ActivationContextDefinition.java

package com.wooki.services.security;

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

import org.apache.tapestry5.EventConstants;
import org.apache.tapestry5.EventContext;
import org.apache.tapestry5.annotations.OnEvent;
import org.apache.tapestry5.internal.EmptyEventContext;

/**
 * Object used to store the information related to activation context for a given page.
 * 
 * @author ccordenier
 */
public class ActivationContextDefinition
{

    static final String OBJECT_ARRAY_TYPE = "java.lang.Object[]";

    static final String EVENT_CONTEXT_TYPE = EventContext.class.getName();

    static final String LIST_TYPE = List.class.getName();

    private final static int ANY_NUMBER_OF_PARAMETERS = -1;

    /**
     * The list of method definition for activation context for this class.
     */
    private List<Class[]> authorizedActivationContext = new ArrayList<Class[]>();

    /**
     * Tag this page as unsecured
     */
    private boolean unsecured;

    /**
     * Create the activation context definition for the given class.
     * 
     * @param clazz
     */
    public ActivationContextDefinition(Class clazz)
    {

        Method[] methods = clazz.getMethods();

        for (Method method : methods)
        {

            OnEvent eventHandler = method.getAnnotation(OnEvent.class);

            if ((eventHandler != null && EventConstants.ACTIVATE.equals(eventHandler.value()))
                    || ("on" + EventConstants.ACTIVATE).equalsIgnoreCase(method.getName()))
            {

                // Check parameters
                Class[] parameterType = method.getParameterTypes();
                int count = getParameterCount(parameterType);

                if (ANY_NUMBER_OF_PARAMETERS == count)
                {
                    this.unsecured = true;
                    this.authorizedActivationContext.clear();
                    break;
                }

                this.authorizedActivationContext.add(parameterType);
            }

        }
    }

    /**
     * This method must be called to check if the activation context of the current request
     * correspond to an existing matching method.
     * 
     * @param pageName
     * @param ctx
     * @return
     */
    public boolean findMatchingMethod(String pageName, EventContext ctx)
    {

        // First check unsecure flag
        if (unsecured) { return true; }

        // No activation context method inside class
        if (this.authorizedActivationContext.size() == 0) { return EmptyEventContext.class
                .equals(ctx.getClass()); }

        // Check the list of parameter types arrays
        for (Class[] parameterType : this.authorizedActivationContext)
        {
            if (parameterType.length == ctx.getCount())
            {

                // If no parameter to check return true
                if (ctx.getCount() == 0) { return true; }

                for (int i = 0; i < parameterType.length; i++)
                {
                    Class type = parameterType[i];
                    try
                    {
                        ctx.get(type, i);
                        if (i == parameterType.length - 1) { return true; }
                    }
                    catch (RuntimeException re)
                    {
                        break;
                    }
                }
            }
        }

        return false;

    }

    private int getParameterCount(Class[] types)
    {

        if (types.length == 0) return 0;

        if (types.length == 1)
        {
            String soloType = types[0].getName();

            if (soloType.equals(OBJECT_ARRAY_TYPE) || soloType.equals(EVENT_CONTEXT_TYPE)
                    || soloType.equals(LIST_TYPE)) return ANY_NUMBER_OF_PARAMETERS;
        }

        return types.length;
    }

}