Class StringConvert


  • public final class StringConvert
    extends java.lang.Object
    Manager for conversion to and from a String, acting as the main client interface.

    Support is provided for conversions based on the StringConverter interface or the ToString and FromString annotations.

    StringConvert is thread-safe with concurrent caches.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static StringConvert INSTANCE
      An immutable global instance.
    • Constructor Summary

      Constructors 
      Constructor Description
      StringConvert()
      Creates a new conversion manager including the JDK converters.
      StringConvert​(boolean includeJdkConverters, StringConverterFactory... factories)
      Creates a new conversion manager.
    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      <T> T convertFromString​(java.lang.Class<T> cls, java.lang.String str)
      Converts the specified object from a String.
      java.lang.String convertToString​(java.lang.Class<?> cls, java.lang.Object object)
      Converts the specified object to a String.
      java.lang.String convertToString​(java.lang.Object object)
      Converts the specified object to a String.
      static StringConvert create()
      Creates a new conversion manager including the extended standard set of converters.
      <T> StringConverter<T> findConverter​(java.lang.Class<T> cls)
      Finds a suitable converter for the type.
      StringConverter<java.lang.Object> findConverterNoGenerics​(java.lang.Class<?> cls)
      Finds a suitable converter for the type with open generics.
      <T> TypedStringConverter<T> findTypedConverter​(java.lang.Class<T> cls)
      Finds a suitable converter for the type.
      TypedStringConverter<java.lang.Object> findTypedConverterNoGenerics​(java.lang.Class<?> cls)
      Finds a suitable converter for the type with open generics.
      boolean isConvertible​(java.lang.Class<?> cls)
      Checks if a suitable converter exists for the type.
      <T> void register​(java.lang.Class<T> cls, StringConverter<T> converter)
      Registers a converter for a specific type.
      <T> void register​(java.lang.Class<T> cls, ToStringConverter<T> toString, FromStringConverter<T> fromString)
      Registers a converter for a specific type using two separate converters.
      void registerFactory​(StringConverterFactory factory)
      Registers a converter factory.
      <T> void registerMethodConstructor​(java.lang.Class<T> cls, java.lang.String toStringMethodName)
      Registers a converter for a specific type by method and constructor.
      <T> void registerMethods​(java.lang.Class<T> cls, java.lang.String toStringMethodName, java.lang.String fromStringMethodName)
      Registers a converter for a specific type by method names.
      java.lang.String toString()
      Returns a simple string representation of the object.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Constructor Detail

      • StringConvert

        public StringConvert()
        Creates a new conversion manager including the JDK converters.

        The convert instance is mutable in a thread-safe manner. Converters may be altered at any time, including the JDK converters. It is strongly recommended to only alter the converters before performing actual conversions.

      • StringConvert

        public StringConvert​(boolean includeJdkConverters,
                             StringConverterFactory... factories)
        Creates a new conversion manager.

        The convert instance is mutable in a thread-safe manner. Converters may be altered at any time, including the JDK converters. It is strongly recommended to only alter the converters before performing actual conversions.

        If specified, the factories will be queried in the order specified.

        Parameters:
        includeJdkConverters - true to include the JDK converters
        factories - optional array of factories to use, not null
    • Method Detail

      • convertToString

        public java.lang.String convertToString​(java.lang.Object object)
        Converts the specified object to a String.

        This uses findConverter(java.lang.Class<T>) to provide the converter.

        Parameters:
        object - the object to convert, null returns null
        Returns:
        the converted string, may be null
        Throws:
        java.lang.RuntimeException - (or subclass) if unable to convert
      • convertToString

        public java.lang.String convertToString​(java.lang.Class<?> cls,
                                                java.lang.Object object)
        Converts the specified object to a String.

        This uses findConverter(java.lang.Class<T>) to provide the converter. The class can be provided to select a more specific converter.

        Parameters:
        cls - the class to convert from, not null
        object - the object to convert, null returns null
        Returns:
        the converted string, may be null
        Throws:
        java.lang.RuntimeException - (or subclass) if unable to convert
      • convertFromString

        public <T> T convertFromString​(java.lang.Class<T> cls,
                                       java.lang.String str)
        Converts the specified object from a String.

        This uses findConverter(java.lang.Class<T>) to provide the converter.

        Type Parameters:
        T - the type to convert to
        Parameters:
        cls - the class to convert to, not null
        str - the string to convert, null returns null
        Returns:
        the converted object, may be null
        Throws:
        java.lang.RuntimeException - (or subclass) if unable to convert
      • isConvertible

        public boolean isConvertible​(java.lang.Class<?> cls)
        Checks if a suitable converter exists for the type.

        This performs the same checks as the findConverter methods. Calling this before findConverter will cache the converter.

        Note that all exceptions, including developer errors are caught and hidden.

        Parameters:
        cls - the class to find a converter for, null returns false
        Returns:
        true if convertible
        Since:
        1.5
      • findConverter

        public <T> StringConverter<T> findConverter​(java.lang.Class<T> cls)
        Finds a suitable converter for the type.

        This returns an instance of StringConverter for the specified class. This is designed for user code where the Class object generics is known.

        The search algorithm first searches the registered converters. It then searches for ToString and FromString annotations on the specified class, class hierarchy or immediate parent interfaces. Finally, it handles Enum instances.

        Type Parameters:
        T - the type of the converter
        Parameters:
        cls - the class to find a converter for, not null
        Returns:
        the converter, not null
        Throws:
        java.lang.RuntimeException - (or subclass) if no converter found
      • findConverterNoGenerics

        public StringConverter<java.lang.Object> findConverterNoGenerics​(java.lang.Class<?> cls)
        Finds a suitable converter for the type with open generics.

        This returns an instance of StringConverter for the specified class. This is designed for framework usage where the Class object generics are unknown'?'. The returned type is declared with Object instead of '?' to allow the ToStringConverter to be invoked.

        The search algorithm first searches the registered converters. It then searches for ToString and FromString annotations on the specified class, class hierarchy or immediate parent interfaces. Finally, it handles Enum instances.

        Parameters:
        cls - the class to find a converter for, not null
        Returns:
        the converter, using Object to avoid generics, not null
        Throws:
        java.lang.RuntimeException - (or subclass) if no converter found
        Since:
        1.5
      • findTypedConverter

        public <T> TypedStringConverter<T> findTypedConverter​(java.lang.Class<T> cls)
        Finds a suitable converter for the type.

        This returns an instance of TypedStringConverter for the specified class. This is designed for user code where the Class object generics is known.

        The search algorithm first searches the registered converters. It then searches for ToString and FromString annotations on the specified class, class hierarchy or immediate parent interfaces. Finally, it handles Enum instances.

        The returned converter may be queried for the effective type of the conversion. This can be used to find the best type to send in a serialized form.

        NOTE: Changing the method return type of findConverter(Class) would be source compatible but not binary compatible. As this is a low-level library, binary compatibility is important, hence the addition of this method.

        Type Parameters:
        T - the type of the converter
        Parameters:
        cls - the class to find a converter for, not null
        Returns:
        the converter, not null
        Throws:
        java.lang.RuntimeException - (or subclass) if no converter found
        Since:
        1.7
      • findTypedConverterNoGenerics

        public TypedStringConverter<java.lang.Object> findTypedConverterNoGenerics​(java.lang.Class<?> cls)
        Finds a suitable converter for the type with open generics.

        This returns an instance of TypedStringConverter for the specified class. This is designed for framework usage where the Class object generics are unknown'?'. The returned type is declared with Object instead of '?' to allow the ToStringConverter to be invoked.

        The search algorithm first searches the registered converters. It then searches for ToString and FromString annotations on the specified class, class hierarchy or immediate parent interfaces. Finally, it handles Enum instances.

        The returned converter may be queried for the effective type of the conversion. This can be used to find the best type to send in a serialized form.

        NOTE: Changing the method return type of findConverterNoGenerics(Class) would be source compatible but not binary compatible. As this is a low-level library, binary compatibility is important, hence the addition of this method.

        Parameters:
        cls - the class to find a converter for, not null
        Returns:
        the converter, using Object to avoid generics, not null
        Throws:
        java.lang.RuntimeException - (or subclass) if no converter found
        Since:
        1.7
      • registerFactory

        public void registerFactory​(StringConverterFactory factory)
        Registers a converter factory.

        This will be registered ahead of all existing factories.

        No new factories may be registered for the global singleton.

        Parameters:
        factory - the converter factory, not null
        Throws:
        java.lang.IllegalStateException - if trying to alter the global singleton
        Since:
        1.5
      • register

        public <T> void register​(java.lang.Class<T> cls,
                                 StringConverter<T> converter)
        Registers a converter for a specific type.

        The converter will be used for subclasses unless overidden.

        No new converters may be registered for the global singleton.

        Type Parameters:
        T - the type of the converter
        Parameters:
        cls - the class to register a converter for, not null
        converter - the String converter, not null
        Throws:
        java.lang.IllegalArgumentException - if the class or converter are null
        java.lang.IllegalStateException - if trying to alter the global singleton
      • register

        public <T> void register​(java.lang.Class<T> cls,
                                 ToStringConverter<T> toString,
                                 FromStringConverter<T> fromString)
        Registers a converter for a specific type using two separate converters.

        This method registers a converter for the specified class. It is primarily intended for use with JDK 1.8 method references or lambdas:

          sc.register(Distance.class, Distance::toString, Distance::parse);
         
        The converter will be used for subclasses unless overidden.

        No new converters may be registered for the global singleton.

        Type Parameters:
        T - the type of the converter
        Parameters:
        cls - the class to register a converter for, not null
        toString - the to String converter, typically a method reference, not null
        fromString - the from String converter, typically a method reference, not null
        Throws:
        java.lang.IllegalArgumentException - if the class or converter are null
        java.lang.IllegalStateException - if trying to alter the global singleton
        Since:
        1.3
      • registerMethods

        public <T> void registerMethods​(java.lang.Class<T> cls,
                                        java.lang.String toStringMethodName,
                                        java.lang.String fromStringMethodName)
        Registers a converter for a specific type by method names.

        This method allows the converter to be used when the target class cannot have annotations added. The two method names must obey the same rules as defined by the annotations ToString and FromString. The converter will be used for subclasses unless overidden.

        No new converters may be registered for the global singleton.

        For example, convert.registerMethods(Distance.class, "toString", "parse");

        Type Parameters:
        T - the type of the converter
        Parameters:
        cls - the class to register a converter for, not null
        toStringMethodName - the name of the method converting to a string, not null
        fromStringMethodName - the name of the method converting from a string, not null
        Throws:
        java.lang.IllegalArgumentException - if the class or method name are null or invalid
        java.lang.IllegalStateException - if trying to alter the global singleton
      • registerMethodConstructor

        public <T> void registerMethodConstructor​(java.lang.Class<T> cls,
                                                  java.lang.String toStringMethodName)
        Registers a converter for a specific type by method and constructor.

        This method allows the converter to be used when the target class cannot have annotations added. The two method name and constructor must obey the same rules as defined by the annotations ToString and FromString. The converter will be used for subclasses unless overidden.

        No new converters may be registered for the global singleton.

        For example, convert.registerMethodConstructor(Distance.class, "toString");

        Type Parameters:
        T - the type of the converter
        Parameters:
        cls - the class to register a converter for, not null
        toStringMethodName - the name of the method converting to a string, not null
        Throws:
        java.lang.IllegalArgumentException - if the class or method name are null or invalid
        java.lang.IllegalStateException - if trying to alter the global singleton
      • toString

        public java.lang.String toString()
        Returns a simple string representation of the object.
        Overrides:
        toString in class java.lang.Object
        Returns:
        the string representation, never null