Interface MappingStrategy<T>
- Type Parameters:
T
- Type of object you are converting the data to.
- All Known Implementing Classes:
AbstractMappingStrategy
,ColumnPositionMappingStrategy
,FuzzyMappingStrategy
,HeaderColumnNameMappingStrategy
,HeaderColumnNameTranslateMappingStrategy
,HeaderNameBaseMappingStrategy
Any implementing class must be thread-safe. Specifically, the following methods must be thread-safe:
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Method Summary
Modifier and TypeMethodDescriptionvoid
captureHeader
(CSVReader reader) Implementation of this method can grab the header line before parsing begins to use to map columns to bean properties.String[]
generateHeader
(T bean) Implementations of this method must return an array of column headers based on the contents of the mapping strategy.default void
ignoreFields
(org.apache.commons.collections4.MultiValuedMap<Class<?>, Field> fields) When processing a bean for reading or writing, ignore the given fields from the given classes completely, including all annotations and requirements.default boolean
Deprecated.This is simply no longer necessary.populateNewBean
(String[] line) Takes a line of input from a CSV file and creates a bean out of it.default void
setErrorLocale
(Locale errorLocale) Sets the locale for all error messages.default void
setProfile
(String profile) Sets the profile this mapping strategy will use when configuring bean fields.void
Sets the class type that is being mapped.String[]
transmuteBean
(T bean) Transmutes a bean instance into an array ofString
s to be written to a CSV file.
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Method Details
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captureHeader
Implementation of this method can grab the header line before parsing begins to use to map columns to bean properties.- Parameters:
reader
- The CSVReader to use for header parsing- Throws:
IOException
- If parsing failsCsvRequiredFieldEmptyException
- If a field is required, but the header or column position for the field is not present in the input
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generateHeader
Implementations of this method must return an array of column headers based on the contents of the mapping strategy. If no header can or should be generated, an array of zero length must be returned, and notnull
.- Parameters:
bean
- One fully populated bean from which the header can be derived. This is important in the face of joining and splitting. If we have a MultiValuedMap as a field that is the target for a join on reading, that same field must be split into multiple columns on writing. Since the joining is done via regular expressions, it is impossible for opencsv to know what the column names are supposed to be on writing unless this bean includes a fully populated map.- Returns:
- An array of column names for a header. This may be an empty array
if no header should be written, but it must not be
null
. - Throws:
CsvRequiredFieldEmptyException
- If a required header is missing while attempting to write. Since every other header is hard-wired through the bean fields and their associated annotations, this can only happen with multi-valued fields.- Since:
- 3.9
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isAnnotationDriven
Deprecated.This is simply no longer necessary.Determines whether the mapping strategy is driven by annotations.- Returns:
- Whether the mapping strategy is driven by annotations
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populateNewBean
T populateNewBean(String[] line) throws CsvBeanIntrospectionException, CsvFieldAssignmentException, CsvChainedException Takes a line of input from a CSV file and creates a bean out of it.- Parameters:
line
- A line of input returned fromCSVReader
- Returns:
- A bean containing the converted information from the input
- Throws:
CsvBeanIntrospectionException
- Generally, if some part of the bean cannot be accessed and used as neededCsvFieldAssignmentException
- A more specific subclass of this exception is thrown for any problem decoding and assigning a field of the input to a bean fieldCsvChainedException
- If multiple exceptions are thrown for the same input line- Since:
- 4.2
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setErrorLocale
Sets the locale for all error messages. The default implementation does nothing, as it is expected that most implementations of this interface will not support multiple languages.- Parameters:
errorLocale
- Locale for error messages. If null, the default locale is used.- Since:
- 4.0
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setType
Sets the class type that is being mapped. May perform additional initialization tasks. If instantiating a mapping strategy, this method should be called after any other initialization, for example a call tosetErrorLocale(Locale)
orsetProfile(String)
.- Parameters:
type
- Class type.- Throws:
CsvBadConverterException
- If a field in the bean is annotated with a custom converter that cannot be initialized. If you are not using custom converters that you have written yourself, it should be safe to catch this exception and ignore it.
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setProfile
Sets the profile this mapping strategy will use when configuring bean fields.The default implementation throws
UnsupportedOperationException
.- Parameters:
profile
- The profile to use- Since:
- 5.4
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ignoreFields
default void ignoreFields(org.apache.commons.collections4.MultiValuedMap<Class<?>, Field> fields) throws IllegalArgumentExceptionWhen processing a bean for reading or writing, ignore the given fields from the given classes completely, including all annotations and requirements. This method has two compelling applications:
- If you are not able to modify the source code of the beans you use, or
- If you use a mapping strategy without annotations and want to exclude a small number of fields from a bean with a large number of fields.
Calling this method overwrites the fields passed in from any previous calls. It is legal to call this method before calling
setType(Class)
, and it may be more efficient to do so.Caution must be exercised with this method when letting opencsv automatically determine the mapping strategy. When a field is ignored, opencsv pretends it does not exist at all. If, for instance, all fields annotated with opencsv binding annotations are ignored, opencsv will automatically switch to
HeaderColumnNameMappingStrategy
and assume header names exactly match field names.An implementation of this interface is not required to implement this method. The default implementation throws
UnsupportedOperationException
.- Parameters:
fields
- All fields to be ignored, mapped from the classes of which they are members. These are the classes as opencsv encounters them, not necessarily the declaring classes if any fields are inherited. May benull
.- Throws:
IllegalArgumentException
- If any entry in the map has anull
key, anull
value, or if the value is not a field in the class represented by the key- Since:
- 5.0
- See Also:
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transmuteBean
Transmutes a bean instance into an array ofString
s to be written to a CSV file.- Parameters:
bean
- The bean to be transmuted- Returns:
- The converted values of the bean fields in the correct order,
ready to be passed to a
CSVWriter
- Throws:
CsvFieldAssignmentException
- A more specific subclass of this exception is thrown for any problem decoding and assigning a field of the input to a bean fieldCsvChainedException
- If multiple exceptions are thrown for the same input line
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