/*
* Copyright 2006-2013 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
*
* 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.springframework.batch.core.step.skip;
import java.io.FileNotFoundException;
import java.util.Collections;
import java.util.Map;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepExecution;
import org.springframework.batch.item.file.FlatFileParseException;
import org.springframework.classify.BinaryExceptionClassifier;
import org.springframework.classify.Classifier;
/**
* <p>
* {@link SkipPolicy} that determines whether or not reading should continue
* based upon how many items have been skipped. This is extremely useful
* behavior, as it allows you to skip records, but will throw a
* {@link SkipLimitExceededException} if a set limit has been exceeded. For
* example, it is generally advisable to skip {@link FlatFileParseException}s,
* however, if the vast majority of records are causing exceptions, the file is
* likely bad.
* </p>
*
* <p>
* Furthermore, it is also likely that you only want to skip certain exceptions.
* {@link FlatFileParseException} is a good example of an exception you will
* likely want to skip, but a {@link FileNotFoundException} should cause
* immediate termination of the {@link Step}. A {@link Classifier} is used to
* determine whether a particular exception is skippable or not.
* </p>
*
* @author Ben Hale
* @author Lucas Ward
* @author Robert Kasanicky
* @author Dave Syer
* @author Dan Garrette
*/
public class LimitCheckingItemSkipPolicy implements SkipPolicy {
private int skipLimit;
private Classifier<Throwable, Boolean> skippableExceptionClassifier;
/**
* Convenience constructor that assumes all exception types are fatal.
*/
public LimitCheckingItemSkipPolicy() {
this(0, Collections.<Class<? extends Throwable>, Boolean> emptyMap());
}
/**
* @param skipLimit the number of skippable exceptions that are allowed to
* be skipped
* @param skippableExceptions exception classes that can be skipped
* (non-critical)
*/
public LimitCheckingItemSkipPolicy(int skipLimit, Map<Class<? extends Throwable>, Boolean> skippableExceptions) {
this(skipLimit, new BinaryExceptionClassifier(skippableExceptions));
}
/**
* @param skipLimit the number of skippable exceptions that are allowed to
* be skipped
* @param skippableExceptionClassifier exception classifier for those that
* can be skipped (non-critical)
*/
public LimitCheckingItemSkipPolicy(int skipLimit, Classifier<Throwable, Boolean> skippableExceptionClassifier) {
this.skipLimit = skipLimit;
this.skippableExceptionClassifier = skippableExceptionClassifier;
}
/**
* The absolute number of skips (of skippable exceptions) that can be
* tolerated before a failure.
*
* @param skipLimit the skip limit to set
*/
public void setSkipLimit(int skipLimit) {
this.skipLimit = skipLimit;
}
/**
* The classifier that will be used to decide on skippability. If an
* exception classifies as "true" then it is skippable, and otherwise not.
*
* @param skippableExceptionClassifier the skippableExceptionClassifier to
* set
*/
public void setSkippableExceptionClassifier(Classifier<Throwable, Boolean> skippableExceptionClassifier) {
this.skippableExceptionClassifier = skippableExceptionClassifier;
}
/**
* Set up the classifier through a convenient map from throwable class to
* boolean (true if skippable).
*
* @param skippableExceptions the skippable exceptions to set
*/
public void setSkippableExceptionMap(Map<Class<? extends Throwable>, Boolean> skippableExceptions) {
this.skippableExceptionClassifier = new BinaryExceptionClassifier(skippableExceptions);
}
/**
* Given the provided exception and skip count, determine whether or not
* processing should continue for the given exception. If the exception is
* not classified as skippable in the classifier, false will be returned. If
* the exception is classified as skippable and {@link StepExecution}
* skipCount is greater than the skipLimit, then a
* {@link SkipLimitExceededException} will be thrown.
*/
@Override
public boolean shouldSkip(Throwable t, int skipCount) {
if (skippableExceptionClassifier.classify(t)) {
if (skipCount < skipLimit) {
return true;
}
else {
throw new SkipLimitExceededException(skipLimit, t);
}
}
else {
return false;
}
}
}