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| 1 | +/* | |
| 2 | + * Copyright (c) 2005, 2006, 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.util.*; | |
| 29 | +import java.io.*; | |
| 30 | + | |
| 31 | +/** | |
| 32 | + * Simple implementation of ScriptContext. | |
| 33 | + * | |
| 34 | + * @author Mike Grogan | |
| 35 | + * @since 1.6 | |
| 36 | + */ | |
| 37 | +public class SimpleScriptContext implements ScriptContext { | |
| 38 | + | |
| 39 | + /** | |
| 40 | + * This is the writer to be used to output from scripts. | |
| 41 | + * By default, a <code>PrintWriter</code> based on <code>System.out</code> | |
| 42 | + * is used. Accessor methods getWriter, setWriter are used to manage | |
| 43 | + * this field. | |
| 44 | + * @see java.lang.System#out | |
| 45 | + * @see java.io.PrintWriter | |
| 46 | + */ | |
| 47 | + protected Writer writer; | |
| 48 | + | |
| 49 | + /** | |
| 50 | + * This is the writer to be used to output errors from scripts. | |
| 51 | + * By default, a <code>PrintWriter</code> based on <code>System.err</code> is | |
| 52 | + * used. Accessor methods getErrorWriter, setErrorWriter are used to manage | |
| 53 | + * this field. | |
| 54 | + * @see java.lang.System#err | |
| 55 | + * @see java.io.PrintWriter | |
| 56 | + */ | |
| 57 | + protected Writer errorWriter; | |
| 58 | + | |
| 59 | + /** | |
| 60 | + * This is the reader to be used for input from scripts. | |
| 61 | + * By default, a <code>InputStreamReader</code> based on <code>System.in</code> | |
| 62 | + * is used and default charset is used by this reader. Accessor methods | |
| 63 | + * getReader, setReader are used to manage this field. | |
| 64 | + * @see java.lang.System#in | |
| 65 | + * @see java.io.InputStreamReader | |
| 66 | + */ | |
| 67 | + protected Reader reader; | |
| 68 | + | |
| 69 | + | |
| 70 | + /** | |
| 71 | + * This is the engine scope bindings. | |
| 72 | + * By default, a <code>SimpleBindings</code> is used. Accessor | |
| 73 | + * methods setBindings, getBindings are used to manage this field. | |
| 74 | + * @see SimpleBindings | |
| 75 | + */ | |
| 76 | + protected Bindings engineScope; | |
| 77 | + | |
| 78 | + /** | |
| 79 | + * This is the global scope bindings. | |
| 80 | + * By default, a null value (which means no global scope) is used. Accessor | |
| 81 | + * methods setBindings, getBindings are used to manage this field. | |
| 82 | + */ | |
| 83 | + protected Bindings globalScope; | |
| 84 | + | |
| 85 | + | |
| 86 | + public SimpleScriptContext() { | |
| 87 | + engineScope = new SimpleBindings(); | |
| 88 | + globalScope = null; | |
| 89 | + reader = new InputStreamReader(System.in); | |
| 90 | + writer = new PrintWriter(System.out , true); | |
| 91 | + errorWriter = new PrintWriter(System.err, true); | |
| 92 | + } | |
| 93 | + | |
| 94 | + /** | |
| 95 | + * Sets a <code>Bindings</code> of attributes for the given scope. If the value | |
| 96 | + * of scope is <code>ENGINE_SCOPE</code> the given <code>Bindings</code> replaces the | |
| 97 | + * <code>engineScope</code> field. If the value | |
| 98 | + * of scope is <code>GLOBAL_SCOPE</code> the given <code>Bindings</code> replaces the | |
| 99 | + * <code>globalScope</code> field. | |
| 100 | + * | |
| 101 | + * @param bindings The <code>Bindings</code> of attributes to set. | |
| 102 | + * @param scope The value of the scope in which the attributes are set. | |
| 103 | + * | |
| 104 | + * @throws IllegalArgumentException if scope is invalid. | |
| 105 | + * @throws NullPointerException if the value of scope is <code>ENGINE_SCOPE</code> and | |
| 106 | + * the specified <code>Bindings</code> is null. | |
| 107 | + */ | |
| 108 | + public void setBindings(Bindings bindings, int scope) { | |
| 109 | + | |
| 110 | + switch (scope) { | |
| 111 | + | |
| 112 | + case ENGINE_SCOPE: | |
| 113 | + if (bindings == null) { | |
| 114 | + throw new NullPointerException("Engine scope cannot be null."); | |
| 115 | + } | |
| 116 | + engineScope = bindings; | |
| 117 | + break; | |
| 118 | + case GLOBAL_SCOPE: | |
| 119 | + globalScope = bindings; | |
| 120 | + break; | |
| 121 | + default: | |
| 122 | + throw new IllegalArgumentException("Invalid scope value."); | |
| 123 | + } | |
| 124 | + } | |
| 125 | + | |
| 126 | + | |
| 127 | + /** | |
| 128 | + * Retrieves the value of the attribute with the given name in | |
| 129 | + * the scope occurring earliest in the search order. The order | |
| 130 | + * is determined by the numeric value of the scope parameter (lowest | |
| 131 | + * scope values first.) | |
| 132 | + * | |
| 133 | + * @param name The name of the the attribute to retrieve. | |
| 134 | + * @return The value of the attribute in the lowest scope for | |
| 135 | + * which an attribute with the given name is defined. Returns | |
| 136 | + * null if no attribute with the name exists in any scope. | |
| 137 | + * @throws NullPointerException if the name is null. | |
| 138 | + * @throws IllegalArgumentException if the name is empty. | |
| 139 | + */ | |
| 140 | + public Object getAttribute(String name) { | |
| 141 | + if (engineScope.containsKey(name)) { | |
| 142 | + return getAttribute(name, ENGINE_SCOPE); | |
| 143 | + } else if (globalScope != null && globalScope.containsKey(name)) { | |
| 144 | + return getAttribute(name, GLOBAL_SCOPE); | |
| 145 | + } | |
| 146 | + | |
| 147 | + return null; | |
| 148 | + } | |
| 149 | + | |
| 150 | + /** | |
| 151 | + * Gets the value of an attribute in a given scope. | |
| 152 | + * | |
| 153 | + * @param name The name of the attribute to retrieve. | |
| 154 | + * @param scope The scope in which to retrieve the attribute. | |
| 155 | + * @return The value of the attribute. Returns <code>null</code> is the name | |
| 156 | + * does not exist in the given scope. | |
| 157 | + * | |
| 158 | + * @throws IllegalArgumentException | |
| 159 | + * if the name is empty or if the value of scope is invalid. | |
| 160 | + * @throws NullPointerException if the name is null. | |
| 161 | + */ | |
| 162 | + public Object getAttribute(String name, int scope) { | |
| 163 | + | |
| 164 | + switch (scope) { | |
| 165 | + | |
| 166 | + case ENGINE_SCOPE: | |
| 167 | + return engineScope.get(name); | |
| 168 | + | |
| 169 | + case GLOBAL_SCOPE: | |
| 170 | + if (globalScope != null) { | |
| 171 | + return globalScope.get(name); | |
| 172 | + } | |
| 173 | + return null; | |
| 174 | + | |
| 175 | + default: | |
| 176 | + throw new IllegalArgumentException("Illegal scope value."); | |
| 177 | + } | |
| 178 | + } | |
| 179 | + | |
| 180 | + /** | |
| 181 | + * Remove an attribute in a given scope. | |
| 182 | + * | |
| 183 | + * @param name The name of the attribute to remove | |
| 184 | + * @param scope The scope in which to remove the attribute | |
| 185 | + * | |
| 186 | + * @return The removed value. | |
| 187 | + * @throws IllegalArgumentException | |
| 188 | + * if the name is empty or if the scope is invalid. | |
| 189 | + * @throws NullPointerException if the name is null. | |
| 190 | + */ | |
| 191 | + public Object removeAttribute(String name, int scope) { | |
| 192 | + | |
| 193 | + switch (scope) { | |
| 194 | + | |
| 195 | + case ENGINE_SCOPE: | |
| 196 | + if (getBindings(ENGINE_SCOPE) != null) { | |
| 197 | + return getBindings(ENGINE_SCOPE).remove(name); | |
| 198 | + } | |
| 199 | + return null; | |
| 200 | + | |
| 201 | + case GLOBAL_SCOPE: | |
| 202 | + if (getBindings(GLOBAL_SCOPE) != null) { | |
| 203 | + return getBindings(GLOBAL_SCOPE).remove(name); | |
| 204 | + } | |
| 205 | + return null; | |
| 206 | + | |
| 207 | + default: | |
| 208 | + throw new IllegalArgumentException("Illegal scope value."); | |
| 209 | + } | |
| 210 | + } | |
| 211 | + | |
| 212 | + /** | |
| 213 | + * Sets the value of an attribute in a given scope. | |
| 214 | + * | |
| 215 | + * @param name The name of the attribute to set | |
| 216 | + * @param value The value of the attribute | |
| 217 | + * @param scope The scope in which to set the attribute | |
| 218 | + * | |
| 219 | + * @throws IllegalArgumentException | |
| 220 | + * if the name is empty or if the scope is invalid. | |
| 221 | + * @throws NullPointerException if the name is null. | |
| 222 | + */ | |
| 223 | + public void setAttribute(String name, Object value, int scope) { | |
| 224 | + | |
| 225 | + switch (scope) { | |
| 226 | + | |
| 227 | + case ENGINE_SCOPE: | |
| 228 | + engineScope.put(name, value); | |
| 229 | + return; | |
| 230 | + | |
| 231 | + case GLOBAL_SCOPE: | |
| 232 | + if (globalScope != null) { | |
| 233 | + globalScope.put(name, value); | |
| 234 | + } | |
| 235 | + return; | |
| 236 | + | |
| 237 | + default: | |
| 238 | + throw new IllegalArgumentException("Illegal scope value."); | |
| 239 | + } | |
| 240 | + } | |
| 241 | + | |
| 242 | + /** {@inheritDoc} */ | |
| 243 | + public Writer getWriter() { | |
| 244 | + return writer; | |
| 245 | + } | |
| 246 | + | |
| 247 | + /** {@inheritDoc} */ | |
| 248 | + public Reader getReader() { | |
| 249 | + return reader; | |
| 250 | + } | |
| 251 | + | |
| 252 | + /** {@inheritDoc} */ | |
| 253 | + public void setReader(Reader reader) { | |
| 254 | + this.reader = reader; | |
| 255 | + } | |
| 256 | + | |
| 257 | + /** {@inheritDoc} */ | |
| 258 | + public void setWriter(Writer writer) { | |
| 259 | + this.writer = writer; | |
| 260 | + } | |
| 261 | + | |
| 262 | + /** {@inheritDoc} */ | |
| 263 | + public Writer getErrorWriter() { | |
| 264 | + return errorWriter; | |
| 265 | + } | |
| 266 | + | |
| 267 | + /** {@inheritDoc} */ | |
| 268 | + public void setErrorWriter(Writer writer) { | |
| 269 | + this.errorWriter = writer; | |
| 270 | + } | |
| 271 | + | |
| 272 | + /** | |
| 273 | + * Get the lowest scope in which an attribute is defined. | |
| 274 | + * @param name Name of the attribute | |
| 275 | + * . | |
| 276 | + * @return The lowest scope. Returns -1 if no attribute with the given | |
| 277 | + * name is defined in any scope. | |
| 278 | + * @throws NullPointerException if name is null. | |
| 279 | + * @throws IllegalArgumentException if name is empty. | |
| 280 | + */ | |
| 281 | + public int getAttributesScope(String name) { | |
| 282 | + if (engineScope.containsKey(name)) { | |
| 283 | + return ENGINE_SCOPE; | |
| 284 | + } else if (globalScope != null && globalScope.containsKey(name)) { | |
| 285 | + return GLOBAL_SCOPE; | |
| 286 | + } else { | |
| 287 | + return -1; | |
| 288 | + } | |
| 289 | + } | |
| 290 | + | |
| 291 | + /** | |
| 292 | + * Returns the value of the <code>engineScope</code> field if specified scope is | |
| 293 | + * <code>ENGINE_SCOPE</code>. Returns the value of the <code>globalScope</code> field if the specified scope is | |
| 294 | + * <code>GLOBAL_SCOPE</code>. | |
| 295 | + * | |
| 296 | + * @param scope The specified scope | |
| 297 | + * @return The value of either the <code>engineScope</code> or <code>globalScope</code> field. | |
| 298 | + * @throws IllegalArgumentException if the value of scope is invalid. | |
| 299 | + */ | |
| 300 | + public Bindings getBindings(int scope) { | |
| 301 | + if (scope == ENGINE_SCOPE) { | |
| 302 | + return engineScope; | |
| 303 | + } else if (scope == GLOBAL_SCOPE) { | |
| 304 | + return globalScope; | |
| 305 | + } else { | |
| 306 | + throw new IllegalArgumentException("Illegal scope value."); | |
| 307 | + } | |
| 308 | + } | |
| 309 | + | |
| 310 | + /** {@inheritDoc} */ | |
| 311 | + public List<Integer> getScopes() { | |
| 312 | + return scopes; | |
| 313 | + } | |
| 314 | + | |
| 315 | + private static List<Integer> scopes; | |
| 316 | + static { | |
| 317 | + scopes = new ArrayList<Integer>(2); | |
| 318 | + scopes.add(ENGINE_SCOPE); | |
| 319 | + scopes.add(GLOBAL_SCOPE); | |
| 320 | + scopes = Collections.unmodifiableList(scopes); | |
| 321 | + } | |
| 322 | +} | |