| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.codehaus.groovy.ast.expr; |
| |
| import org.codehaus.groovy.ast.ASTNode; |
| import org.codehaus.groovy.ast.AnnotationNode; |
| import org.codehaus.groovy.ast.ClassNode; |
| import org.codehaus.groovy.ast.GroovyCodeVisitor; |
| |
| import java.util.Map; |
| |
| /** |
| * Placeholder for an empty expression. Empty expressions are used in closures |
| * lists like (;). During class generation empty expressions should be ignored |
| * or replaced with a null value. |
| * |
| * @see org.codehaus.groovy.ast.stmt.EmptyStatement |
| */ |
| public class EmptyExpression extends Expression { |
| |
| /** |
| * @see EmptyExpression#INSTANCE |
| */ |
| public EmptyExpression() { |
| super(); |
| } |
| |
| @Override |
| public Expression transformExpression(ExpressionTransformer transformer) { |
| return this; |
| } |
| |
| @Override |
| public void visit(GroovyCodeVisitor visitor) { |
| visitor.visitEmptyExpression(this); |
| } |
| |
| //-------------------------------------------------------------------------- |
| |
| /** |
| * Immutable singleton that is recommended for use when source range or any |
| * other occurrence-specific metadata is not needed. |
| */ |
| public static final EmptyExpression INSTANCE = new EmptyExpression() { |
| |
| private void throwUnsupportedOperationException() { |
| throw new UnsupportedOperationException("EmptyExpression.INSTANCE is immutable"); |
| } |
| |
| // ASTNode overrides: |
| |
| @Override |
| public void setColumnNumber(int n) { |
| throwUnsupportedOperationException(); |
| } |
| |
| @Override |
| public void setLastColumnNumber(int n) { |
| throwUnsupportedOperationException(); |
| } |
| |
| @Override |
| public void setLastLineNumber(int n) { |
| throwUnsupportedOperationException(); |
| } |
| |
| @Override |
| public void setLineNumber(int n) { |
| throwUnsupportedOperationException(); |
| } |
| |
| @Override |
| public void setMetaDataMap(Map<?, ?> meta) { |
| throwUnsupportedOperationException(); |
| } |
| |
| @Override |
| public void setSourcePosition(ASTNode node) { |
| throwUnsupportedOperationException(); |
| } |
| |
| // AnnotatedNode overrides: |
| |
| @Override |
| public void addAnnotation(AnnotationNode node) { |
| throwUnsupportedOperationException(); |
| } |
| |
| @Override |
| public void setDeclaringClass(ClassNode node) { |
| throwUnsupportedOperationException(); |
| } |
| |
| @Override |
| public void setHasNoRealSourcePosition(boolean b) { |
| throwUnsupportedOperationException(); |
| } |
| |
| @Override |
| public void setSynthetic(boolean b) { |
| throwUnsupportedOperationException(); |
| } |
| |
| // Expression overrides: |
| |
| @Override |
| public void setType(ClassNode node) { |
| throwUnsupportedOperationException(); |
| } |
| }; |
| } |