1 /* 2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.script; 27 28 import java.io.Reader; 29 import java.util.Map; 30 import java.util.Set; 31 32 /** 33 * <code>ScriptEngine</code> is the fundamental interface whose methods must be 34 * fully functional in every implementation of this specification. 35 * <br><br> 36 * These methods provide basic scripting functionality. Applications written to this 37 * simple interface are expected to work with minimal modifications in every implementation. 38 * It includes methods that execute scripts, and ones that set and get values. 39 * <br><br> 40 * The values are key/value pairs of two types. The first type of pairs consists of 41 * those whose keys are reserved and defined in this specification or by individual 42 * implementations. The values in the pairs with reserved keys have specified meanings. 43 * <br><br> 44 * The other type of pairs consists of those that create Java language Bindings, the values are 45 * usually represented in scripts by the corresponding keys or by decorated forms of them. 46 * 47 * @author Mike Grogan 48 * @since 1.6 49 */ 50 51 public interface ScriptEngine { 52 53 /** 54 * Reserved key for a named value that passes 55 * an array of positional arguments to a script. 56 */ 57 public static final String ARGV="javax.script.argv"; 58 59 /** 60 * Reserved key for a named value that is 61 * the name of the file being executed. 62 */ 63 public static final String FILENAME = "javax.script.filename"; 64 65 /** 66 * Reserved key for a named value that is 67 * the name of the <code>ScriptEngine</code> implementation. 68 */ 69 public static final String ENGINE = "javax.script.engine"; 70 71 /** 72 * Reserved key for a named value that identifies 73 * the version of the <code>ScriptEngine</code> implementation. 74 */ 75 public static final String ENGINE_VERSION = "javax.script.engine_version"; 76 77 /** 78 * Reserved key for a named value that identifies 79 * the short name of the scripting language. The name is used by the 80 * <code>ScriptEngineManager</code> to locate a <code>ScriptEngine</code> 81 * with a given name in the <code>getEngineByName</code> method. 82 */ 83 public static final String NAME = "javax.script.name"; 84 85 /** 86 * Reserved key for a named value that is 87 * the full name of Scripting Language supported by the implementation. 88 */ 89 public static final String LANGUAGE = "javax.script.language"; 90 91 /** 92 * Reserved key for the named value that identifies 93 * the version of the scripting language supported by the implementation. 94 */ 95 public static final String LANGUAGE_VERSION ="javax.script.language_version"; 96 97 98 /** 99 * Causes the immediate execution of the script whose source is the String 100 * passed as the first argument. The script may be reparsed or recompiled before 101 * execution. State left in the engine from previous executions, including 102 * variable values and compiled procedures may be visible during this execution. 103 * 104 * @param script The script to be executed by the script engine. 105 * 106 * @param context A <code>ScriptContext</code> exposing sets of attributes in 107 * different scopes. The meanings of the scopes <code>ScriptContext.GLOBAL_SCOPE</code>, 108 * and <code>ScriptContext.ENGINE_SCOPE</code> are defined in the specification. 109 * <br><br> 110 * The <code>ENGINE_SCOPE</code> <code>Bindings</code> of the <code>ScriptContext</code> contains the 111 * bindings of scripting variables to application objects to be used during this 112 * script execution. 113 * 114 * 115 * @return The value returned from the execution of the script. 116 * 117 * @throws ScriptException if an error occurs in script. ScriptEngines should create and throw 118 * <code>ScriptException</code> wrappers for checked Exceptions thrown by underlying scripting 119 * implementations. 120 * @throws NullPointerException if either argument is null. 121 */ eval(String script, ScriptContext context)122 public Object eval(String script, ScriptContext context) throws ScriptException; 123 124 125 /** 126 * Same as <code>eval(String, ScriptContext)</code> where the source of the script 127 * is read from a <code>Reader</code>. 128 * 129 * @param reader The source of the script to be executed by the script engine. 130 * 131 * @param context The <code>ScriptContext</code> passed to the script engine. 132 * 133 * @return The value returned from the execution of the script. 134 * 135 * @throws ScriptException if an error occurs in script. ScriptEngines should create and throw 136 * <code>ScriptException</code> wrappers for checked Exceptions thrown by underlying scripting 137 * implementations. 138 * @throws NullPointerException if either argument is null. 139 */ eval(Reader reader , ScriptContext context)140 public Object eval(Reader reader , ScriptContext context) throws ScriptException; 141 142 /** 143 * Executes the specified script. The default <code>ScriptContext</code> for the <code>ScriptEngine</code> 144 * is used. 145 * 146 * @param script The script language source to be executed. 147 * 148 * @return The value returned from the execution of the script. 149 * 150 * @throws ScriptException if an error occurs in script. ScriptEngines should create and throw 151 * <code>ScriptException</code> wrappers for checked Exceptions thrown by underlying scripting 152 * implementations. 153 * @throws NullPointerException if the argument is null. 154 */ eval(String script)155 public Object eval(String script) throws ScriptException; 156 157 /** 158 * Same as <code>eval(String)</code> except that the source of the script is 159 * provided as a <code>Reader</code> 160 * 161 * @param reader The source of the script. 162 * 163 * @return The value returned by the script. 164 * 165 * @throws ScriptException if an error occurs in script. ScriptEngines should create and throw 166 * <code>ScriptException</code> wrappers for checked Exceptions thrown by underlying scripting 167 * implementations. 168 * @throws NullPointerException if the argument is null. 169 */ eval(Reader reader)170 public Object eval(Reader reader) throws ScriptException; 171 172 /** 173 * Executes the script using the <code>Bindings</code> argument as the <code>ENGINE_SCOPE</code> 174 * <code>Bindings</code> of the <code>ScriptEngine</code> during the script execution. The 175 * <code>Reader</code>, <code>Writer</code> and non-<code>ENGINE_SCOPE</code> <code>Bindings</code> of the 176 * default <code>ScriptContext</code> are used. The <code>ENGINE_SCOPE</code> 177 * <code>Bindings</code> of the <code>ScriptEngine</code> is not changed, and its 178 * mappings are unaltered by the script execution. 179 * 180 * @param script The source for the script. 181 * 182 * @param n The <code>Bindings</code> of attributes to be used for script execution. 183 * 184 * @return The value returned by the script. 185 * 186 * @throws ScriptException if an error occurs in script. ScriptEngines should create and throw 187 * <code>ScriptException</code> wrappers for checked Exceptions thrown by underlying scripting 188 * implementations. 189 * @throws NullPointerException if either argument is null. 190 */ eval(String script, Bindings n)191 public Object eval(String script, Bindings n) throws ScriptException; 192 193 /** 194 * Same as <code>eval(String, Bindings)</code> except that the source of the script 195 * is provided as a <code>Reader</code>. 196 * 197 * @param reader The source of the script. 198 * @param n The <code>Bindings</code> of attributes. 199 * 200 * @return The value returned by the script. 201 * 202 * @throws ScriptException if an error occurs in script. ScriptEngines should create and throw 203 * <code>ScriptException</code> wrappers for checked Exceptions thrown by underlying scripting 204 * implementations. 205 * @throws NullPointerException if either argument is null. 206 */ eval(Reader reader , Bindings n)207 public Object eval(Reader reader , Bindings n) throws ScriptException; 208 209 210 211 /** 212 * Sets a key/value pair in the state of the ScriptEngine that may either create 213 * a Java Language Binding to be used in the execution of scripts or be used in some 214 * other way, depending on whether the key is reserved. Must have the same effect as 215 * <code>getBindings(ScriptContext.ENGINE_SCOPE).put</code>. 216 * 217 * @param key The name of named value to add 218 * @param value The value of named value to add. 219 * 220 * @throws NullPointerException if key is null. 221 * @throws IllegalArgumentException if key is empty. 222 */ put(String key, Object value)223 public void put(String key, Object value); 224 225 226 /** 227 * Retrieves a value set in the state of this engine. The value might be one 228 * which was set using <code>setValue</code> or some other value in the state 229 * of the <code>ScriptEngine</code>, depending on the implementation. Must have the same effect 230 * as <code>getBindings(ScriptContext.ENGINE_SCOPE).get</code> 231 * 232 * @param key The key whose value is to be returned 233 * @return the value for the given key 234 * 235 * @throws NullPointerException if key is null. 236 * @throws IllegalArgumentException if key is empty. 237 */ get(String key)238 public Object get(String key); 239 240 241 /** 242 * Returns a scope of named values. The possible scopes are: 243 * <br><br> 244 * <ul> 245 * <li><code>ScriptContext.GLOBAL_SCOPE</code> - The set of named values representing global 246 * scope. If this <code>ScriptEngine</code> is created by a <code>ScriptEngineManager</code>, 247 * then the manager sets global scope bindings. This may be <code>null</code> if no global 248 * scope is associated with this <code>ScriptEngine</code></li> 249 * <li><code>ScriptContext.ENGINE_SCOPE</code> - The set of named values representing the state of 250 * this <code>ScriptEngine</code>. The values are generally visible in scripts using 251 * the associated keys as variable names.</li> 252 * <li>Any other value of scope defined in the default <code>ScriptContext</code> of the <code>ScriptEngine</code>. 253 * </li> 254 * </ul> 255 * <br><br> 256 * The <code>Bindings</code> instances that are returned must be identical to those returned by the 257 * <code>getBindings</code> method of <code>ScriptContext</code> called with corresponding arguments on 258 * the default <code>ScriptContext</code> of the <code>ScriptEngine</code>. 259 * 260 * @param scope Either <code>ScriptContext.ENGINE_SCOPE</code> or <code>ScriptContext.GLOBAL_SCOPE</code> 261 * which specifies the <code>Bindings</code> to return. Implementations of <code>ScriptContext</code> 262 * may define additional scopes. If the default <code>ScriptContext</code> of the <code>ScriptEngine</code> 263 * defines additional scopes, any of them can be passed to get the corresponding <code>Bindings</code>. 264 * 265 * @return The <code>Bindings</code> with the specified scope. 266 * 267 * @throws IllegalArgumentException if specified scope is invalid 268 * 269 */ getBindings(int scope)270 public Bindings getBindings(int scope); 271 272 /** 273 * Sets a scope of named values to be used by scripts. The possible scopes are: 274 *<br><br> 275 * <ul> 276 * <li><code>ScriptContext.ENGINE_SCOPE</code> - The specified <code>Bindings</code> replaces the 277 * engine scope of the <code>ScriptEngine</code>. 278 * </li> 279 * <li><code>ScriptContext.GLOBAL_SCOPE</code> - The specified <code>Bindings</code> must be visible 280 * as the <code>GLOBAL_SCOPE</code>. 281 * </li> 282 * <li>Any other value of scope defined in the default <code>ScriptContext</code> of the <code>ScriptEngine</code>. 283 *</li> 284 * </ul> 285 * <br><br> 286 * The method must have the same effect as calling the <code>setBindings</code> method of 287 * <code>ScriptContext</code> with the corresponding value of <code>scope</code> on the default 288 * <code>ScriptContext</code> of the <code>ScriptEngine</code>. 289 * 290 * @param bindings The <code>Bindings</code> for the specified scope. 291 * @param scope The specified scope. Either <code>ScriptContext.ENGINE_SCOPE</code>, 292 * <code>ScriptContext.GLOBAL_SCOPE</code>, or any other valid value of scope. 293 * 294 * @throws IllegalArgumentException if the scope is invalid 295 * @throws NullPointerException if the bindings is null and the scope is 296 * <code>ScriptContext.ENGINE_SCOPE</code> 297 */ setBindings(Bindings bindings, int scope)298 public void setBindings(Bindings bindings, int scope); 299 300 301 /** 302 * Returns an uninitialized <code>Bindings</code>. 303 * 304 * @return A <code>Bindings</code> that can be used to replace the state of this <code>ScriptEngine</code>. 305 **/ createBindings()306 public Bindings createBindings(); 307 308 309 /** 310 * Returns the default <code>ScriptContext</code> of the <code>ScriptEngine</code> whose Bindings, Reader 311 * and Writers are used for script executions when no <code>ScriptContext</code> is specified. 312 * 313 * @return The default <code>ScriptContext</code> of the <code>ScriptEngine</code>. 314 */ getContext()315 public ScriptContext getContext(); 316 317 /** 318 * Sets the default <code>ScriptContext</code> of the <code>ScriptEngine</code> whose Bindings, Reader 319 * and Writers are used for script executions when no <code>ScriptContext</code> is specified. 320 * 321 * @param context A <code>ScriptContext</code> that will replace the default <code>ScriptContext</code> in 322 * the <code>ScriptEngine</code>. 323 * @throws NullPointerException if context is null. 324 */ setContext(ScriptContext context)325 public void setContext(ScriptContext context); 326 327 /** 328 * Returns a <code>ScriptEngineFactory</code> for the class to which this <code>ScriptEngine</code> belongs. 329 * 330 * @return The <code>ScriptEngineFactory</code> 331 */ getFactory()332 public ScriptEngineFactory getFactory(); 333 } 334