| 1 | /* |
| 2 | * Copyright 2006-2007 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package org.springframework.batch.repeat.support; |
| 18 | |
| 19 | import org.springframework.batch.repeat.RepeatCallback; |
| 20 | import org.springframework.batch.repeat.RepeatContext; |
| 21 | import org.springframework.batch.repeat.RepeatOperations; |
| 22 | |
| 23 | /** |
| 24 | * Global variable support for repeat clients. Normally it is not necessary for |
| 25 | * clients to be aware of the surrounding environment because a |
| 26 | * {@link RepeatCallback} can always use the context it is passed by the |
| 27 | * enclosing {@link RepeatOperations}. But occasionally it might be helpful to |
| 28 | * have lower level access to the ongoing {@link RepeatContext} so we provide a |
| 29 | * global accessor here. The mutator methods ({@link #clear()} and |
| 30 | * {@link #register(RepeatContext)} should not be used except internally by |
| 31 | * {@link RepeatOperations} implementations. |
| 32 | * |
| 33 | * @author Dave Syer |
| 34 | * |
| 35 | */ |
| 36 | public class RepeatSynchronizationManager { |
| 37 | |
| 38 | private static final ThreadLocal contextHolder = new ThreadLocal(); |
| 39 | |
| 40 | private RepeatSynchronizationManager() { |
| 41 | } |
| 42 | |
| 43 | /** |
| 44 | * Getter for the current context. A context is shared by all items in the |
| 45 | * batch, so this method is intended to return the same context object |
| 46 | * independent of whether the callback is running synchronously or |
| 47 | * asynchronously with the surrounding {@link RepeatOperations}. |
| 48 | * |
| 49 | * @return the current {@link RepeatContext} or null if there is none (if we |
| 50 | * are not in a batch). |
| 51 | */ |
| 52 | public static RepeatContext getContext() { |
| 53 | return (RepeatContext) contextHolder.get(); |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * Convenience method to set the current repeat operation to complete if it |
| 58 | * exists. |
| 59 | */ |
| 60 | public static void setCompleteOnly() { |
| 61 | RepeatContext context = getContext(); |
| 62 | if (context != null) { |
| 63 | context.setCompleteOnly(); |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | /** |
| 68 | * Method for registering a context - should only be used by |
| 69 | * {@link RepeatOperations} implementations to ensure that |
| 70 | * {@link #getContext()} always returns the correct value. |
| 71 | * |
| 72 | * @param context a new context at the start of a batch. |
| 73 | * @return the old value if there was one. |
| 74 | */ |
| 75 | public static RepeatContext register(RepeatContext context) { |
| 76 | RepeatContext oldSession = getContext(); |
| 77 | RepeatSynchronizationManager.contextHolder.set(context); |
| 78 | return oldSession; |
| 79 | } |
| 80 | |
| 81 | /** |
| 82 | * Clear the current context at the end of a batch - should only be used by |
| 83 | * {@link RepeatOperations} implementations. |
| 84 | * |
| 85 | * @return the old value if there was one. |
| 86 | */ |
| 87 | public static RepeatContext clear() { |
| 88 | RepeatContext context = getContext(); |
| 89 | RepeatSynchronizationManager.contextHolder.set(null); |
| 90 | return context; |
| 91 | } |
| 92 | |
| 93 | /** |
| 94 | * Set current session and all ancestors (via parent) to complete., |
| 95 | */ |
| 96 | public static void setAncestorsCompleteOnly() { |
| 97 | RepeatContext context = getContext(); |
| 98 | while (context != null) { |
| 99 | context.setCompleteOnly(); |
| 100 | context = context.getParent(); |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | } |