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; /** * Catch clause AST node type. * * <pre> * CatchClause: * <b>catch</b> <b>(</b> FormalParameter <b>)</b> Block * </pre> * * <p>The FormalParameter is represented by a {@link SingleVariableDeclaration}.</p> * @since 2.0 * @noinstantiate This class is not intended to be instantiated by clients. */ @SuppressWarnings("rawtypes") public class CatchClause extends ASTNode { /** * The "exception" structural property of this node type (child type: {@link SingleVariableDeclaration}). * @since 3.0 */ public static final ChildPropertyDescriptor EXCEPTION_PROPERTY = new ChildPropertyDescriptor(CatchClause.class, "exception", SingleVariableDeclaration.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$ /** * The "body" structural property of this node type (child type: {@link Block}). * @since 3.0 */ public static final ChildPropertyDescriptor BODY_PROPERTY = new ChildPropertyDescriptor(CatchClause.class, "body", Block.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(3); createPropertyList(CatchClause.class, properyList); addProperty(EXCEPTION_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 body; lazily initialized; defaults to an empty block. */ private Block body = null; /** * The exception variable declaration; lazily initialized; defaults to a * unspecified, but legal, variable declaration. */ private SingleVariableDeclaration exceptionDecl = null; /** * Creates a new AST node for a catch clause owned by the given * AST. By default, the catch clause declares an unspecified, but legal, * exception declaration and has an empty block. * <p> * N.B. This constructor is package-private. * </p> * * @param ast the AST that is to own this node */ CatchClause(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 == EXCEPTION_PROPERTY) { if (get) { return getException(); } else { setException((SingleVariableDeclaration) child); return null; } } if (property == BODY_PROPERTY) { if (get) { return getBody(); } else { setBody((Block) child); return null; } } // allow default implementation to flag the error return super.internalGetSetChildProperty(property, get, child); } @Override final int getNodeType0() { return CATCH_CLAUSE; } @Override ASTNode clone0(AST target) { CatchClause result = new CatchClause(target); result.setSourceRange(getStartPosition(), getLength()); result.setBody((Block) getBody().clone(target)); result.setException((SingleVariableDeclaration) ASTNode.copySubtree(target, getException())); 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, getException()); acceptChild(visitor, getBody()); } visitor.endVisit(this); } /** * Returns the exception variable declaration of this catch clause. * * @return the exception variable declaration node */ public SingleVariableDeclaration getException() { if (this.exceptionDecl == null) { // lazy init must be thread-safe for readers synchronized (this) { if (this.exceptionDecl == null) { preLazyInit(); this.exceptionDecl = new SingleVariableDeclaration(this.ast); postLazyInit(this.exceptionDecl, EXCEPTION_PROPERTY); } } } return this.exceptionDecl; } /** * Sets the variable declaration of this catch clause. * * @param exception the exception variable declaration 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 setException(SingleVariableDeclaration exception) { if (exception == null) { throw new IllegalArgumentException(); } ASTNode oldChild = this.exceptionDecl; preReplaceChild(oldChild, exception, EXCEPTION_PROPERTY); this.exceptionDecl = exception; postReplaceChild(oldChild, exception, EXCEPTION_PROPERTY); } /** * Returns the body of this catch clause. * * @return the catch clause body */ public Block 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 catch clause. * * @param body the catch clause block 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(Block body) { if (body == null) { throw new IllegalArgumentException(); } ASTNode oldChild = this.body; preReplaceChild(oldChild, body, BODY_PROPERTY); this.body = body; postReplaceChild(oldChild, body, BODY_PROPERTY); } @Override int memSize() { // treat Code as free return BASE_NODE_SIZE + 2 * 4; } @Override int treeSize() { return memSize() + (this.exceptionDecl == null ? 0 : getException().treeSize()) + (this.body == null ? 0 : getBody().treeSize()); } }