Java tutorial
/* * Copyright 2002-2019 the original author or authors. * * Licensed 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 * * https://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.springframework.transaction.annotation; import java.io.Serializable; import java.lang.reflect.AnnotatedElement; import java.lang.reflect.Method; import java.util.Arrays; import java.util.Collections; import java.util.LinkedHashSet; import java.util.Set; import org.springframework.lang.Nullable; import org.springframework.transaction.interceptor.AbstractFallbackTransactionAttributeSource; import org.springframework.transaction.interceptor.TransactionAttribute; import org.springframework.util.Assert; import org.springframework.util.ClassUtils; /** * Implementation of the * {@link org.springframework.transaction.interceptor.TransactionAttributeSource} * interface for working with transaction metadata in JDK 1.5+ annotation format. * * <p>This class reads Spring's JDK 1.5+ {@link Transactional} annotation and * exposes corresponding transaction attributes to Spring's transaction infrastructure. * Also supports JTA 1.2's {@link javax.transaction.Transactional} and EJB3's * {@link javax.ejb.TransactionAttribute} annotation (if present). * This class may also serve as base class for a custom TransactionAttributeSource, * or get customized through {@link TransactionAnnotationParser} strategies. * * @author Colin Sampaleanu * @author Juergen Hoeller * @since 1.2 * @see Transactional * @see TransactionAnnotationParser * @see SpringTransactionAnnotationParser * @see Ejb3TransactionAnnotationParser * @see org.springframework.transaction.interceptor.TransactionInterceptor#setTransactionAttributeSource * @see org.springframework.transaction.interceptor.TransactionProxyFactoryBean#setTransactionAttributeSource */ @SuppressWarnings("serial") public class AnnotationTransactionAttributeSource extends AbstractFallbackTransactionAttributeSource implements Serializable { private static final boolean jta12Present; private static final boolean ejb3Present; static { ClassLoader classLoader = AnnotationTransactionAttributeSource.class.getClassLoader(); jta12Present = ClassUtils.isPresent("javax.transaction.Transactional", classLoader); ejb3Present = ClassUtils.isPresent("javax.ejb.TransactionAttribute", classLoader); } private final boolean publicMethodsOnly; private final Set<TransactionAnnotationParser> annotationParsers; /** * Create a default AnnotationTransactionAttributeSource, supporting * public methods that carry the {@code Transactional} annotation * or the EJB3 {@link javax.ejb.TransactionAttribute} annotation. */ public AnnotationTransactionAttributeSource() { this(true); } /** * Create a custom AnnotationTransactionAttributeSource, supporting * public methods that carry the {@code Transactional} annotation * or the EJB3 {@link javax.ejb.TransactionAttribute} annotation. * @param publicMethodsOnly whether to support public methods that carry * the {@code Transactional} annotation only (typically for use * with proxy-based AOP), or protected/private methods as well * (typically used with AspectJ class weaving) */ public AnnotationTransactionAttributeSource(boolean publicMethodsOnly) { this.publicMethodsOnly = publicMethodsOnly; if (jta12Present || ejb3Present) { this.annotationParsers = new LinkedHashSet<>(4); this.annotationParsers.add(new SpringTransactionAnnotationParser()); if (jta12Present) { this.annotationParsers.add(new JtaTransactionAnnotationParser()); } if (ejb3Present) { this.annotationParsers.add(new Ejb3TransactionAnnotationParser()); } } else { this.annotationParsers = Collections.singleton(new SpringTransactionAnnotationParser()); } } /** * Create a custom AnnotationTransactionAttributeSource. * @param annotationParser the TransactionAnnotationParser to use */ public AnnotationTransactionAttributeSource(TransactionAnnotationParser annotationParser) { this.publicMethodsOnly = true; Assert.notNull(annotationParser, "TransactionAnnotationParser must not be null"); this.annotationParsers = Collections.singleton(annotationParser); } /** * Create a custom AnnotationTransactionAttributeSource. * @param annotationParsers the TransactionAnnotationParsers to use */ public AnnotationTransactionAttributeSource(TransactionAnnotationParser... annotationParsers) { this.publicMethodsOnly = true; Assert.notEmpty(annotationParsers, "At least one TransactionAnnotationParser needs to be specified"); this.annotationParsers = new LinkedHashSet<>(Arrays.asList(annotationParsers)); } /** * Create a custom AnnotationTransactionAttributeSource. * @param annotationParsers the TransactionAnnotationParsers to use */ public AnnotationTransactionAttributeSource(Set<TransactionAnnotationParser> annotationParsers) { this.publicMethodsOnly = true; Assert.notEmpty(annotationParsers, "At least one TransactionAnnotationParser needs to be specified"); this.annotationParsers = annotationParsers; } @Override public boolean isCandidateClass(Class<?> targetClass) { for (TransactionAnnotationParser parser : this.annotationParsers) { if (parser.isCandidateClass(targetClass)) { return true; } } return false; } @Override @Nullable protected TransactionAttribute findTransactionAttribute(Class<?> clazz) { return determineTransactionAttribute(clazz); } @Override @Nullable protected TransactionAttribute findTransactionAttribute(Method method) { return determineTransactionAttribute(method); } /** * Determine the transaction attribute for the given method or class. * <p>This implementation delegates to configured * {@link TransactionAnnotationParser TransactionAnnotationParsers} * for parsing known annotations into Spring's metadata attribute class. * Returns {@code null} if it's not transactional. * <p>Can be overridden to support custom annotations that carry transaction metadata. * @param element the annotated method or class * @return the configured transaction attribute, or {@code null} if none was found */ @Nullable protected TransactionAttribute determineTransactionAttribute(AnnotatedElement element) { for (TransactionAnnotationParser parser : this.annotationParsers) { TransactionAttribute attr = parser.parseTransactionAnnotation(element); if (attr != null) { return attr; } } return null; } /** * By default, only public methods can be made transactional. */ @Override protected boolean allowPublicMethodsOnly() { return this.publicMethodsOnly; } @Override public boolean equals(@Nullable Object other) { if (this == other) { return true; } if (!(other instanceof AnnotationTransactionAttributeSource)) { return false; } AnnotationTransactionAttributeSource otherTas = (AnnotationTransactionAttributeSource) other; return (this.annotationParsers.equals(otherTas.annotationParsers) && this.publicMethodsOnly == otherTas.publicMethodsOnly); } @Override public int hashCode() { return this.annotationParsers.hashCode(); } }