Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2013 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; /** * For statement AST node type. * * <pre> * ForStatement: * <b>for</b> <b>(</b> * [ ForInit ]<b>;</b> * [ Expression ] <b>;</b> * [ ForUpdate ] <b>)</b> * Statement * ForInit: * Expression { <b>,</b> Expression } * ForUpdate: * Expression { <b>,</b> Expression } * </pre> * <p> * Note: When variables are declared in the initializer * of a for statement such as "<code>for (int a=1, b=2;;);</code>", * they should be represented as a single * <code>VariableDeclarationExpression</code> * with two fragments, rather than being split up into a pair * of expressions. * </p> * * @since 2.0 * @noinstantiate This class is not intended to be instantiated by clients. */ @SuppressWarnings({ "rawtypes", "unchecked" }) public class ForStatement extends Statement { /** * The "initializers" structural property of this node type (element type: {@link Expression}). * @since 3.0 */ public static final ChildListPropertyDescriptor INITIALIZERS_PROPERTY = new ChildListPropertyDescriptor( ForStatement.class, "initializers", Expression.class, CYCLE_RISK); //$NON-NLS-1$ /** * The "expression" structural property of this node type (child type: {@link Expression}). * @since 3.0 */ public static final ChildPropertyDescriptor EXPRESSION_PROPERTY = new ChildPropertyDescriptor( ForStatement.class, "expression", Expression.class, OPTIONAL, CYCLE_RISK); //$NON-NLS-1$ /** * The "updaters" structural property of this node type (element type: {@link Expression}). * @since 3.0 */ public static final ChildListPropertyDescriptor UPDATERS_PROPERTY = new ChildListPropertyDescriptor( ForStatement.class, "updaters", Expression.class, CYCLE_RISK); //$NON-NLS-1$ /** * The "body" structural property of this node type (child type: {@link Statement}). * @since 3.0 */ public static final ChildPropertyDescriptor BODY_PROPERTY = new ChildPropertyDescriptor(ForStatement.class, "body", Statement.class, MANDATORY, 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 properyList = new ArrayList(5); createPropertyList(ForStatement.class, properyList); addProperty(INITIALIZERS_PROPERTY, properyList); addProperty(EXPRESSION_PROPERTY, properyList); addProperty(UPDATERS_PROPERTY, properyList); addProperty(BODY_PROPERTY, properyList); PROPERTY_DESCRIPTORS = reapPropertyList(properyList); } /** * 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 list of initializer expressions (element type: * {@link Expression}). Defaults to an empty list. */ private ASTNode.NodeList initializers = new ASTNode.NodeList(INITIALIZERS_PROPERTY); /** * The condition expression; <code>null</code> for none; defaults to none. */ private Expression optionalConditionExpression = null; /** * The list of update expressions (element type: * {@link Expression}). Defaults to an empty list. */ private ASTNode.NodeList updaters = new ASTNode.NodeList(UPDATERS_PROPERTY); /** * The body statement; lazily initialized; defaults to an empty block * statement. */ private Statement body = null; /** * Creates a new AST node for a for statement owned by the given AST. * By default, there are no initializers, no condition expression, * no updaters, and the body is an empty block. * * @param ast the AST that is to own this node */ ForStatement(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; } } if (property == BODY_PROPERTY) { if (get) { return getBody(); } else { setBody((Statement) child); return null; } } // allow default implementation to flag the error return super.internalGetSetChildProperty(property, get, child); } @Override final List internalGetChildListProperty(ChildListPropertyDescriptor property) { if (property == INITIALIZERS_PROPERTY) { return initializers(); } if (property == UPDATERS_PROPERTY) { return updaters(); } // allow default implementation to flag the error return super.internalGetChildListProperty(property); } @Override final int getNodeType0() { return FOR_STATEMENT; } @Override ASTNode clone0(AST target) { ForStatement result = new ForStatement(target); result.setSourceRange(getStartPosition(), getLength()); result.copyLeadingComment(this); result.initializers().addAll(ASTNode.copySubtrees(target, initializers())); result.setExpression((Expression) ASTNode.copySubtree(target, getExpression())); result.updaters().addAll(ASTNode.copySubtrees(target, updaters())); result.setBody((Statement) ASTNode.copySubtree(target, getBody())); 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 acceptChildren(visitor, this.initializers); acceptChild(visitor, getExpression()); acceptChildren(visitor, this.updaters); acceptChild(visitor, getBody()); } visitor.endVisit(this); } /** * Returns the live ordered list of initializer expressions in this for * statement. * <p> * The list should consist of either a list of so called statement * expressions (JLS2, 14.8), or a single <code>VariableDeclarationExpression</code>. * Otherwise, the for statement would have no Java source equivalent. * </p> * * @return the live list of initializer expressions * (element type: {@link Expression}) */ public List initializers() { return this.initializers; } /** * Returns the condition expression of this for statement, or * <code>null</code> if there is none. * * @return the condition expression node, or <code>null</code> if * there is none */ public Expression getExpression() { return this.optionalConditionExpression; } /** * Sets or clears the condition expression of this return statement. * * @param expression the condition expression node, or <code>null</code> * if there is none * @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) { ASTNode oldChild = this.optionalConditionExpression; preReplaceChild(oldChild, expression, EXPRESSION_PROPERTY); this.optionalConditionExpression = expression; postReplaceChild(oldChild, expression, EXPRESSION_PROPERTY); } /** * Returns the live ordered list of update expressions in this for * statement. * <p> * The list should consist of so called statement expressions. Otherwise, * the for statement would have no Java source equivalent. * </p> * * @return the live list of update expressions * (element type: {@link Expression}) */ public List updaters() { return this.updaters; } /** * Returns the body of this for statement. * * @return the body statement node */ public Statement getBody() { if (this.body == null) { // lazy init must be thread-safe for readers synchronized (this) { if (this.body == null) { preLazyInit(); this.body = new Block(this.ast); postLazyInit(this.body, BODY_PROPERTY); } } } return this.body; } /** * Sets the body of this for statement. * <p> * Special note: The Java language does not allow a local variable declaration * to appear as the body of a for statement (they may only appear within a * block). However, the AST will allow a <code>VariableDeclarationStatement</code> * as the body of a <code>ForStatement</code>. To get something that will * compile, be sure to embed the <code>VariableDeclarationStatement</code> * inside a <code>Block</code>. * </p> * * @param statement the body statement 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 setBody(Statement statement) { if (statement == null) { throw new IllegalArgumentException(); } ASTNode oldChild = this.body; preReplaceChild(oldChild, statement, BODY_PROPERTY); this.body = statement; postReplaceChild(oldChild, statement, BODY_PROPERTY); } @Override int memSize() { return super.memSize() + 4 * 4; } @Override int treeSize() { return memSize() + this.initializers.listSize() + this.updaters.listSize() + (this.optionalConditionExpression == null ? 0 : getExpression().treeSize()) + (this.body == null ? 0 : getBody().treeSize()); } }