    001// Copyright 2007, 2008, 2010, 2011 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007//     http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.internal.services;
    016
    017import org.apache.tapestry5.ComponentEventCallback;
    018import org.apache.tapestry5.TapestryMarkers;
    019import org.apache.tapestry5.ioc.Invokable;
    020import org.apache.tapestry5.ioc.OperationTracker;
    021import org.apache.tapestry5.runtime.Event;
    022import org.slf4j.Logger;
    023
    024@SuppressWarnings("all")
    025public class EventImpl implements Event
    026{
    027    private boolean aborted;
    028
    029    private String methodDescription;
    030
    031    private final ComponentEventCallback handler;
    032
    033    private final Logger logger;
    034
    035    private final boolean debugEnabled;
    036
    037    protected final OperationTracker tracker;
    038
    039    /**
    040     * @param handler informed of return values from methods, deems when the event is aborted
    041     * @param logger  used to log method invocations
    042     * @param tracker
    043     */
    044    public EventImpl(ComponentEventCallback handler, Logger logger, OperationTracker tracker)
    045    {
    046        this.tracker = tracker;
    047        assert handler != null;
    048        this.handler = handler;
    049        this.logger = logger;
    050
    051        // TAP5-471: Thousands of calls to isDebugEnabled() do add up
    052        debugEnabled = logger.isDebugEnabled();
    053    }
    054
    055    public boolean isAborted()
    056    {
    057        return aborted;
    058    }
    059
    060    public void setMethodDescription(String methodDescription)
    061    {
    062        if (debugEnabled)
    063            logger.debug(TapestryMarkers.EVENT_HANDLER_METHOD, "Invoking: " + methodDescription);
    064
    065        this.methodDescription = methodDescription;
    066    }
    067
    068    @SuppressWarnings("unchecked")
    069    public boolean storeResult(final Object result)
    070    {
    071        // Given that this method is *only* invoked from code
    072        // that is generated at runtime and proven to be correct,
    073        // this should never, ever happen. But what the hell,
    074        // let's check anyway.
    075
    076        if (aborted)
    077        {
    078            throw new IllegalStateException(String.format("Can not store result from invoking method %s, because an event result value has already been obtained from some other event handler method.", methodDescription));
    079        }
    080
    081
    082        if (result != null)
    083        {
    084            boolean handleResult =
    085                    tracker.invoke("Handling result from method " + methodDescription + '.', new Invokable<Boolean>()
    086                    {
    087                        public Boolean invoke()
    088                        {
    089                            return handler.handleResult(result);
    090                        }
    091                    });
    092
    093            aborted |= handleResult;
    094        }
    095
    096        return aborted;
    097    }
    098
    099    protected String getMethodDescription()
    100    {
    101        return methodDescription;
    102    }
    103}