class: PrefixMethodInvocationUtil

com.opensymphony.xwork2.interceptor
public class: PrefixMethodInvocationUtil [javadoc | source]

java.lang.Object
   com.opensymphony.xwork2.interceptor.PrefixMethodInvocationUtil

A utility class for invoking prefixed methods in action class. Interceptors that made use of this class are:

DefaultWorkflowInterceptor
PrepareInterceptor

In DefaultWorkflowInterceptor

applies only when action implements com.opensymphony.xwork2.Validateable

if the action class have validate{MethodName}(), it will be invoked
else if the action class have validateDo{MethodName}(), it will be invoked
no matter if 1] or 2] is performed, if alwaysInvokeValidate property of the interceptor is "true" (which is by default "true"), validate() will be invoked.

In PrepareInterceptor

Applies only when action implements Preparable

if the action class have prepare{MethodName}(), it will be invoked
else if the action class have prepareDo(MethodName()}(), it will be invoked
no matter if 1] or 2] is performed, if alwaysinvokePrepare property of the interceptor is "true" (which is by default "true"), prepare() will be invoked.

author: Philip - Luppens

author: tm_jee -

Method from com.opensymphony.xwork2.interceptor.PrefixMethodInvocationUtil Summary:
capitalizeMethodName, getPrefixedMethod, invokePrefixMethod

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from com.opensymphony.xwork2.interceptor.PrefixMethodInvocationUtil Detail:
public static String capitalizeMethodName(String methodName) { assert(methodName != null); return methodName.substring(0, 1).toUpperCase() + methodName.substring(1); } This method capitalized the first character of `methodName`. eg. `capitalizeMethodName("someMethod");` will return `"SomeMethod"`.
public static Method getPrefixedMethod(String[] prefixes, String methodName, Object action) { assert(prefixes != null); String capitalizedMethodName = capitalizeMethodName(methodName); for (String prefixe : prefixes) { String prefixedMethodName = prefixe + capitalizedMethodName; try { return action.getClass().getMethod(prefixedMethodName, new Class[0]); } catch (NoSuchMethodException e) { // hmm -- OK, try next prefix if (LOG.isDebugEnabled()) { LOG.debug("cannot find method [" + prefixedMethodName + "] in action [" + action + "]"); } } } return null; } This method returns a Method in `action`. The method returned is found by searching for method in `action` whose method name is equals to the result of appending each `prefixes` to `methodName`. Only the first method found will be returned, hence the order of `prefixes` is important. If none is found this method will return null.
public static void invokePrefixMethod(ActionInvocation actionInvocation, String[] prefixes) throws InvocationTargetException, IllegalAccessException { Object action = actionInvocation.getAction(); String methodName = actionInvocation.getProxy().getMethod(); if (methodName == null) { // if null returns (possible according to the docs), use the default execute methodName = DEFAULT_INVOCATION_METHODNAME; } Method method = getPrefixedMethod(prefixes, methodName, action); if (method != null) { method.invoke(action, new Object[0]); } } This method will prefix `actionInvocation`'s `ActionProxy`'s `method` with `prefixes` before invoking the prefixed method. Order of the `prefixes` is important, as this method will return once a prefixed method is found in the action class. For example, with invokePrefixMethod(actionInvocation, new String[] { "prepare", "prepareDo" }); Assuming `actionInvocation.getProxy(),getMethod()` returns "submit", the order of invocation would be as follows:- prepareSubmit() prepareDoSubmit() If `prepareSubmit()` exists, it will be invoked and this method will return, `prepareDoSubmit()` will NOT be invoked. On the other hand, if `prepareDoSubmit()` does not exists, and `prepareDoSubmit()` exists, it will be invoked. If none of those two methods exists, nothing will be invoked.

Method from com.opensymphony.xwork2.interceptor.PrefixMethodInvocationUtil Detail:

 public static String capitalizeMethodName(String methodName) {
		assert(methodName != null);
		return methodName.substring(0, 1).toUpperCase() + methodName.substring(1);
}

methodName

capitalizeMethodName("someMethod");

"SomeMethod"

 public static Method getPrefixedMethod(String[] prefixes,
    String methodName,
    Object action) {
		assert(prefixes != null);
		String capitalizedMethodName = capitalizeMethodName(methodName);
        for (String prefixe : prefixes) {
            String prefixedMethodName = prefixe + capitalizedMethodName;
            try {
                return action.getClass().getMethod(prefixedMethodName, new Class[0]);
            }
            catch (NoSuchMethodException e) {
                // hmm -- OK, try next prefix
                if (LOG.isDebugEnabled()) {
                    LOG.debug("cannot find method [" + prefixedMethodName + "] in action [" + action + "]");
                }
            }
        }
		return null;
}

Method

action

prefixes

methodName

prefixes

 public static  void invokePrefixMethod(ActionInvocation actionInvocation,
    String[] prefixes) throws InvocationTargetException, IllegalAccessException {
		Object action = actionInvocation.getAction();
		String methodName = actionInvocation.getProxy().getMethod();
		if (methodName == null) {
			// if null returns (possible according to the docs), use the default execute 
	        methodName = DEFAULT_INVOCATION_METHODNAME;
		}
		Method method = getPrefixedMethod(prefixes, methodName, action);
		if (method != null) {
			method.invoke(action, new Object[0]);
		}
}

actionInvocation

ActionProxy

method

prefixes

For example, with

  invokePrefixMethod(actionInvocation, new String[] { "prepare", "prepareDo" });

actionInvocation.getProxy(),getMethod()

prepareSubmit()
prepareDoSubmit()

prepareSubmit()

prepareDoSubmit()

On the other hand, if prepareDoSubmit() does not exists, and prepareDoSubmit() exists, it will be invoked.

If none of those two methods exists, nothing will be invoked.