com.opencsv.bean.CsvBindAndSplitByName Maven / Gradle / Ivy
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/*
* Copyright 2017 Andrew Rucker Jones.
*
* 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 com.opencsv.bean;
import java.lang.annotation.*;
import java.util.Collection;
import java.util.regex.Matcher;
/**
* This annotation interprets one field of the input as a collection that will
* be split up into its components and assigned to a collection-based bean field.
*
* @author Andrew Rucker Jones
* @since 4.2
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface CsvBindAndSplitByName {
/**
* Whether or not the annotated field is required to be present in every
* data set of the input.
* This means that the input cannot be empty. The output after conversion is
* not guaranteed to be non-empty. "Input" means the string from the field
* in the CSV file on reading and the bean member variable on writing.
*
* @return If the field is required to contain information.
*/
boolean required() default false;
/**
* If not specified, the name of the column must be identical to the name
* of the field.
*
* @return The name of the column in the CSV file from which this field
* should be taken.
*/
String column() default "";
/**
* Defines the locale to be used for decoding the argument.
* If not specified, the current default locale is used. The locale must be
* one recognized by {@link java.util.Locale}. Locale conversion is supported
* for the following data types:
* - byte and {@link java.lang.Byte}
* - float and {@link java.lang.Float}
* - double and {@link java.lang.Double}
* - int and {@link java.lang.Integer}
* - long and {@link java.lang.Long}
* - short and {@link java.lang.Short}
* - {@link java.math.BigDecimal}
* - {@link java.math.BigInteger}
* - All time data types supported by {@link com.opencsv.bean.CsvDate}
* The locale must be in a format accepted by
* {@link java.util.Locale#forLanguageTag(java.lang.String)}
* Caution must be exercised with the default locale, for the default
* locale for numerical types does not mean the locale of the running
* program, such as en-US or de-DE, but rather no locale. Numbers
* will be parsed more or less the way the Java compiler would parse them.
* That means, for instance, that thousands separators in long numbers are
* not permitted, even if the locale of the running program would accept
* them. When dealing with locale-sensitive data, it is always best to
* specify the locale explicitly.
*
* @return The locale selected. The default is indicated by an empty string.
*/
String locale() default "";
/**
* Defines a regular expression for splitting the input.
* The input string is split using the value of this attribute and the
* result is put into a collection. The default splits on whitespace.
*
* @return The regular expression used for splitting the input
*/
String splitOn() default "\\s+";
/**
* When writing a collection from a bean, this string will be used to
* separate elements of the collection.
* Defaults to one space.
*
* @return Delimiter between elements for writing a collection
*/
String writeDelimiter() default " ";
/**
* Defines the class used for the collection.
* This must be a specific implementation of a collection, and not an
* interface! The default is set to {@code Collection.class} as a signal to
* use the default for the interface supplied in the bean to be populated.
* The logic for determining which class to instantiate for the
* collection is as follows. In all cases, the implementation must have a
* nullary constructor.
* - If the bean declares a specific implementation instead of the
* associated interface (e.g. {@link java.util.ArrayList} vs.
* {@link java.util.List}), that specific implementation will always be
* used.
* - Otherwise, the implementation named in this field will be used, if it
* is not an interface.
* - If no implementation is specified in this field (i.e. if
* an interface is specified, as is the default), a default is used
* based on the interface of the bean field annotated. These are:
*
- {@link java.util.ArrayList} for {@link java.util.Collection}
* - {@link java.util.ArrayList} for {@link java.util.List}
* - {@link java.util.HashSet} for {@link java.util.Set}
* - {@link java.util.TreeSet} for {@link java.util.SortedSet}
* - {@link java.util.TreeSet} for {@link java.util.NavigableSet}
* - {@link java.util.ArrayDeque} for {@link java.util.Queue}
* - {@link java.util.ArrayDeque} for {@link java.util.Deque}
* - {@link org.apache.commons.collections4.bag.HashBag} for {@link org.apache.commons.collections4.Bag}
* - {@link org.apache.commons.collections4.bag.TreeBag} for {@link org.apache.commons.collections4.SortedBag}
*
* @return A class implementing {@link java.util.Collection}
*/
Class collectionType() default Collection.class;
/**
* Defines what type the elements of the collection should have.
* It is necessary to instantiate elements of the collection, and it is not
* always possible to determine the type of the given collection at runtime.
* A perfect example of this is {@code List}.
*
* @return The type of the collection elements
*/
Class elementType();
/**
* Once the input has been split, a custom converter can optionally be
* specified for conversion of each of the data points.
*
* @return The converter applied to each of the data points extracted from
* the input
* @since 4.3
*/
Class converter() default AbstractCsvConverter.class;
/**
* If this is anything but an empty string, it will be used as a regular
* expression to extract part of the input before conversion to the bean
* field.
* An empty string behaves as if the regular expression {@code ^(.*)$}
* had been specified.
* The regular expression will be compiled and every field of input will
* be passed through it, naturally after the input has been normalized
* (quotations and escape characters removed). The first capture group will
* be extracted, and that string will be passed on to the appropriate
* conversion routine for the bean field in question.
* This makes it possible to easily convert input fields with forms like
* {@code Grade: 94.2} into {@code 94.2}, which can then be converted to a
* floating point bean field, all without writing a custom converter.
* In the case of splitting the input, which is what this annotation
* does, the input will be split before this regular expression is
* then applied to every element of the list resulting from splitting the
* input. This regular expression is not applied to the entire
* input field before splitting.
* The regular expression is applied to the entire string in question
* (i.e. with {@link Matcher#matches()}), instead of just the beginning of
* the string ({@link Matcher#lookingAt()}) or anywhere in the string
* ({@link Matcher#find()}). If it fails to match, the input string is
* passed unchanged to the appropriate conversion routine for the bean
* field. The reason for this is two-fold:
* - The matching may occur against an empty string. If the field is
* not required, this is legitimate, but it's likely the regular expression
* is not written to accommodate this possibility, and it may indeed not be
* at all desirable to.
* - If there is an error in either the regular expression or the input
* that causes the match to fail, there is a good likelihood that the
* subsequent conversion will fail with a
* {@link com.opencsv.exceptions.CsvDataTypeMismatchException} if the
* input is not being converted into a simple string.
* This is the inverse operation of {@link #format()}.
*
* @return A regular expression, the first capture group of which will be
* used for conversion to the bean field
* @since 4.3
*/
String capture() default "";
/**
* If this is anything but an empty string, it will be used as a format
* string for {@link java.lang.String#format(String, Object...)} on
* writing.
* An empty string behaves as if the format string {@code "%s"} had been
* specified.
* The format string, if it is not empty, should contain one and only
* one {@code %s}, which will be replaced by the string value of the bean
* field after conversion. If, however, the bean field is empty, then the
* output will be empty as well, as opposed to passing an empty string to
* this format string and using that as the output.
* This formatting will be applied to every element of the input
* collection separately before writing.
* This is the inverse operation of {@link #capture()}.
*
* @return A format string for writing fields
* @since 4.3
*/
String format() default "";
}