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1 /* |
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2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 package javax.activation; |
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27 |
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28 import java.util.Map; |
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29 import java.util.WeakHashMap; |
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30 |
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31 |
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32 /** |
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33 * The CommandMap class provides an interface to a registry of |
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34 * command objects available in the system. |
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35 * Developers are expected to either use the CommandMap |
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36 * implementation included with this package (MailcapCommandMap) or |
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37 * develop their own. Note that some of the methods in this class are |
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38 * abstract. |
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39 * |
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40 * @since 1.6 |
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41 */ |
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42 public abstract class CommandMap { |
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43 private static CommandMap defaultCommandMap = null; |
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44 private static Map<ClassLoader,CommandMap> map = |
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45 new WeakHashMap<ClassLoader,CommandMap>(); |
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46 |
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47 /** |
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48 * Get the default CommandMap. |
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49 * |
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50 * <ul> |
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51 * <li> In cases where a CommandMap instance has been previously set |
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52 * to some value (via <i>setDefaultCommandMap</i>) |
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53 * return the CommandMap. |
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54 * <li> |
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55 * In cases where no CommandMap has been set, the CommandMap |
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56 * creates an instance of {@code MailcapCommandMap} and |
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57 * set that to the default, returning its value. |
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58 * |
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59 * </ul> |
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60 * |
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61 * @return the CommandMap |
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62 */ |
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63 public static synchronized CommandMap getDefaultCommandMap() { |
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64 if (defaultCommandMap != null) |
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65 return defaultCommandMap; |
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66 |
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67 // fetch per-thread-context-class-loader default |
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68 ClassLoader tccl = SecuritySupport.getContextClassLoader(); |
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69 CommandMap def = map.get(tccl); |
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70 if (def == null) { |
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71 def = new MailcapCommandMap(); |
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72 map.put(tccl, def); |
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73 } |
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74 return def; |
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75 } |
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76 |
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77 /** |
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78 * Set the default CommandMap. Reset the CommandMap to the default by |
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79 * calling this method with {@code null}. |
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80 * |
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81 * @param commandMap The new default CommandMap. |
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82 * @exception SecurityException if the caller doesn't have permission |
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83 * to change the default |
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84 */ |
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85 public static synchronized void setDefaultCommandMap(CommandMap commandMap) { |
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86 SecurityManager security = System.getSecurityManager(); |
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87 if (security != null) { |
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88 try { |
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89 // if it's ok with the SecurityManager, it's ok with me... |
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90 security.checkSetFactory(); |
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91 } catch (SecurityException ex) { |
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92 // otherwise, we also allow it if this code and the |
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93 // factory come from the same (non-system) class loader (e.g., |
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94 // the JAF classes were loaded with the applet classes). |
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95 ClassLoader cl = CommandMap.class.getClassLoader(); |
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96 if (cl == null || cl.getParent() == null || |
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97 cl != commandMap.getClass().getClassLoader()) { |
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98 throw ex; |
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99 } |
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100 } |
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101 } |
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102 // remove any per-thread-context-class-loader CommandMap |
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103 map.remove(SecuritySupport.getContextClassLoader()); |
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104 defaultCommandMap = commandMap; |
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105 } |
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106 |
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107 /** |
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108 * Get the preferred command list from a MIME Type. The actual semantics |
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109 * are determined by the implementation of the CommandMap. |
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110 * |
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111 * @param mimeType the MIME type |
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112 * @return the CommandInfo classes that represent the command Beans. |
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113 */ |
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114 abstract public CommandInfo[] getPreferredCommands(String mimeType); |
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115 |
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116 /** |
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117 * Get the preferred command list from a MIME Type. The actual semantics |
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118 * are determined by the implementation of the CommandMap. <p> |
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119 * |
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120 * The {@code DataSource} provides extra information, such as |
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121 * the file name, that a CommandMap implementation may use to further |
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122 * refine the list of commands that are returned. The implementation |
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123 * in this class simply calls the {@code getPreferredCommands} |
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124 * method that ignores this argument. |
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125 * |
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126 * @param mimeType the MIME type |
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127 * @param ds a DataSource for the data |
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128 * @return the CommandInfo classes that represent the command Beans. |
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129 * @since 1.6, JAF 1.1 |
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130 */ |
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131 public CommandInfo[] getPreferredCommands(String mimeType, DataSource ds) { |
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132 return getPreferredCommands(mimeType); |
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133 } |
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134 |
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135 /** |
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136 * Get all the available commands for this type. This method |
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137 * should return all the possible commands for this MIME type. |
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138 * |
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139 * @param mimeType the MIME type |
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140 * @return the CommandInfo objects representing all the commands. |
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141 */ |
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142 abstract public CommandInfo[] getAllCommands(String mimeType); |
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143 |
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144 /** |
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145 * Get all the available commands for this type. This method |
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146 * should return all the possible commands for this MIME type. <p> |
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147 * |
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148 * The {@code DataSource} provides extra information, such as |
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149 * the file name, that a CommandMap implementation may use to further |
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150 * refine the list of commands that are returned. The implementation |
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151 * in this class simply calls the {@code getAllCommands} |
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152 * method that ignores this argument. |
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153 * |
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154 * @param mimeType the MIME type |
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155 * @param ds a DataSource for the data |
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156 * @return the CommandInfo objects representing all the commands. |
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157 * @since 1.6, JAF 1.1 |
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158 */ |
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159 public CommandInfo[] getAllCommands(String mimeType, DataSource ds) { |
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160 return getAllCommands(mimeType); |
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161 } |
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162 |
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163 /** |
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164 * Get the default command corresponding to the MIME type. |
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165 * |
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166 * @param mimeType the MIME type |
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167 * @param cmdName the command name |
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168 * @return the CommandInfo corresponding to the command. |
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169 */ |
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170 abstract public CommandInfo getCommand(String mimeType, String cmdName); |
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171 |
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172 /** |
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173 * Get the default command corresponding to the MIME type. <p> |
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174 * |
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175 * The {@code DataSource} provides extra information, such as |
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176 * the file name, that a CommandMap implementation may use to further |
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177 * refine the command that is chosen. The implementation |
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178 * in this class simply calls the {@code getCommand} |
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179 * method that ignores this argument. |
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180 * |
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181 * @param mimeType the MIME type |
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182 * @param cmdName the command name |
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183 * @param ds a DataSource for the data |
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184 * @return the CommandInfo corresponding to the command. |
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185 * @since 1.6, JAF 1.1 |
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186 */ |
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187 public CommandInfo getCommand(String mimeType, String cmdName, |
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188 DataSource ds) { |
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189 return getCommand(mimeType, cmdName); |
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190 } |
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191 |
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192 /** |
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193 * Locate a DataContentHandler that corresponds to the MIME type. |
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194 * The mechanism and semantics for determining this are determined |
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195 * by the implementation of the particular CommandMap. |
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196 * |
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197 * @param mimeType the MIME type |
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198 * @return the DataContentHandler for the MIME type |
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199 */ |
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200 abstract public DataContentHandler createDataContentHandler(String |
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201 mimeType); |
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202 |
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203 /** |
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204 * Locate a DataContentHandler that corresponds to the MIME type. |
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205 * The mechanism and semantics for determining this are determined |
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206 * by the implementation of the particular CommandMap. <p> |
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207 * |
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208 * The {@code DataSource} provides extra information, such as |
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209 * the file name, that a CommandMap implementation may use to further |
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210 * refine the choice of DataContentHandler. The implementation |
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211 * in this class simply calls the {@code createDataContentHandler} |
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212 * method that ignores this argument. |
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213 * |
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214 * @param mimeType the MIME type |
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215 * @param ds a DataSource for the data |
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216 * @return the DataContentHandler for the MIME type |
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217 * @since 1.6, JAF 1.1 |
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218 */ |
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219 public DataContentHandler createDataContentHandler(String mimeType, |
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220 DataSource ds) { |
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221 return createDataContentHandler(mimeType); |
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222 } |
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223 |
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224 /** |
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225 * Get all the MIME types known to this command map. |
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226 * If the command map doesn't support this operation, |
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227 * null is returned. |
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228 * |
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229 * @return array of MIME types as strings, or null if not supported |
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230 * @since 1.6, JAF 1.1 |
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231 */ |
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232 public String[] getMimeTypes() { |
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233 return null; |
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234 } |
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235 } |