| 1 | /******************************************************************************* |
|---|---|
| 2 | * Copyright (c) 2000, 2019 IBM Corporation and others. |
| 3 | * |
| 4 | * This program and the accompanying materials |
| 5 | * are made available under the terms of the Eclipse Public License 2.0 |
| 6 | * which accompanies this distribution, and is available at |
| 7 | * https://www.eclipse.org/legal/epl-2.0/ |
| 8 | * |
| 9 | * SPDX-License-Identifier: EPL-2.0 |
| 10 | * |
| 11 | * Contributors: |
| 12 | * IBM Corporation - initial API and implementation |
| 13 | *******************************************************************************/ |
| 14 | |
| 15 | package org.eclipse.jdt.core.dom; |
| 16 | |
| 17 | import java.util.ArrayList; |
| 18 | import java.util.List; |
| 19 | |
| 20 | /** |
| 21 | * Field access expression AST node type. |
| 22 | * |
| 23 | * <pre> |
| 24 | * FieldAccess: |
| 25 | * Expression <b>.</b> Identifier |
| 26 | * </pre> |
| 27 | * |
| 28 | * <p> |
| 29 | * Note that there are several kinds of expressions that resemble field access |
| 30 | * expressions: qualified names, this expressions, and super field access |
| 31 | * expressions. The following guidelines help with correct usage: |
| 32 | * </p> |
| 33 | * <ul> |
| 34 | * <li>An expression like "foo.this" can only be represented as a this |
| 35 | * expression (<code>ThisExpression</code>) containing a simple name. |
| 36 | * "this" is a keyword, and therefore invalid as an identifier.</li> |
| 37 | * <li>An expression like "this.foo" can only be represented as a field |
| 38 | * access expression (<code>FieldAccess</code>) containing a this expression |
| 39 | * and a simple name. Again, this is because "this" is a keyword, and |
| 40 | * therefore invalid as an identifier.</li> |
| 41 | * <li>An expression with "super" can only be represented as a super field |
| 42 | * access expression (<code>SuperFieldAccess</code>). "super" is a also |
| 43 | * keyword, and therefore invalid as an identifier.</li> |
| 44 | * <li>An expression like "foo.bar" can be represented either as a |
| 45 | * qualified name (<code>QualifiedName</code>) or as a field access |
| 46 | * expression (<code>FieldAccess</code>) containing simple names. Either |
| 47 | * is acceptable, and there is no way to choose between them without |
| 48 | * information about what the names resolve to |
| 49 | * (<code>ASTParser</code> may return either).</li> |
| 50 | * <li>Other expressions ending in an identifier, such as "foo().bar" can |
| 51 | * only be represented as field access expressions |
| 52 | * (<code>FieldAccess</code>).</li> |
| 53 | * </ul> |
| 54 | * |
| 55 | * @see QualifiedName |
| 56 | * @see ThisExpression |
| 57 | * @see SuperFieldAccess |
| 58 | * @since 2.0 |
| 59 | * @noinstantiate This class is not intended to be instantiated by clients. |
| 60 | */ |
| 61 | @SuppressWarnings("rawtypes") |
| 62 | public class FieldAccess extends Expression { |
| 63 | |
| 64 | /** |
| 65 | * The "expression" structural property of this node type (child type: {@link Expression}). |
| 66 | * @since 3.0 |
| 67 | */ |
| 68 | public static final ChildPropertyDescriptor EXPRESSION_PROPERTY = |
| 69 | new ChildPropertyDescriptor(FieldAccess.class, "expression", Expression.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$ |
| 70 | |
| 71 | /** |
| 72 | * The "name" structural property of this node type (child type: {@link SimpleName}). |
| 73 | * @since 3.0 |
| 74 | */ |
| 75 | public static final ChildPropertyDescriptor NAME_PROPERTY = |
| 76 | new ChildPropertyDescriptor(FieldAccess.class, "name", SimpleName.class, MANDATORY, NO_CYCLE_RISK); //$NON-NLS-1$ |
| 77 | |
| 78 | /** |
| 79 | * A list of property descriptors (element type: |
| 80 | * {@link StructuralPropertyDescriptor}), |
| 81 | * or null if uninitialized. |
| 82 | */ |
| 83 | private static final List PROPERTY_DESCRIPTORS; |
| 84 | |
| 85 | static { |
| 86 | List properyList = new ArrayList(3); |
| 87 | createPropertyList(FieldAccess.class, properyList); |
| 88 | addProperty(EXPRESSION_PROPERTY, properyList); |
| 89 | addProperty(NAME_PROPERTY, properyList); |
| 90 | PROPERTY_DESCRIPTORS = reapPropertyList(properyList); |
| 91 | } |
| 92 | |
| 93 | /** |
| 94 | * Returns a list of structural property descriptors for this node type. |
| 95 | * Clients must not modify the result. |
| 96 | * |
| 97 | * @param apiLevel the API level; one of the |
| 98 | * <code>AST.JLS*</code> constants |
| 99 | |
| 100 | * @return a list of property descriptors (element type: |
| 101 | * {@link StructuralPropertyDescriptor}) |
| 102 | * @since 3.0 |
| 103 | */ |
| 104 | public static List propertyDescriptors(int apiLevel) { |
| 105 | return PROPERTY_DESCRIPTORS; |
| 106 | } |
| 107 | |
| 108 | /** |
| 109 | * The expression; lazily initialized; defaults to an unspecified, |
| 110 | * but legal, simple name. |
| 111 | */ |
| 112 | private Expression expression = null; |
| 113 | |
| 114 | /** |
| 115 | * The field; lazily initialized; defaults to an unspecified, |
| 116 | * but legal, simple field name. |
| 117 | */ |
| 118 | private SimpleName fieldName = null; |
| 119 | |
| 120 | /** |
| 121 | * Creates a new unparented node for a field access expression owned by the |
| 122 | * given AST. By default, the expression and field are both unspecified, |
| 123 | * but legal, names. |
| 124 | * <p> |
| 125 | * N.B. This constructor is package-private. |
| 126 | * </p> |
| 127 | * |
| 128 | * @param ast the AST that is to own this node |
| 129 | */ |
| 130 | FieldAccess(AST ast) { |
| 131 | super(ast); |
| 132 | } |
| 133 | |
| 134 | @Override |
| 135 | final List internalStructuralPropertiesForType(int apiLevel) { |
| 136 | return propertyDescriptors(apiLevel); |
| 137 | } |
| 138 | |
| 139 | @Override |
| 140 | final ASTNode internalGetSetChildProperty(ChildPropertyDescriptor property, boolean get, ASTNode child) { |
| 141 | if (property == EXPRESSION_PROPERTY) { |
| 142 | if (get) { |
| 143 | return getExpression(); |
| 144 | } else { |
| 145 | setExpression((Expression) child); |
| 146 | return null; |
| 147 | } |
| 148 | } |
| 149 | if (property == NAME_PROPERTY) { |
| 150 | if (get) { |
| 151 | return getName(); |
| 152 | } else { |
| 153 | setName((SimpleName) child); |
| 154 | return null; |
| 155 | } |
| 156 | } |
| 157 | // allow default implementation to flag the error |
| 158 | return super.internalGetSetChildProperty(property, get, child); |
| 159 | } |
| 160 | |
| 161 | @Override |
| 162 | final int getNodeType0() { |
| 163 | return FIELD_ACCESS; |
| 164 | } |
| 165 | |
| 166 | @Override |
| 167 | ASTNode clone0(AST target) { |
| 168 | FieldAccess result = new FieldAccess(target); |
| 169 | result.setSourceRange(getStartPosition(), getLength()); |
| 170 | result.setExpression((Expression) getExpression().clone(target)); |
| 171 | result.setName((SimpleName) getName().clone(target)); |
| 172 | return result; |
| 173 | } |
| 174 | |
| 175 | @Override |
| 176 | final boolean subtreeMatch0(ASTMatcher matcher, Object other) { |
| 177 | // dispatch to correct overloaded match method |
| 178 | return matcher.match(this, other); |
| 179 | } |
| 180 | |
| 181 | @Override |
| 182 | void accept0(ASTVisitor visitor) { |
| 183 | boolean visitChildren = visitor.visit(this); |
| 184 | if (visitChildren) { |
| 185 | // visit children in normal left to right reading order |
| 186 | acceptChild(visitor, getExpression()); |
| 187 | acceptChild(visitor, getName()); |
| 188 | } |
| 189 | visitor.endVisit(this); |
| 190 | } |
| 191 | |
| 192 | /** |
| 193 | * Returns the expression of this field access expression. |
| 194 | * |
| 195 | * @return the expression node |
| 196 | */ |
| 197 | public Expression getExpression() { |
| 198 | if (this.expression == null) { |
| 199 | // lazy init must be thread-safe for readers |
| 200 | synchronized (this) { |
| 201 | if (this.expression == null) { |
| 202 | preLazyInit(); |
| 203 | this.expression = new SimpleName(this.ast); |
| 204 | postLazyInit(this.expression, EXPRESSION_PROPERTY); |
| 205 | } |
| 206 | } |
| 207 | } |
| 208 | return this.expression; |
| 209 | } |
| 210 | |
| 211 | /** |
| 212 | * Sets the expression of this field access expression. |
| 213 | * |
| 214 | * @param expression the new expression |
| 215 | * @exception IllegalArgumentException if: |
| 216 | * <ul> |
| 217 | * <li>the node belongs to a different AST</li> |
| 218 | * <li>the node already has a parent</li> |
| 219 | * <li>a cycle in would be created</li> |
| 220 | * </ul> |
| 221 | */ |
| 222 | public void setExpression(Expression expression) { |
| 223 | if (expression == null) { |
| 224 | throw new IllegalArgumentException(); |
| 225 | } |
| 226 | ASTNode oldChild = this.expression; |
| 227 | preReplaceChild(oldChild, expression, EXPRESSION_PROPERTY); |
| 228 | this.expression = expression; |
| 229 | postReplaceChild(oldChild, expression, EXPRESSION_PROPERTY); |
| 230 | } |
| 231 | |
| 232 | /** |
| 233 | * Returns the name of the field accessed in this field access expression. |
| 234 | * |
| 235 | * @return the field name |
| 236 | */ |
| 237 | public SimpleName getName() { |
| 238 | if (this.fieldName == null) { |
| 239 | // lazy init must be thread-safe for readers |
| 240 | synchronized (this) { |
| 241 | if (this.fieldName == null) { |
| 242 | preLazyInit(); |
| 243 | this.fieldName = new SimpleName(this.ast); |
| 244 | postLazyInit(this.fieldName, NAME_PROPERTY); |
| 245 | } |
| 246 | } |
| 247 | } |
| 248 | return this.fieldName; |
| 249 | } |
| 250 | |
| 251 | /** |
| 252 | * Sets the name of the field accessed in this field access expression. |
| 253 | * |
| 254 | * @param fieldName the field name |
| 255 | * @exception IllegalArgumentException if: |
| 256 | * <ul> |
| 257 | * <li>the node belongs to a different AST</li> |
| 258 | * <li>the node already has a parent</li> |
| 259 | * </ul> |
| 260 | */ |
| 261 | public void setName(SimpleName fieldName) { |
| 262 | if (fieldName == null) { |
| 263 | throw new IllegalArgumentException(); |
| 264 | } |
| 265 | ASTNode oldChild = this.fieldName; |
| 266 | preReplaceChild(oldChild, fieldName, NAME_PROPERTY); |
| 267 | this.fieldName = fieldName; |
| 268 | postReplaceChild(oldChild, fieldName, NAME_PROPERTY); |
| 269 | } |
| 270 | |
| 271 | @Override |
| 272 | int memSize() { |
| 273 | // treat Code as free |
| 274 | return BASE_NODE_SIZE + 2 * 4; |
| 275 | } |
| 276 | |
| 277 | /** |
| 278 | * Resolves and returns the binding for the field accessed by this |
| 279 | * expression. |
| 280 | * <p> |
| 281 | * Note that bindings are generally unavailable unless requested when the |
| 282 | * AST is being built. |
| 283 | * </p> |
| 284 | * |
| 285 | * @return the variable binding, or <code>null</code> if the binding cannot |
| 286 | * be resolved |
| 287 | * @since 3.0 |
| 288 | */ |
| 289 | public IVariableBinding resolveFieldBinding() { |
| 290 | return this.ast.getBindingResolver().resolveField(this); |
| 291 | } |
| 292 | |
| 293 | @Override |
| 294 | int treeSize() { |
| 295 | return |
| 296 | memSize() |
| 297 | + (this.expression == null ? 0 : getExpression().treeSize()) |
| 298 | + (this.fieldName == null ? 0 : getName().treeSize()); |
| 299 | } |
| 300 | } |
| 301 | |
| 302 |
Members