org.supercsv.cellprocessor.constraint.RequireHashCode Maven / Gradle / Ivy
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/*
* Copyright 2007 Kasper B. Graversen
*
* 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.supercsv.cellprocessor.constraint;
import java.util.HashSet;
import java.util.Set;
import org.supercsv.cellprocessor.CellProcessorAdaptor;
import org.supercsv.cellprocessor.ift.BoolCellProcessor;
import org.supercsv.cellprocessor.ift.CellProcessor;
import org.supercsv.cellprocessor.ift.DateCellProcessor;
import org.supercsv.cellprocessor.ift.DoubleCellProcessor;
import org.supercsv.cellprocessor.ift.LongCellProcessor;
import org.supercsv.cellprocessor.ift.StringCellProcessor;
import org.supercsv.exception.SuperCsvCellProcessorException;
import org.supercsv.exception.SuperCsvConstraintViolationException;
import org.supercsv.util.CsvContext;
/**
* This processor converts the input to a String, and ensures that the input's hash function matches any of a given set
* of hashcodes. Lookup time is O(1).
*
* This constraint is a very efficient way of ensuring constant expressions are present in certain columns of the CSV
* file, such as "BOSS", "EMPLOYEE", or when a column denotes an action to be taken for the input line such as "D"
* (delete), "I" (insert), ...
*
*
* @since 1.50
* @author Kasper B. Graversen
* @author James Bassett
*/
public class RequireHashCode extends CellProcessorAdaptor implements BoolCellProcessor, DateCellProcessor,
DoubleCellProcessor, LongCellProcessor, StringCellProcessor {
private final Set requiredHashCodes = new HashSet();
/**
* Constructs a new RequireHashCode processor, which converts the input to a String, and ensures that the
* input's hash function matches any of a given set of hashcodes.
*
* @param requiredHashcodes
* one or more hashcodes
* @throws NullPointerException
* if requiredHashcodes is null
* @throws IllegalArgumentException
* if requiredHashcodes is empty
*/
public RequireHashCode(final int... requiredHashcodes) {
super();
checkPreconditions(requiredHashcodes);
for( final int hash : requiredHashcodes ) {
this.requiredHashCodes.add(hash);
}
}
/**
* Constructs a new RequireHashCode processor, which converts the input to a String, ensures that the
* input's hash function matches the supplied hashcode, then calls the next processor in the chain.
*
* @param requiredHashcode
* the required hashcode
* @param next
* the next processor in the chain
* @throws NullPointerException
* if next is null
*/
public RequireHashCode(final int requiredHashcode, final CellProcessor next) {
this(new int[] { requiredHashcode }, next);
}
/**
* Constructs a new RequireHashCode processor, which converts the input to a String, ensures that the
* input's hash function matches any of a given set of hashcodes, then calls the next processor in the chain.
*
* @param requiredHashcodes
* one or more hashcodes
* @param next
* the next processor in the chain
* @throws NullPointerException
* if requiredHashcodes or next is null
* @throws IllegalArgumentException
* if requiredHashcodes is empty
*/
public RequireHashCode(final int[] requiredHashcodes, final CellProcessor next) {
super(next);
checkPreconditions(requiredHashcodes);
for( final int hash : requiredHashcodes ) {
this.requiredHashCodes.add(hash);
}
}
/**
* Checks the preconditions for creating a new RequireHashCode processor.
*
* @param requiredHashcodes
* the supplied hashcodes
* @throws NullPointerException
* if requiredHashcodes is null
* @throws IllegalArgumentException
* if requiredHashcodes is empty
*/
private static void checkPreconditions(final int... requiredHashcodes) {
if( requiredHashcodes == null ) {
throw new NullPointerException("requiredHashcodes should not be null");
} else if( requiredHashcodes.length == 0 ) {
throw new IllegalArgumentException("requiredHashcodes should not be empty");
}
}
/**
* {@inheritDoc}
*
* @throws SuperCsvCellProcessorException
* if value is null
* @throws SuperCsvConstraintViolationException
* if value isn't one of the required hash codes
*/
public Object execute(final Object value, final CsvContext context) {
validateInputNotNull(value, context);
int hash = value.hashCode();
if( !requiredHashCodes.contains(hash) ) {
throw new SuperCsvConstraintViolationException(String.format(
"the hashcode of %d for value '%s' does not match any of the required hashcodes", hash, value),
context, this);
}
return next.execute(value, context);
}
}