Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2017 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; /** * Try statement AST node type. * <pre> * TryStatement: * <b>try</b> [ <b>(</b> Resources <b>)</b> ] * Block * [ { CatchClause } ] * [ <b>finally</b> Block ] * </pre> * * <p> * Not all node arrangements will represent legal Java constructs. In particular, * at least one resource, catch clause, or finally block must be present.</p> * * <p>A resource is either a {@link VariableDeclarationExpression} or (since JLS9) a {@link Name}.</p> * * @since 2.0 * @noinstantiate This class is not intended to be instantiated by clients. * @noextend This class is not intended to be subclassed by clients. */ @SuppressWarnings({ "rawtypes", "unchecked" }) public class TryStatement extends Statement { /** * The "resources" structural property of this node type (element type: {@link VariableDeclarationExpression}) (added in JLS4 API). * @deprecated In the JLS9 API, this property is replaced by {@link #RESOURCES2_PROPERTY}. * @since 3.7.1 */ public static final ChildListPropertyDescriptor RESOURCES_PROPERTY = new ChildListPropertyDescriptor( TryStatement.class, "resources", VariableDeclarationExpression.class, CYCLE_RISK); //$NON-NLS-1$ /** * The "resources" structural property of this node type (element type: {@link Expression}) (added in JLS9 API). * @since 3.14 */ public static final ChildListPropertyDescriptor RESOURCES2_PROPERTY = new ChildListPropertyDescriptor( TryStatement.class, "resources", Expression.class, 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(TryStatement.class, "body", Block.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$ /** * The "catchClauses" structural property of this node type (element type: {@link CatchClause}). * @since 3.0 */ public static final ChildListPropertyDescriptor CATCH_CLAUSES_PROPERTY = new ChildListPropertyDescriptor( TryStatement.class, "catchClauses", CatchClause.class, CYCLE_RISK); //$NON-NLS-1$ /** * The "finally" structural property of this node type (child type: {@link Block}). * @since 3.0 */ public static final ChildPropertyDescriptor FINALLY_PROPERTY = new ChildPropertyDescriptor(TryStatement.class, "finally", Block.class, OPTIONAL, CYCLE_RISK); //$NON-NLS-1$ /** * A list of property descriptors (element type: * {@link StructuralPropertyDescriptor}), * or null if uninitialized. */ private static final List PROPERTY_DESCRIPTORS; /** * A list of property descriptors (element type: * {@link StructuralPropertyDescriptor}), * or null if uninitialized. * @since 3.7 */ private static final List PROPERTY_DESCRIPTORS_4_0; /** * A list of property descriptors (element type: * {@link StructuralPropertyDescriptor}), * or null if uninitialized. * @since 3.14 */ private static final List PROPERTY_DESCRIPTORS_9_0; static { List propertyList = new ArrayList(4); createPropertyList(TryStatement.class, propertyList); addProperty(BODY_PROPERTY, propertyList); addProperty(CATCH_CLAUSES_PROPERTY, propertyList); addProperty(FINALLY_PROPERTY, propertyList); PROPERTY_DESCRIPTORS = reapPropertyList(propertyList); propertyList = new ArrayList(5); createPropertyList(TryStatement.class, propertyList); addProperty(RESOURCES_PROPERTY, propertyList); addProperty(BODY_PROPERTY, propertyList); addProperty(CATCH_CLAUSES_PROPERTY, propertyList); addProperty(FINALLY_PROPERTY, propertyList); PROPERTY_DESCRIPTORS_4_0 = reapPropertyList(propertyList); propertyList = new ArrayList(5); createPropertyList(TryStatement.class, propertyList); addProperty(RESOURCES2_PROPERTY, propertyList); addProperty(BODY_PROPERTY, propertyList); addProperty(CATCH_CLAUSES_PROPERTY, propertyList); addProperty(FINALLY_PROPERTY, propertyList); PROPERTY_DESCRIPTORS_9_0 = 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) { switch (apiLevel) { case AST.JLS2_INTERNAL: case AST.JLS3_INTERNAL: return PROPERTY_DESCRIPTORS; case AST.JLS4_INTERNAL: case AST.JLS8_INTERNAL: return PROPERTY_DESCRIPTORS_4_0; default: return PROPERTY_DESCRIPTORS_9_0; } } /** * The resource expressions (element type: {@link Expression}). * Null in JLS2 and JLS3. Added in JLS4. * In the deprecated JLS4 and JLS8 APIs, this used to be * (element type: {@link VariableDeclarationExpression}). * Defaults to an empty list (see constructor). * @since 3.7 */ private ASTNode.NodeList resources = null; /** * The body; lazily initialized; defaults to an empty block. */ private Block body = null; /** * The catch clauses (element type: {@link CatchClause}). * Defaults to an empty list. */ private ASTNode.NodeList catchClauses = new ASTNode.NodeList(CATCH_CLAUSES_PROPERTY); /** * The finally block, or <code>null</code> if none. * Defaults to none. */ private Block optionalFinallyBody = null; /** * Creates a new AST node for a try statement owned by the given * AST. By default, the try statement has no resources, an empty block, no catch * clauses, and no finally block. * <p> * N.B. This constructor is package-private. * </p> * * @param ast the AST that is to own this node */ TryStatement(AST ast) { super(ast); if (ast.apiLevel >= AST.JLS9_INTERNAL) { this.resources = new ASTNode.NodeList(RESOURCES2_PROPERTY); } else if (ast.apiLevel >= AST.JLS4_INTERNAL) { this.resources = new ASTNode.NodeList(RESOURCES_PROPERTY); } } @Override final List internalStructuralPropertiesForType(int apiLevel) { return propertyDescriptors(apiLevel); } @Override final ASTNode internalGetSetChildProperty(ChildPropertyDescriptor property, boolean get, ASTNode child) { if (property == BODY_PROPERTY) { if (get) { return getBody(); } else { setBody((Block) child); return null; } } if (property == FINALLY_PROPERTY) { if (get) { return getFinally(); } else { setFinally((Block) child); return null; } } // allow default implementation to flag the error return super.internalGetSetChildProperty(property, get, child); } @Override final List internalGetChildListProperty(ChildListPropertyDescriptor property) { if (property == RESOURCES_PROPERTY || property == RESOURCES2_PROPERTY) { return resources(); } if (property == CATCH_CLAUSES_PROPERTY) { return catchClauses(); } // allow default implementation to flag the error return super.internalGetChildListProperty(property); } @Override final int getNodeType0() { return TRY_STATEMENT; } @Override ASTNode clone0(AST target) { TryStatement result = new TryStatement(target); result.setSourceRange(getStartPosition(), getLength()); result.copyLeadingComment(this); if (this.ast.apiLevel >= AST.JLS4_INTERNAL) { result.resources().addAll(ASTNode.copySubtrees(target, resources())); } result.setBody((Block) getBody().clone(target)); result.catchClauses().addAll(ASTNode.copySubtrees(target, catchClauses())); result.setFinally((Block) ASTNode.copySubtree(target, getFinally())); 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 if (this.ast.apiLevel >= AST.JLS4_INTERNAL) { acceptChildren(visitor, this.resources); } acceptChild(visitor, getBody()); acceptChildren(visitor, this.catchClauses); acceptChild(visitor, getFinally()); } visitor.endVisit(this); } /** * Returns the body of this try statement. * * @return the try 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 try statement. * * @param body the 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); } /** * Returns the live ordered list of catch clauses for this try statement. * * @return the live list of catch clauses * (element type: {@link CatchClause}) */ public List catchClauses() { return this.catchClauses; } /** * Returns the finally block of this try statement, or <code>null</code> if * this try statement has <b>no</b> finally block. * * @return the finally block, or <code>null</code> if this try statement * has none */ public Block getFinally() { return this.optionalFinallyBody; } /** * Sets or clears the finally block of this try statement. * * @param block the finally block 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 setFinally(Block block) { ASTNode oldChild = this.optionalFinallyBody; preReplaceChild(oldChild, block, FINALLY_PROPERTY); this.optionalFinallyBody = block; postReplaceChild(oldChild, block, FINALLY_PROPERTY); } /** * Returns the live ordered list of resources for this try statement (added in JLS4 API). * * <p>A resource is either a {@link VariableDeclarationExpression} or (since JLS9) a {@link Name}.</p> * * @return the live list of resources (element type: {@link Expression}). * In the deprecated JLS4 and JLS8 APIs, this used to be * (element type: {@link VariableDeclarationExpression}). * @exception UnsupportedOperationException if this operation is used * in a JLS2 or JLS3 AST * @since 3.7.1 */ public List resources() { // more efficient than just calling unsupportedIn2_3() to check if (this.resources == null) { unsupportedIn2_3(); } return this.resources; } @Override int memSize() { return super.memSize() + 4 * 4; } @Override int treeSize() { return memSize() + (this.resources == null ? 0 : this.resources.listSize()) + (this.body == null ? 0 : getBody().treeSize()) + this.catchClauses.listSize() + (this.optionalFinallyBody == null ? 0 : getFinally().treeSize()); } }