Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2019 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.jdt.core.dom; import java.util.ArrayList; import java.util.List; /** * Switch statement AST node type. * <pre> * SwitchStatement: * <b>switch</b> <b>(</b> Expression <b>)</b> * <b>{</b> { SwitchCase | Statement } <b>}</b> * SwitchCase: * <b>case</b> Expression <b>:</b> * <b>default</b> <b>:</b> * </pre> * <code>SwitchCase</code> nodes are treated as a kind of * <code>Statement</code>. * * @since 2.0 * @noinstantiate This class is not intended to be instantiated by clients. */ @SuppressWarnings({ "rawtypes", "unchecked" }) public class SwitchStatement extends Statement { /** * The "expression" structural property of this node type (child type: {@link Expression}). * @since 3.0 */ public static final ChildPropertyDescriptor EXPRESSION_PROPERTY = new ChildPropertyDescriptor( SwitchStatement.class, "expression", Expression.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$ /** * The "statements" structural property of this node type (element type: {@link Statement}). * @since 3.0 */ public static final ChildListPropertyDescriptor STATEMENTS_PROPERTY = new ChildListPropertyDescriptor( SwitchStatement.class, "statements", Statement.class, CYCLE_RISK); //$NON-NLS-1$ /** * A list of property descriptors (element type: * {@link StructuralPropertyDescriptor}), * or null if uninitialized. */ private static final List PROPERTY_DESCRIPTORS; static { List propertyList = new ArrayList(3); createPropertyList(SwitchStatement.class, propertyList); addProperty(EXPRESSION_PROPERTY, propertyList); addProperty(STATEMENTS_PROPERTY, propertyList); PROPERTY_DESCRIPTORS = reapPropertyList(propertyList); } /** * Returns a list of structural property descriptors for this node type. * Clients must not modify the result. * * @param apiLevel the API level; one of the * <code>AST.JLS*</code> constants * @return a list of property descriptors (element type: * {@link StructuralPropertyDescriptor}) * @since 3.0 */ public static List propertyDescriptors(int apiLevel) { return PROPERTY_DESCRIPTORS; } /** * The expression; lazily initialized; defaults to a unspecified, but legal, * expression. */ private Expression expression = null; /** * The statements and SwitchCase nodes * (element type: {@link Statement}). * Defaults to an empty list. */ private ASTNode.NodeList statements = new ASTNode.NodeList(STATEMENTS_PROPERTY); /** * Creates a new unparented switch statement node owned by the given * AST. By default, the swicth statement has an unspecified, but legal, * expression, and an empty list of switch groups. * <p> * N.B. This constructor is package-private. * </p> * * @param ast the AST that is to own this node */ SwitchStatement(AST ast) { super(ast); } @Override final List internalStructuralPropertiesForType(int apiLevel) { return propertyDescriptors(apiLevel); } @Override final ASTNode internalGetSetChildProperty(ChildPropertyDescriptor property, boolean get, ASTNode child) { if (property == EXPRESSION_PROPERTY) { if (get) { return getExpression(); } else { setExpression((Expression) child); return null; } } // allow default implementation to flag the error return super.internalGetSetChildProperty(property, get, child); } @Override final List internalGetChildListProperty(ChildListPropertyDescriptor property) { if (property == STATEMENTS_PROPERTY) { return statements(); } // allow default implementation to flag the error return super.internalGetChildListProperty(property); } @Override final int getNodeType0() { return SWITCH_STATEMENT; } @Override ASTNode clone0(AST target) { SwitchStatement result = new SwitchStatement(target); result.setSourceRange(getStartPosition(), getLength()); result.copyLeadingComment(this); result.setExpression((Expression) getExpression().clone(target)); result.statements().addAll(ASTNode.copySubtrees(target, statements())); return result; } @Override final boolean subtreeMatch0(ASTMatcher matcher, Object other) { // dispatch to correct overloaded match method return matcher.match(this, other); } @Override void accept0(ASTVisitor visitor) { boolean visitChildren = visitor.visit(this); if (visitChildren) { // visit children in normal left to right reading order acceptChild(visitor, getExpression()); acceptChildren(visitor, this.statements); } visitor.endVisit(this); } /** * Returns the expression of this switch statement. * * @return the expression node */ public Expression getExpression() { if (this.expression == null) { // lazy init must be thread-safe for readers synchronized (this) { if (this.expression == null) { preLazyInit(); this.expression = new SimpleName(this.ast); postLazyInit(this.expression, EXPRESSION_PROPERTY); } } } return this.expression; } /** * Sets the expression of this switch statement. * * @param expression the new expression node * @exception IllegalArgumentException if: * <ul> * <li>the node belongs to a different AST</li> * <li>the node already has a parent</li> * <li>a cycle in would be created</li> * </ul> */ public void setExpression(Expression expression) { if (expression == null) { throw new IllegalArgumentException(); } ASTNode oldChild = this.expression; preReplaceChild(oldChild, expression, EXPRESSION_PROPERTY); this.expression = expression; postReplaceChild(oldChild, expression, EXPRESSION_PROPERTY); } /** * Returns the live ordered list of statements for this switch statement. * Within this list, <code>SwitchCase</code> nodes mark the start of * the switch groups. * * @return the live list of statement nodes * (element type: {@link Statement}) */ public List statements() { return this.statements; } @Override int memSize() { return super.memSize() + 2 * 4; } @Override int treeSize() { return memSize() + (this.expression == null ? 0 : getExpression().treeSize()) + this.statements.listSize(); } }