Package org.openstreetmap.josm.data

Class StructUtils

java.lang.Object

org.openstreetmap.josm.data.StructUtils

public final class StructUtils
extends java.lang.Object

Utility methods to convert struct-like classes to a string map and back.

A "struct" is a class that has some fields annotated with StructUtils.StructEntry. Those fields will be respected when converting an object to a Map and back.

Since:

12851

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	StructUtils.SerializeOptions	Options for serializeStruct(T, java.lang.Class<T>, org.openstreetmap.josm.data.StructUtils.SerializeOptions...)
static interface	StructUtils.StructEntry	Annotation used for converting objects to String Maps and vice versa.
static interface	StructUtils.WriteExplicitly	Annotation used for converting objects to String Maps.

Field Summary

Fields

Modifier and Type	Field	Description
private static StringParser	STRING_PARSER

Constructor Summary

Constructors

Modifier	Constructor	Description
private	StructUtils()

Method Summary

Modifier and Type	Method	Description
static <T> T	deserializeStruct(java.util.Map<java.lang.String,java.lang.String> hash, java.lang.Class<T> klass)	Converts a String-Map to an object of a certain class, by comparing map keys to field names of the class and assigning map values to the corresponding fields.
private static <T> java.lang.reflect.Field	getDeclaredFieldInClassOrSuperTypes(java.lang.Class<T> clazz, java.lang.String fieldName)
private static <T> java.lang.reflect.Field[]	getDeclaredFieldsInClassOrSuperTypes(java.lang.Class<T> clazz)
static <T> java.util.List<T>	getListOfStructs(IPreferences preferences, java.lang.String key, java.lang.Class<T> klass)	Get a list of hashes which are represented by a struct-like class.
static <T> java.util.List<T>	getListOfStructs(IPreferences preferences, java.lang.String key, java.util.Collection<T> def, java.lang.Class<T> klass)	same as above, but returns def if nothing was found
private static java.util.Map<java.lang.String,java.lang.String>	mapFromJson(java.lang.String s)
private static java.lang.String	mapToJson(java.util.Map<?,?> map)
private static MultiMap<java.lang.String,java.lang.String>	multiMapFromJson(java.lang.String s)
private static java.lang.String	multiMapToJson(MultiMap<?,?> map)
static <T> boolean	putListOfStructs(IPreferences preferences, java.lang.String key, java.util.Collection<T> val, java.lang.Class<T> klass)	Convenience method that saves a MapListSetting which is provided as a collection of objects.
private static <T> java.util.List<java.util.Map<java.lang.String,java.lang.String>>	serializeListOfStructs(java.util.Collection<T> l, java.lang.Class<T> klass)
static <T> java.util.Map<java.lang.String,java.lang.String>	serializeStruct(T struct, java.lang.Class<T> klass, StructUtils.SerializeOptions... options)	Convert an object to a String Map, by using field names and values as map key and value.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

STRING_PARSER

private static final StringParser STRING_PARSER

Constructor Detail

StructUtils

private StructUtils()

Method Detail

getListOfStructs

public static <T> java.util.List<T> getListOfStructs(IPreferences preferences,
                                                     java.lang.String key,
                                                     java.lang.Class<T> klass)

Get a list of hashes which are represented by a struct-like class. Possible properties are given by fields of the class klass that have the @StructEntry annotation. Default constructor is used to initialize the struct objects, properties then override some of these default values.

Type Parameters:

T - klass type

Parameters:

preferences - preferences to look up the value

key - main preference key

klass - The struct class

Returns:

a list of objects of type T or an empty list if nothing was found

getListOfStructs

public static <T> java.util.List<T> getListOfStructs(IPreferences preferences,
                                                     java.lang.String key,
                                                     java.util.Collection<T> def,
                                                     java.lang.Class<T> klass)

same as above, but returns def if nothing was found

Type Parameters:

T - klass type

Parameters:

preferences - preferences to look up the value

key - main preference key

def - default value

klass - The struct class

Returns:

a list of objects of type T or def if nothing was found

putListOfStructs

public static <T> boolean putListOfStructs(IPreferences preferences,
                                           java.lang.String key,
                                           java.util.Collection<T> val,
                                           java.lang.Class<T> klass)

Convenience method that saves a MapListSetting which is provided as a collection of objects.

Each object is converted to a Map<String, String> using the fields with StructUtils.StructEntry annotation. The field name is the key and the value will be converted to a string.

Considers only fields that have the @StructEntry annotation. In addition it does not write fields with null values. (Thus they are cleared) Default values are given by the field values after default constructor has been called. Fields equal to the default value are not written unless the field has the StructUtils.WriteExplicitly annotation.

Type Parameters:

T - the class,

Parameters:

preferences - the preferences to save to

key - main preference key

val - the list that is supposed to be saved

klass - The struct class

Returns:

true if something has changed

serializeListOfStructs

private static <T> java.util.List<java.util.Map<java.lang.String,java.lang.String>> serializeListOfStructs(java.util.Collection<T> l,
                                                                                                                 java.lang.Class<T> klass)

serializeStruct

public static <T> java.util.Map<java.lang.String,java.lang.String> serializeStruct(T struct,
                                                                                         java.lang.Class<T> klass,
                                                                                         StructUtils.SerializeOptions... options)

Convert an object to a String Map, by using field names and values as map key and value.

The field value is converted to a String.

Only fields with annotation StructUtils.StructEntry are taken into account.

Fields will not be written to the map if the value is null or unchanged (compared to an object created with the no-arg-constructor). The StructUtils.WriteExplicitly annotation overrides this behavior, i.e. the default value will also be written.

Type Parameters:

T - the class of the object struct

Parameters:

struct - the object to be converted

klass - the class T

options - optional serialization options

Returns:

the resulting map (same data content as struct)

deserializeStruct

public static <T> T deserializeStruct(java.util.Map<java.lang.String,java.lang.String> hash,
                                      java.lang.Class<T> klass)

Converts a String-Map to an object of a certain class, by comparing map keys to field names of the class and assigning map values to the corresponding fields.

The map value (a String) is converted to the field type. Supported types are: boolean, Boolean, int, Integer, double, Double, String, Map<String, String> and Map<String, List<String>>.

Only fields with annotation StructUtils.StructEntry are taken into account.

Type Parameters:

T - the class

Parameters:

hash - the string map with initial values

klass - the class T

Returns:

an object of class T, initialized as described above

getDeclaredFieldInClassOrSuperTypes

private static <T> java.lang.reflect.Field getDeclaredFieldInClassOrSuperTypes(java.lang.Class<T> clazz,
                                                                               java.lang.String fieldName)

getDeclaredFieldsInClassOrSuperTypes

private static <T> java.lang.reflect.Field[] getDeclaredFieldsInClassOrSuperTypes(java.lang.Class<T> clazz)

mapToJson

private static java.lang.String mapToJson(java.util.Map<?,?> map)

mapFromJson

private static java.util.Map<java.lang.String,java.lang.String> mapFromJson(java.lang.String s)

multiMapToJson

private static java.lang.String multiMapToJson(MultiMap<?,?> map)

multiMapFromJson

private static MultiMap<java.lang.String,java.lang.String> multiMapFromJson(java.lang.String s)