001 // Copyright 2004, 2005 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. 014 015 package org.apache.tapestry.callback; 016 017 import org.apache.hivemind.ApplicationRuntimeException; 018 import org.apache.hivemind.util.Defense; 019 import org.apache.tapestry.IExternalPage; 020 import org.apache.tapestry.IRequestCycle; 021 022 /** 023 * A callback for returning to an {@link org.apache.tapestry.IExternalPage}. 024 * <p> 025 * Example usage of <tt>ExternalCallback</tt>: 026 * <p> 027 * The External page ensure a user is authenticated in the 028 * {@link org.apache.tapestry.IPage#validate(IRequestCycle)} method. If the user is not 029 * authenticated, they are redirected to the Login page, after setting a callback in the Login page. 030 * <p> 031 * The Login page <tt>formSubmit()</tt> {@link org.apache.tapestry.IActionListener} authenticates 032 * the user and then invokes {@link ICallback#performCallback(IRequestCycle)} to the External page. 033 * 034 * <pre> 035 * 036 * 037 * 038 * 039 * 040 * 041 * 042 * 043 * 044 * 045 * 046 * public class External extends BasePage implements IExternalPage { 047 * 048 * private Integer _itemId; 049 * 050 * public void validate(IRequestCycle cycle) throws RequestCycleException { 051 * Visit visit = (Visit) getVisit(); 052 * 053 * if (!visit.isAuthenticated()) { 054 * Login login = (Login) cycle.getPage("Login"); 055 * 056 * login.setCallback 057 * (new ExternalCallback(this, cycle.getServiceParameters())); 058 * 059 * throw new PageRedirectException(login); 060 * } 061 * } 062 * 063 * public void activateExternalPage(Object[] params, IRequestCycle cycle) 064 * throws RequestCycleException { 065 * _itemId = (Integer) params[0]; 066 * } 067 * } 068 * 069 * public Login extends BasePage { 070 * 071 * private ICallback _callback; 072 * 073 * public void setCallback(ICallback _callback) { 074 * _callback = callback; 075 * } 076 * 077 * public void formSubmit(IRequestCycle cycle) { 078 * // Authentication code 079 * .. 080 * 081 * Visit visit = (Visit) getVisit(); 082 * 083 * visit.setAuthenticated(true); 084 * 085 * if (_callback != null) { 086 * _callback.performCallback(cycle); 087 * } 088 * } 089 * } 090 * 091 * 092 * 093 * 094 * 095 * 096 * 097 * 098 * 099 * 100 * 101 * </pre> 102 * 103 * @see org.apache.tapestry.IExternalPage 104 * @see org.apache.tapestry.engine.ExternalService 105 * @author Malcolm Edgar 106 * @since 2.3 107 */ 108 109 public class ExternalCallback implements ICallback 110 { 111 private static final long serialVersionUID = -6783421589702643930L; 112 113 private String _pageName; 114 115 private Object[] _parameters; 116 117 /** 118 * Creates a new ExternalCallback for the named <tt>IExternalPage</tt>. The parameters (which 119 * may be null) is retained, not copied. 120 */ 121 122 public ExternalCallback(String pageName, Object[] parameters) 123 { 124 Defense.notNull(pageName, "pageName"); 125 126 _pageName = pageName; 127 _parameters = parameters; 128 } 129 130 /** 131 * Creates a new ExternalCallback for the page. The parameters (which may be null) is retained, 132 * not copied. 133 */ 134 135 public ExternalCallback(IExternalPage page, Object[] parameters) 136 { 137 Defense.notNull(page, "page"); 138 139 _pageName = page.getPageName(); 140 _parameters = parameters; 141 } 142 143 /** 144 * Invokes {@link IRequestCycle#setPage(String)} to select the previously identified 145 * <tt>IExternalPage</tt> as the response page and activates the page by invoking 146 * <tt>activateExternalPage()</tt> with the callback parameters and request cycle. 147 */ 148 149 public void performCallback(IRequestCycle cycle) 150 { 151 Defense.notNull(cycle, "cycle"); 152 153 try 154 { 155 IExternalPage page = (IExternalPage) cycle.getPage(_pageName); 156 157 cycle.activate(page); 158 159 page.activateExternalPage(_parameters, cycle); 160 } 161 catch (ClassCastException ex) 162 { 163 throw new ApplicationRuntimeException(CallbackMessages.pageNotExternal(_pageName), ex); 164 } 165 } 166 167 public String toString() 168 { 169 StringBuffer buffer = new StringBuffer("ExternalCallback["); 170 171 buffer.append(_pageName); 172 173 if (_parameters != null) 174 { 175 for (int i = 0; i < _parameters.length; i++) 176 { 177 if (i == 0) 178 buffer.append('/'); 179 else 180 buffer.append(", "); 181 182 buffer.append(_parameters[i]); 183 } 184 } 185 186 buffer.append(']'); 187 188 return buffer.toString(); 189 } 190 }