geirm 01/04/19 21:29:28 Added: src/java/org/apache/velocity/context EventCartridge.java Log: Initial checkin of the EventCartridge. Revision Changes Path 1.1 jakarta-velocity/src/java/org/apache/velocity/context/EventCartridge.java Index: EventCartridge.java =================================================================== package org.apache.velocity.context; /* * The Apache Software License, Version 1.1 * * Copyright (c) 2001 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, if * any, must include the following acknowlegement: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. The names "The Jakarta Project", "Velocity", and "Apache Software * Foundation" must not be used to endorse or promote products derived * from this software without prior written permission. For written * permission, please contact [EMAIL PROTECTED] * * 5. Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Group. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. */ import org.apache.velocity.context.InternalHousekeepingContext; import org.apache.velocity.context.Context; import java.util.ArrayList; /** * 'Package' of event handlers... * * @author <a href="mailto:[EMAIL PROTECTED]">Geir Magnusson Jr.</a> * @author <a href="mailto:[EMAIL PROTECTED]">Jose Alberto Fernandez</a> * @version $Id: EventCartridge.java,v 1.1 2001/04/20 04:29:28 geirm Exp $ */ public class EventCartridge implements ReferenceInsertionEventHandler, NullSetEventHandler, NullReferenceEventHandler, MethodExceptionEventHandler { private ReferenceInsertionEventHandler rieh = null; private NullSetEventHandler nseh = null; private NullReferenceEventHandler nreh = null; private MethodExceptionEventHandler meeh = null; /** * Adds an event handler(s) to the Cartridge. This method * will find all possible event handler interfaces supported * by the passed in object. * * @param ev object impementing a valid EventHandler-derived interface * @return true if a supported interface, false otherwise or if null */ public boolean addEventHandler( EventHandler ev ) { if (ev == null) { return false; } boolean found = false; if ( ev instanceof ReferenceInsertionEventHandler) { rieh = (ReferenceInsertionEventHandler) ev; found = true; } if ( ev instanceof NullReferenceEventHandler ) { nreh = (NullReferenceEventHandler) ev; found = true; } if ( ev instanceof NullSetEventHandler ) { nseh = (NullSetEventHandler) ev; found = true; } if ( ev instanceof MethodExceptionEventHandler ) { meeh = (MethodExceptionEventHandler) ev; found = true; } return found; } /** * Removes an event handler(s) from the Cartridge. This method * will find all possible event handler interfaces supported * by the passed in object and remove them. * * @param ev object impementing a valid EventHandler-derived interface * @return true if a supported interface, false otherwise or if null */ public boolean removeEventHandler(EventHandler ev) { if ( ev == null ) { return false; } boolean found = false; if (ev == rieh) { rieh = null; found = true; } if (ev == nseh) { nseh = null; found = true; } if (ev == nreh) { nreh = null; found = true; } if (ev == meeh) { meeh = null; found = true; } return found; } /** * Implementation of ReferenceInsertionEventHandler method * <code>referenceInsert()</code>. * * Called during Velocity merge before a reference value will * be inserted into the output stream. * * @param reference reference from template about to be inserted * @param value value about to be inserted (after toString() ) * @return Object on which toString() should be called for output. */ public Object referenceInsert( String reference, Object value ) { if (rieh == null) { return value; } return rieh.referenceInsert( reference, value ); } /** * Implementation of NullSetEventHandler method * <code>nullSetLogMessage()</code>. * * Called during Velocity merge to determine if when * a #set() results in a null assignment, a warning * is logged. * * @param reference reference from template about to be inserted * @return true if to be logged, false otherwise */ public boolean nullSetLogMessage( String reference ) { if ( nseh == null) { return true; } return nseh.nullSetLogMessage( reference ); } /** * Implementation of NullReferenceEventHandler method * <code>nullReferenceRender()</code>. * * Called during Velocity merge if a reference is null * * @param reference reference from template about to be inserted * @return Object to render into output, or null if normal behavior is desired */ public Object nullReferenceRender( String reference ) { if (nreh == null) { return reference; } return nreh.nullReferenceRender( reference ); } /** * Implementation of MethodExceptionEventHandler method * <code>methodException()</code>. * * Called during Velocity merge if a reference is null * * @param claz Class that is causing the exception * @param method method called that causes the exception * @param e Exception thrown by the method * @return Object to return as method result * @throws exception to be wrapped and propogated to app */ public Object methodException( Class claz, String method, Exception e ) throws Exception { /* * if we don't have a handler, just throw what we were handed */ if (meeh == null) { throw e; } /* * otherwise, call it.. */ return meeh.methodException( claz, method, e ); } /** * Attached the EventCartridge to the context * * Final because not something one should mess with lightly :) * * @param context context to attach to * @return true if successful, false otherwise */ public final boolean attachToContext( Context context ) { if ( context instanceof InternalHousekeepingContext ) { InternalHousekeepingContext icb = (InternalHousekeepingContext) context; icb.attachEventCartridge( this ); return true; } else { return false; } } }
