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 | package org.springframework.batch.core.step.skip; |
17 | |
18 | import java.io.FileNotFoundException; |
19 | import java.util.Collections; |
20 | import java.util.HashMap; |
21 | import java.util.Iterator; |
22 | import java.util.List; |
23 | import java.util.Map; |
24 | |
25 | import org.springframework.batch.core.Step; |
26 | import org.springframework.batch.core.StepExecution; |
27 | import org.springframework.batch.item.file.FlatFileParseException; |
28 | import org.springframework.batch.support.ExceptionClassifier; |
29 | import org.springframework.batch.support.SubclassExceptionClassifier; |
30 | |
31 | /** |
32 | * <p> |
33 | * {@link ItemSkipPolicy} that determines whether or not reading should continue |
34 | * based upon how many items have been skipped. This is extremely useful |
35 | * behavior, as it allows you to skip records, but will throw a |
36 | * {@link SkipLimitExceededException} if a set limit has been exceeded. For |
37 | * example, it is generally advisable to skip {@link FlatFileParseException}s, |
38 | * however, if the vast majority of records are causing exceptions, the file is |
39 | * likely bad. |
40 | * </p> |
41 | * |
42 | * <p> |
43 | * Furthermore, it is also likely that you only want to skip certain exceptions. |
44 | * {@link FlatFileParseException} is a good example of an exception you will |
45 | * likely want to skip, but a {@link FileNotFoundException} should cause |
46 | * immediate termination of the {@link Step}. Because it would be impossible |
47 | * for a general purpose policy to determine all the types of exceptions that |
48 | * should be skipped from those that shouldn't, two lists must be passed in, |
49 | * with all of the exceptions that are 'fatal' and 'skippable'. The two lists |
50 | * are not enforced to be exclusive, they are prioritized instead - exceptions |
51 | * that are fatal will never be skipped, regardless whether the exception can |
52 | * also be classified as skippable. |
53 | * </p> |
54 | * |
55 | * @author Ben Hale |
56 | * @author Lucas Ward |
57 | * @author Robert Kasanicky |
58 | */ |
59 | public class LimitCheckingItemSkipPolicy implements ItemSkipPolicy { |
60 | |
61 | /** |
62 | * Label for classifying skippable exceptions. |
63 | */ |
64 | private static final String SKIP = "skip"; |
65 | |
66 | /** |
67 | * Label for classifying fatal exceptions - these are never skipped. |
68 | */ |
69 | private static final String NEVER_SKIP = "neverSkip"; |
70 | |
71 | private final int skipLimit; |
72 | |
73 | private ExceptionClassifier exceptionClassifier; |
74 | |
75 | /** |
76 | * Convenience constructor that assumes all exception types are skippable |
77 | * and none are fatal. |
78 | * @param skipLimit the number of exceptions allowed to skip |
79 | */ |
80 | public LimitCheckingItemSkipPolicy(int skipLimit) { |
81 | this(skipLimit, Collections.singletonList(Exception.class), Collections.EMPTY_LIST); |
82 | } |
83 | |
84 | /** |
85 | * |
86 | * @param skipLimit the number of skippable exceptions that are allowed to |
87 | * be skipped |
88 | * @param skippableExceptions exception classes that can be skipped |
89 | * (non-critical) |
90 | * @param fatalExceptions exception classes that should never be skipped |
91 | */ |
92 | public LimitCheckingItemSkipPolicy(int skipLimit, List skippableExceptions, List fatalExceptions) { |
93 | this.skipLimit = skipLimit; |
94 | SubclassExceptionClassifier exceptionClassifier = new SubclassExceptionClassifier(); |
95 | Map typeMap = new HashMap(); |
96 | for (Iterator iterator = skippableExceptions.iterator(); iterator.hasNext();) { |
97 | Class throwable = (Class) iterator.next(); |
98 | typeMap.put(throwable, SKIP); |
99 | } |
100 | for (Iterator iterator = fatalExceptions.iterator(); iterator.hasNext();) { |
101 | Class throwable = (Class) iterator.next(); |
102 | typeMap.put(throwable, NEVER_SKIP); |
103 | } |
104 | exceptionClassifier.setTypeMap(typeMap); |
105 | this.exceptionClassifier = exceptionClassifier; |
106 | } |
107 | |
108 | /** |
109 | * Given the provided exception and skip count, determine whether or not |
110 | * processing should continue for the given exception. If the exception is |
111 | * not within the list of 'skippable exceptions' or belongs to the list of |
112 | * 'fatal exceptions', false will be returned. If the exception is within |
113 | * the skippable list (and not in the fatal list), and {@link StepExecution} |
114 | * skipCount is greater than the skipLimit, then a |
115 | * {@link SkipLimitExceededException} will be thrown. |
116 | */ |
117 | public boolean shouldSkip(Throwable t, int skipCount) { |
118 | if (exceptionClassifier.classify(t).equals(NEVER_SKIP)) { |
119 | return false; |
120 | } |
121 | if (exceptionClassifier.classify(t).equals(SKIP)) { |
122 | if (skipCount < skipLimit) { |
123 | return true; |
124 | } |
125 | else { |
126 | throw new SkipLimitExceededException(skipLimit, t); |
127 | } |
128 | } |
129 | else { |
130 | return false; |
131 | } |
132 | } |
133 | |
134 | } |