net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/core/dom/InfixExpression.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2008 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Eclipse Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/epl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11
  12 package net.sourceforge.phpdt.core.dom;
  13
  14 import java.util.ArrayList;
  15 import java.util.HashMap;
  16 import java.util.List;
  17 import java.util.Map;
  18
  19 /**
  20  * Infix expression AST node type.
  21  * <pre>
  22  * InfixExpression:
  23  *    Expression InfixOperator Expression { InfixOperator Expression }
  24  * </pre>
  25  *
  26  * @since 2.0
  27  * @noinstantiate This class is not intended to be instantiated by clients.
  28  */
  29 public class InfixExpression extends Expression {
  30
  31         /**
  32          * Infix operators (typesafe enumeration).
  33          * <pre>
  34          * InfixOperator:<code>
  35          *    <b>*</b>  TIMES
  36          *    <b>/</b>  DIVIDE
  37          *    <b>%</b>  REMAINDER
  38          *    <b>+</b>  PLUS
  39          *    <b>-</b>  MINUS
  40          *    <b>&lt;&lt;</b>  LEFT_SHIFT
  41          *    <b>&gt;&gt;</b>  RIGHT_SHIFT_SIGNED
  42          *    <b>&gt;&gt;&gt;</b>  RIGHT_SHIFT_UNSIGNED
  43          *    <b>&lt;</b>  LESS
  44          *    <b>&gt;</b>  GREATER
  45          *    <b>&lt;=</b>  LESS_EQUALS
  46          *    <b>&gt;=</b>  GREATER_EQUALS
  47          *    <b>==</b>  EQUALS
  48          *    <b>!=</b>  NOT_EQUALS
  49          *    <b>^</b>  XOR
  50          *    <b>&amp;</b>  AND
  51          *    <b>|</b>  OR
  52          *    <b>&amp;&amp;</b>  CONDITIONAL_AND
  53          *    <b>||</b>  CONDITIONAL_OR</code>
  54          * </pre>
  55          */
  56         public static class Operator {
  57
  58                 /**
  59                  * The token for the operator.
  60                  */
  61                 private String token;
  62
  63                 /**
  64                  * Creates a new infix operator with the given token.
  65                  * <p>
  66                  * Note: this constructor is private. The only instances
  67                  * ever created are the ones for the standard operators.
  68                  * </p>
  69                  *
  70                  * @param token the character sequence for the operator
  71                  */
  72                 private Operator(String token) {
  73                         this.token = token;
  74                 }
  75
  76                 /**
  77                  * Returns the character sequence for the operator.
  78                  *
  79                  * @return the character sequence for the operator
  80                  */
  81                 public String toString() {
  82                         return token;
  83                 }
  84
  85                 /** Multiplication "*" operator. */
  86                 public static final Operator TIMES = new Operator("*");//$NON-NLS-1$
  87                 /** Division "/" operator. */
  88                 public static final Operator DIVIDE = new Operator("/");//$NON-NLS-1$
  89                 /** Remainder "%" operator. */
  90                 public static final Operator REMAINDER = new Operator("%");//$NON-NLS-1$
  91                 /** Addition (or string concatenation) "+" operator. */
  92                 public static final Operator PLUS = new Operator("+");//$NON-NLS-1$
  93                 /** Subtraction "-" operator. */
  94                 public static final Operator MINUS = new Operator("-");//$NON-NLS-1$
  95                 /** Left shift "&lt;&lt;" operator. */
  96                 public static final Operator LEFT_SHIFT = new Operator("<<");//$NON-NLS-1$
  97                 /** Signed right shift "&gt;&gt;" operator. */
  98                 public static final Operator RIGHT_SHIFT_SIGNED = new Operator(">>");//$NON-NLS-1$
  99                 /** Unsigned right shift "&gt;&gt;&gt;" operator. */
 100                 public static final Operator RIGHT_SHIFT_UNSIGNED =
 101                         new Operator(">>>");//$NON-NLS-1$
 102                 /** Less than "&lt;" operator. */
 103                 public static final Operator LESS = new Operator("<");//$NON-NLS-1$
 104                 /** Greater than "&gt;" operator. */
 105                 public static final Operator GREATER = new Operator(">");//$NON-NLS-1$
 106                 /** Less than or equals "&lt;=" operator. */
 107                 public static final Operator LESS_EQUALS = new Operator("<=");//$NON-NLS-1$
 108                 /** Greater than or equals "&gt=;" operator. */
 109                 public static final Operator GREATER_EQUALS = new Operator(">=");//$NON-NLS-1$
 110                 /** Equals "==" operator. */
 111                 public static final Operator EQUALS = new Operator("==");//$NON-NLS-1$
 112                 /** Not equals "!=" operator. */
 113                 public static final Operator NOT_EQUALS = new Operator("!=");//$NON-NLS-1$
 114                 /** Exclusive OR "^" operator. */
 115                 public static final Operator XOR = new Operator("^");//$NON-NLS-1$
 116                 /** Inclusive OR "|" operator. */
 117                 public static final Operator OR = new Operator("|");//$NON-NLS-1$
 118                 /** AND "&amp;" operator. */
 119                 public static final Operator AND = new Operator("&");//$NON-NLS-1$
 120                 /** Conditional OR "||" operator. */
 121                 public static final Operator CONDITIONAL_OR = new Operator("||");//$NON-NLS-1$
 122                 /** Conditional AND "&amp;&amp;" operator. */
 123                 public static final Operator CONDITIONAL_AND = new Operator("&&");//$NON-NLS-1$
 124
 125                 /**
 126                  * Map from token to operator (key type: <code>String</code>;
 127                  * value type: <code>Operator</code>).
 128                  */
 129                 private static final Map CODES;
 130                 static {
 131                         CODES = new HashMap(20);
 132                         Operator[] ops = {
 133                                         TIMES,
 134                                         DIVIDE,
 135                                         REMAINDER,
 136                                         PLUS,
 137                                         MINUS,
 138                                         LEFT_SHIFT,
 139                                         RIGHT_SHIFT_SIGNED,
 140                                         RIGHT_SHIFT_UNSIGNED,
 141                                         LESS,
 142                                         GREATER,
 143                                         LESS_EQUALS,
 144                                         GREATER_EQUALS,
 145                                         EQUALS,
 146                                         NOT_EQUALS,
 147                                         XOR,
 148                                         OR,
 149                                         AND,
 150                                         CONDITIONAL_OR,
 151                                         CONDITIONAL_AND,
 152                                 };
 153                         for (int i = 0; i < ops.length; i++) {
 154                                 CODES.put(ops[i].toString(), ops[i]);
 155                         }
 156                 }
 157
 158                 /**
 159                  * Returns the infix operator corresponding to the given string,
 160                  * or <code>null</code> if none.
 161                  * <p>
 162                  * <code>toOperator</code> is the converse of <code>toString</code>:
 163                  * that is, <code>Operator.toOperator(op.toString()) == op</code> for
 164                  * all operators <code>op</code>.
 165                  * </p>
 166                  *
 167                  * @param token the character sequence for the operator
 168                  * @return the infix operator, or <code>null</code> if none
 169                  */
 170                 public static Operator toOperator(String token) {
 171                         return (Operator) CODES.get(token);
 172                 }
 173
 174         }
 175
 176         /**
 177          * The "leftOperand" structural property of this node type.
 178          * @since 3.0
 179          */
 180         public static final ChildPropertyDescriptor LEFT_OPERAND_PROPERTY =
 181                 new ChildPropertyDescriptor(InfixExpression.class, "leftOperand", Expression.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$
 182
 183         /**
 184          * The "operator" structural property of this node type.
 185          * @since 3.0
 186          */
 187         public static final SimplePropertyDescriptor OPERATOR_PROPERTY =
 188                 new SimplePropertyDescriptor(InfixExpression.class, "operator", InfixExpression.Operator.class, MANDATORY); //$NON-NLS-1$
 189
 190         /**
 191          * The "rightOperand" structural property of this node type.
 192          * @since 3.0
 193          */
 194         public static final ChildPropertyDescriptor RIGHT_OPERAND_PROPERTY =
 195                 new ChildPropertyDescriptor(InfixExpression.class, "rightOperand", Expression.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$
 196
 197         /**
 198          * The "extendedOperands" structural property of this node type.
 199          * @since 3.0
 200          */
 201         public static final ChildListPropertyDescriptor EXTENDED_OPERANDS_PROPERTY =
 202                 new ChildListPropertyDescriptor(InfixExpression.class, "extendedOperands", Expression.class, CYCLE_RISK); //$NON-NLS-1$
 203
 204         /**
 205          * A list of property descriptors (element type:
 206          * {@link StructuralPropertyDescriptor}),
 207          * or null if uninitialized.
 208          */
 209         private static final List PROPERTY_DESCRIPTORS;
 210
 211         static {
 212                 List properyList = new ArrayList(5);
 213                 createPropertyList(InfixExpression.class, properyList);
 214                 addProperty(LEFT_OPERAND_PROPERTY, properyList);
 215                 addProperty(OPERATOR_PROPERTY, properyList);
 216                 addProperty(RIGHT_OPERAND_PROPERTY, properyList);
 217                 addProperty(EXTENDED_OPERANDS_PROPERTY, properyList);
 218                 PROPERTY_DESCRIPTORS = reapPropertyList(properyList);
 219         }
 220
 221         /**
 222          * Returns a list of structural property descriptors for this node type.
 223          * Clients must not modify the result.
 224          *
 225          * @param apiLevel the API level; one of the
 226          * <code>AST.JLS*</code> constants
 227
 228          * @return a list of property descriptors (element type:
 229          * {@link StructuralPropertyDescriptor})
 230          * @since 3.0
 231          */
 232         public static List propertyDescriptors(int apiLevel) {
 233                 return PROPERTY_DESCRIPTORS;
 234         }
 235
 236         /**
 237          * The infix operator; defaults to InfixExpression.Operator.PLUS.
 238          */
 239         private InfixExpression.Operator operator = InfixExpression.Operator.PLUS;
 240
 241         /**
 242          * The left operand; lazily initialized; defaults to an unspecified,
 243          * but legal, simple name.
 244          */
 245         private Expression leftOperand = null;
 246
 247         /**
 248          * The right operand; lazily initialized; defaults to an unspecified,
 249          * but legal, simple name.
 250          */
 251         private Expression rightOperand = null;
 252
 253         /**
 254          * The list of extended operand expressions (element type:
 255          * <code>Expression</code>). Lazily initialized; defaults to an empty list.
 256          */
 257         private ASTNode.NodeList extendedOperands = null;
 258
 259         /**
 260          * Creates a new AST node for an infix expression owned by the given
 261          * AST. By default, the node has unspecified (but legal) operator,
 262          * left and right operands, and an empty list of additional operands.
 263          *
 264          * @param ast the AST that is to own this node
 265          */
 266         InfixExpression(AST ast) {
 267                 super(ast);
 268         }
 269
 270         /* (omit javadoc for this method)
 271          * Method declared on ASTNode.
 272          */
 273         final List internalStructuralPropertiesForType(int apiLevel) {
 274                 return propertyDescriptors(apiLevel);
 275         }
 276
 277         /* (omit javadoc for this method)
 278          * Method declared on ASTNode.
 279          */
 280         final Object internalGetSetObjectProperty(SimplePropertyDescriptor property, boolean get, Object value) {
 281                 if (property == OPERATOR_PROPERTY) {
 282                         if (get) {
 283                                 return getOperator();
 284                         } else {
 285                                 setOperator((Operator) value);
 286                                 return null;
 287                         }
 288                 }
 289                 // allow default implementation to flag the error
 290                 return super.internalGetSetObjectProperty(property, get, value);
 291         }
 292
 293         /* (omit javadoc for this method)
 294          * Method declared on ASTNode.
 295          */
 296         final ASTNode internalGetSetChildProperty(ChildPropertyDescriptor property, boolean get, ASTNode child) {
 297                 if (property == LEFT_OPERAND_PROPERTY) {
 298                         if (get) {
 299                                 return getLeftOperand();
 300                         } else {
 301                                 setLeftOperand((Expression) child);
 302                                 return null;
 303                         }
 304                 }
 305                 if (property == RIGHT_OPERAND_PROPERTY) {
 306                         if (get) {
 307                                 return getRightOperand();
 308                         } else {
 309                                 setRightOperand((Expression) child);
 310                                 return null;
 311                         }
 312                 }
 313                 // allow default implementation to flag the error
 314                 return super.internalGetSetChildProperty(property, get, child);
 315         }
 316
 317         /* (omit javadoc for this method)
 318          * Method declared on ASTNode.
 319          */
 320         final List internalGetChildListProperty(ChildListPropertyDescriptor property) {
 321                 if (property == EXTENDED_OPERANDS_PROPERTY) {
 322                         return extendedOperands();
 323                 }
 324                 // allow default implementation to flag the error
 325                 return super.internalGetChildListProperty(property);
 326         }
 327
 328         /* (omit javadoc for this method)
 329          * Method declared on ASTNode.
 330          */
 331         final int getNodeType0() {
 332                 return INFIX_EXPRESSION;
 333         }
 334
 335         /* (omit javadoc for this method)
 336          * Method declared on ASTNode.
 337          */
 338         ASTNode clone0(AST target) {
 339                 InfixExpression result = new InfixExpression(target);
 340                 result.setSourceRange(this.getStartPosition(), this.getLength());
 341                 result.setOperator(getOperator());
 342                 result.setLeftOperand((Expression) getLeftOperand().clone(target));
 343                 result.setRightOperand((Expression) getRightOperand().clone(target));
 344                 if (this.extendedOperands != null) {
 345                         // be careful not to trigger lazy creation of list
 346                         result.extendedOperands().addAll(
 347                                 ASTNode.copySubtrees(target, this.extendedOperands()));
 348                 }
 349                 return result;
 350         }
 351
 352         /* (omit javadoc for this method)
 353          * Method declared on ASTNode.
 354          */
 355         final boolean subtreeMatch0(ASTMatcher matcher, Object other) {
 356                 // dispatch to correct overloaded match method
 357                 return matcher.match(this, other);
 358         }
 359
 360         /* (omit javadoc for this method)
 361          * Method declared on ASTNode.
 362          */
 363         void accept0(ASTVisitor visitor) {
 364                 boolean visitChildren = visitor.visit(this);
 365                 if (visitChildren) {
 366                         // visit children in normal left to right reading order
 367                         acceptChild(visitor, getLeftOperand());
 368                         acceptChild(visitor, getRightOperand());
 369                         if (this.extendedOperands != null) {
 370                                 // be careful not to trigger lazy creation of list
 371                                 acceptChildren(visitor, this.extendedOperands);
 372                         }
 373                 }
 374                 visitor.endVisit(this);
 375         }
 376
 377         /**
 378          * Returns the operator of this infix expression.
 379          *
 380          * @return the infix operator
 381          */
 382         public InfixExpression.Operator getOperator() {
 383                 return this.operator;
 384         }
 385
 386         /**
 387          * Sets the operator of this infix expression.
 388          *
 389          * @param operator the infix operator
 390          * @exception IllegalArgumentException if the argument is incorrect
 391          */
 392         public void setOperator(InfixExpression.Operator operator) {
 393                 if (operator == null) {
 394                         throw new IllegalArgumentException();
 395                 }
 396                 preValueChange(OPERATOR_PROPERTY);
 397                 this.operator = operator;
 398                 postValueChange(OPERATOR_PROPERTY);
 399         }
 400
 401         /**
 402          * Returns the left operand of this infix expression.
 403          *
 404          * @return the left operand node
 405          */
 406         public Expression getLeftOperand() {
 407                 if (this.leftOperand  == null) {
 408                         // lazy init must be thread-safe for readers
 409                         synchronized (this) {
 410                                 if (this.leftOperand == null) {
 411                                         preLazyInit();
 412                                         this.leftOperand= new SimpleName(this.ast);
 413                                         postLazyInit(this.leftOperand, LEFT_OPERAND_PROPERTY);
 414                                 }
 415                         }
 416                 }
 417                 return this.leftOperand;
 418         }
 419
 420         /**
 421          * Sets the left operand of this infix expression.
 422          *
 423          * @param expression the left operand node
 424          * @exception IllegalArgumentException if:
 425          * <ul>
 426          * <li>the node belongs to a different AST</li>
 427          * <li>the node already has a parent</li>
 428          * <li>a cycle in would be created</li>
 429          * </ul>
 430          */
 431         public void setLeftOperand(Expression expression) {
 432                 if (expression == null) {
 433                         throw new IllegalArgumentException();
 434                 }
 435                 ASTNode oldChild = this.leftOperand;
 436                 preReplaceChild(oldChild, expression, LEFT_OPERAND_PROPERTY);
 437                 this.leftOperand = expression;
 438                 postReplaceChild(oldChild, expression, LEFT_OPERAND_PROPERTY);
 439         }
 440
 441         /**
 442          * Returns the right operand of this infix expression.
 443          *
 444          * @return the right operand node
 445          */
 446         public Expression getRightOperand() {
 447                 if (this.rightOperand  == null) {
 448                         // lazy init must be thread-safe for readers
 449                         synchronized (this) {
 450                                 if (this.rightOperand  == null) {
 451                                         preLazyInit();
 452                                         this.rightOperand= new SimpleName(this.ast);
 453                                         postLazyInit(this.rightOperand, RIGHT_OPERAND_PROPERTY);
 454                                 }
 455                         }
 456                 }
 457                 return this.rightOperand;
 458         }
 459
 460         /**
 461          * Sets the right operand of this infix expression.
 462          *
 463          * @param expression the right operand node
 464          * @exception IllegalArgumentException if:
 465          * <ul>
 466          * <li>the node belongs to a different AST</li>
 467          * <li>the node already has a parent</li>
 468          * <li>a cycle in would be created</li>
 469          * </ul>
 470          */
 471         public void setRightOperand(Expression expression) {
 472                 if (expression == null) {
 473                         throw new IllegalArgumentException();
 474                 }
 475                 ASTNode oldChild = this.rightOperand;
 476                 preReplaceChild(oldChild, expression, RIGHT_OPERAND_PROPERTY);
 477                 this.rightOperand = expression;
 478                 postReplaceChild(oldChild, expression, RIGHT_OPERAND_PROPERTY);
 479         }
 480
 481         /**
 482          * Returns where there are any extended operands.
 483          *
 484          * @return <code>true</code> if there are one or more extended operands,
 485          *    and <code>false</code> if there are no extended operands
 486          */
 487         public boolean hasExtendedOperands() {
 488                 return
 489                         (this.extendedOperands != null) && this.extendedOperands.size() > 0;
 490         }
 491
 492         /**
 493          * Returns the live list of extended operands.
 494          * <p>
 495          * The extended operands is the preferred way of representing deeply nested
 496          * expressions of the form <code>L op R op R2 op R3...</code> where
 497          * the same operator appears between all the operands (the most
 498          * common case being lengthy string concatenation expressions). Using
 499          * the extended operands keeps the trees from getting too deep; this
 500          * decreases the risk is running out of thread stack space at runtime
 501          * when traversing such trees.
 502          * ((a + b) + c) + d would be translated to:
 503          *      leftOperand: a
 504          *      rightOperand: b
 505          *      extendedOperands: {c, d}
 506          *      operator: +
 507          * </p>
 508          *
 509          * @return the live list of extended operands
 510          *   (element type: <code>Expression</code>)
 511          */
 512         public List extendedOperands() {
 513                 if (this.extendedOperands == null) {
 514                         // lazily initialize
 515                         this.extendedOperands = new ASTNode.NodeList(EXTENDED_OPERANDS_PROPERTY);
 516                 }
 517                 return this.extendedOperands;
 518         }
 519
 520         /* (omit javadoc for this method)
 521          * Method declared on ASTNode.
 522          */
 523         int memSize() {
 524                 // treat Operator as free
 525                 return BASE_NODE_SIZE + 4 * 4;
 526         }
 527
 528         /* (omit javadoc for this method)
 529          * Method declared on ASTNode.
 530          */
 531         int treeSize() {
 532                 return
 533                         memSize()
 534                         + (this.leftOperand == null ? 0 : getLeftOperand().treeSize())
 535                         + (this.rightOperand == null ? 0 : getRightOperand().treeSize())
 536                         + (this.extendedOperands == null ? 0 : extendedOperands.listSize());
 537         }
 538 }