J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2005 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.script; |
| 27 | |
| 28 | import java.util.List; |
| 29 | |
| 30 | /** |
| 31 | * <code>ScriptEngineFactory</code> is used to describe and instantiate |
| 32 | * <code>ScriptEngines</code>. |
| 33 | * <br><br> |
| 34 | * Each class implementing <code>ScriptEngine</code> has a corresponding factory |
| 35 | * that exposes metadata describing the engine class. |
| 36 | * <br><br>The <code>ScriptEngineManager</code> |
| 37 | * uses the service provider mechanism described in the <i>Jar File Specification</i> to obtain |
| 38 | * instances of all <code>ScriptEngineFactories</code> available in |
| 39 | * the current ClassLoader. |
| 40 | * |
| 41 | * @since 1.6 |
| 42 | */ |
| 43 | public interface ScriptEngineFactory { |
| 44 | /** |
| 45 | * Returns the full name of the <code>ScriptEngine</code>. For |
| 46 | * instance an implementation based on the Mozilla Rhino Javascript engine |
| 47 | * might return <i>Rhino Mozilla Javascript Engine</i>. |
| 48 | * @return The name of the engine implementation. |
| 49 | */ |
| 50 | public String getEngineName(); |
| 51 | |
| 52 | /** |
| 53 | * Returns the version of the <code>ScriptEngine</code>. |
| 54 | * @return The <code>ScriptEngine</code> implementation version. |
| 55 | */ |
| 56 | public String getEngineVersion(); |
| 57 | |
| 58 | |
| 59 | /** |
| 60 | * Returns an immutable list of filename extensions, which generally identify scripts |
| 61 | * written in the language supported by this <code>ScriptEngine</code>. |
| 62 | * The array is used by the <code>ScriptEngineManager</code> to implement its |
| 63 | * <code>getEngineByExtension</code> method. |
| 64 | * @return The list of extensions. |
| 65 | */ |
| 66 | public List<String> getExtensions(); |
| 67 | |
| 68 | |
| 69 | /** |
| 70 | * Returns an immutable list of mimetypes, associated with scripts that |
| 71 | * can be executed by the engine. The list is used by the |
| 72 | * <code>ScriptEngineManager</code> class to implement its |
| 73 | * <code>getEngineByMimetype</code> method. |
| 74 | * @return The list of mime types. |
| 75 | */ |
| 76 | public List<String> getMimeTypes(); |
| 77 | |
| 78 | /** |
| 79 | * Returns an immutable list of short names for the <code>ScriptEngine</code>, which may be used to |
| 80 | * identify the <code>ScriptEngine</code> by the <code>ScriptEngineManager</code>. |
| 81 | * For instance, an implementation based on the Mozilla Rhino Javascript engine might |
| 82 | * return list containing {"javascript", "rhino"}. |
| 83 | */ |
| 84 | public List<String> getNames(); |
| 85 | |
| 86 | /** |
| 87 | * Returns the name of the scripting langauge supported by this |
| 88 | * <code>ScriptEngine</code>. |
| 89 | * @return The name of the supported language. |
| 90 | */ |
| 91 | public String getLanguageName(); |
| 92 | |
| 93 | /** |
| 94 | * Returns the version of the scripting language supported by this |
| 95 | * <code>ScriptEngine</code>. |
| 96 | * @return The version of the supported language. |
| 97 | */ |
| 98 | public String getLanguageVersion(); |
| 99 | |
| 100 | /** |
| 101 | * Returns the value of an attribute whose meaning may be implementation-specific. |
| 102 | * Keys for which the value is defined in all implementations are: |
| 103 | * <ul> |
| 104 | * <li>ScriptEngine.ENGINE</li> |
| 105 | * <li>ScriptEngine.ENGINE_VERSION</li> |
| 106 | * <li>ScriptEngine.NAME</li> |
| 107 | * <li>ScriptEngine.LANGUAGE</li> |
| 108 | * <li>ScriptEngine.LANGUAGE_VERSION</li> |
| 109 | * </ul> |
| 110 | * <p> |
| 111 | * The values for these keys are the Strings returned by <code>getEngineName</code>, |
| 112 | * <code>getEngineVersion</code>, <code>getName</code>, <code>getLanguageName</code> and |
| 113 | * <code>getLanguageVersion</code> respectively.<br><br> |
| 114 | * A reserved key, <code><b>THREADING</b></code>, whose value describes the behavior of the engine |
| 115 | * with respect to concurrent execution of scripts and maintenance of state is also defined. |
| 116 | * These values for the <code><b>THREADING</b></code> key are:<br><br> |
| 117 | * <ul> |
| 118 | * <p><code>null</code> - The engine implementation is not thread safe, and cannot |
| 119 | * be used to execute scripts concurrently on multiple threads. |
| 120 | * <p><code>"MULTITHREADED"</code> - The engine implementation is internally |
| 121 | * thread-safe and scripts may execute concurrently although effects of script execution |
| 122 | * on one thread may be visible to scripts on other threads. |
| 123 | * <p><code>"THREAD-ISOLATED"</code> - The implementation satisfies the requirements |
| 124 | * of "MULTITHREADED", and also, the engine maintains independent values |
| 125 | * for symbols in scripts executing on different threads. |
| 126 | * <p><code>"STATELESS"</code> - The implementation satisfies the requirements of |
| 127 | * <code>"THREAD-ISOLATED"</code>. In addition, script executions do not alter the |
| 128 | * mappings in the <code>Bindings</code> which is the engine scope of the |
| 129 | * <code>ScriptEngine</code>. In particular, the keys in the <code>Bindings</code> |
| 130 | * and their associated values are the same before and after the execution of the script. |
| 131 | * </li> |
| 132 | * </ul> |
| 133 | * <br><br> |
| 134 | * Implementations may define implementation-specific keys. |
| 135 | * |
| 136 | * @param key The name of the parameter |
| 137 | * @return The value for the given parameter. Returns <code>null</code> if no |
| 138 | * value is assigned to the key. |
| 139 | * |
| 140 | */ |
| 141 | public Object getParameter(String key); |
| 142 | |
| 143 | /** |
| 144 | * Returns a String which can be used to invoke a method of a Java object using the syntax |
| 145 | * of the supported scripting language. For instance, an implementaton for a Javascript |
| 146 | * engine might be; |
| 147 | * <p> |
| 148 | * <code><pre> |
| 149 | * public String getMethodCallSyntax(String obj, |
| 150 | * String m, String... args) { |
| 151 | * String ret = obj; |
| 152 | * ret += "." + m + "("; |
| 153 | * for (int i = 0; i < args.length; i++) { |
| 154 | * ret += args[i]; |
| 155 | * if (i == args.length - 1) { |
| 156 | * ret += ")"; |
| 157 | * } else { |
| 158 | * ret += ","; |
| 159 | * } |
| 160 | * } |
| 161 | * return ret; |
| 162 | * } |
| 163 | *</pre></code> |
| 164 | * <p> |
| 165 | * |
| 166 | * @param obj The name representing the object whose method is to be invoked. The |
| 167 | * name is the one used to create bindings using the <code>put</code> method of |
| 168 | * <code>ScriptEngine</code>, the <code>put</code> method of an <code>ENGINE_SCOPE</code> |
| 169 | * <code>Bindings</code>,or the <code>setAttribute</code> method |
| 170 | * of <code>ScriptContext</code>. The identifier used in scripts may be a decorated form of the |
| 171 | * specified one. |
| 172 | * |
| 173 | * @param m The name of the method to invoke. |
| 174 | * @param args names of the arguments in the method call. |
| 175 | * |
| 176 | * @return The String used to invoke the method in the syntax of the scripting language. |
| 177 | */ |
| 178 | public String getMethodCallSyntax(String obj, String m, String... args); |
| 179 | |
| 180 | /** |
| 181 | * Returns a String that can be used as a statement to display the specified String using |
| 182 | * the syntax of the supported scripting language. For instance, the implementaton for a Perl |
| 183 | * engine might be; |
| 184 | * <p> |
| 185 | * <pre><code> |
| 186 | * public String getOutputStatement(String toDisplay) { |
| 187 | * return "print(" + toDisplay + ")"; |
| 188 | * } |
| 189 | * </code></pre> |
| 190 | * |
| 191 | * @param toDisplay The String to be displayed by the returned statement. |
| 192 | * @return The string used to display the String in the syntax of the scripting language. |
| 193 | * |
| 194 | * |
| 195 | */ |
| 196 | public String getOutputStatement(String toDisplay); |
| 197 | |
| 198 | |
| 199 | /** |
| 200 | * Returns A valid scripting language executable progam with given statements. |
| 201 | * For instance an implementation for a PHP engine might be: |
| 202 | * <p> |
| 203 | * <pre><code> |
| 204 | * public String getProgram(String... statements) { |
| 205 | * $retval = "<?\n"; |
| 206 | * int len = statements.length; |
| 207 | * for (int i = 0; i < len; i++) { |
| 208 | * $retval += statements[i] + ";\n"; |
| 209 | * } |
| 210 | * $retval += "?>"; |
| 211 | * |
| 212 | * } |
| 213 | * </code></pre> |
| 214 | * |
| 215 | * @param statements The statements to be executed. May be return values of |
| 216 | * calls to the <code>getMethodCallSyntax</code> and <code>getOutputStatement</code> methods. |
| 217 | * @return The Program |
| 218 | */ |
| 219 | |
| 220 | public String getProgram(String... statements); |
| 221 | |
| 222 | /** |
| 223 | * Returns an instance of the <code>ScriptEngine</code> associated with this |
| 224 | * <code>ScriptEngineFactory</code>. A new ScriptEngine is generally |
| 225 | * returned, but implementations may pool, share or reuse engines. |
| 226 | * |
| 227 | * @return A new <code>ScriptEngine</code> instance. |
| 228 | */ |
| 229 | public ScriptEngine getScriptEngine(); |
| 230 | } |