Package org.springframework.messaging.converter

Class AbstractMessageConverter

java.lang.Object
org.springframework.messaging.converter.AbstractMessageConverter
All Implemented Interfaces:
MessageConverter, SmartMessageConverter
Direct Known Subclasses:
AbstractJsonMessageConverter, ByteArrayMessageConverter, MappingJackson2MessageConverter, MarshallingMessageConverter, ProtobufMessageConverter, StringMessageConverter
public abstract class AbstractMessageConverter extends Object implements SmartMessageConverter
Abstract base class for SmartMessageConverter implementations including support for common properties and a partial implementation of the conversion methods, mainly to check if the converter supports the conversion based on the payload class and MIME type.
Since:
4.0
Author:
Rossen Stoyanchev, Sebastien Deleuze, Juergen Hoeller

  • Field Details

    • logger

      protected final Log logger

  • Constructor Details

    • AbstractMessageConverter

      protected AbstractMessageConverter(MimeType supportedMimeType)
      Constructor with a single MIME type.

    • AbstractMessageConverter

      protected AbstractMessageConverter(MimeType... supportedMimeTypes)
      Constructor with multiple MIME types.
      Since:
      5.2.2

    • AbstractMessageConverter

      protected AbstractMessageConverter(Collection<MimeType> supportedMimeTypes)
      Constructor with Collection of MIME types.

  • Method Details

    • getSupportedMimeTypes

      public List<MimeType> getSupportedMimeTypes()
      Return the supported MIME types.

    • addSupportedMimeTypes

      protected void addSupportedMimeTypes(MimeType... supportedMimeTypes)
      Allows subclasses to add more supported mime types.
      Since:
      5.2.2

    • setContentTypeResolver

      public void setContentTypeResolver(@Nullable ContentTypeResolver resolver)
      Configure a ContentTypeResolver for resolving the content type of input messages.

      By default, a DefaultContentTypeResolver instance is used.

      Note: if the resolver is set to null, then strictContentTypeMatch should be false, which is the default, or otherwise this converter will ignore all messages.

    • getContentTypeResolver

      @Nullable public ContentTypeResolver getContentTypeResolver()
      Return the configured ContentTypeResolver.

    • setStrictContentTypeMatch

      public void setStrictContentTypeMatch(boolean strictContentTypeMatch)
      Whether this converter should convert messages for which no content type can be resolved through the configured ContentTypeResolver.

      A converter can be configured to be strict only when a contentTypeResolver is configured and the list of supportedMimeTypes is not empty.

      When this flag is set to true, supportsMimeType(MessageHeaders) will return false if the contentTypeResolver is not defined or if no content-type header is present.

    • isStrictContentTypeMatch

      public boolean isStrictContentTypeMatch()
      Whether content type resolution must produce a value that matches one of the supported MIME types.

    • setSerializedPayloadClass

      public void setSerializedPayloadClass(Class<?> payloadClass)
      Configure the preferred serialization class to use (byte[] or String) when converting an Object payload to a Message.

      The default value is byte[].

      Parameters:
      payloadClass - either byte[] or String

    • getSerializedPayloadClass

      public Class<?> getSerializedPayloadClass()
      Return the configured preferred serialization payload class.

    • fromMessage

      @Nullable public final Object fromMessage(Message<?> message, Class<?> targetClass)
      Description copied from interface: MessageConverter
      Convert the payload of a Message from a serialized form to a typed Object of the specified target class. The MessageHeaders.CONTENT_TYPE header should indicate the MIME type to convert from.

      If the converter does not support the specified media type or cannot perform the conversion, it should return null.

      Specified by:
      fromMessage in interface MessageConverter
      Parameters:
      message - the input message
      targetClass - the target class for the conversion
      Returns:
      the result of the conversion, or null if the converter cannot perform the conversion

    • fromMessage

      @Nullable public final Object fromMessage(Message<?> message, Class<?> targetClass, @Nullable Object conversionHint)
      Description copied from interface: SmartMessageConverter
      A variant of MessageConverter.fromMessage(Message, Class) which takes an extra conversion context as an argument, allowing to take e.g. annotations on a payload parameter into account.
      Specified by:
      fromMessage in interface SmartMessageConverter
      Parameters:
      message - the input message
      targetClass - the target class for the conversion
      conversionHint - an extra object passed to the MessageConverter, e.g. the associated MethodParameter (may be null}
      Returns:
      the result of the conversion, or null if the converter cannot perform the conversion
      See Also:

    • toMessage

      @Nullable public final Message<?> toMessage(Object payload, @Nullable MessageHeaders headers)
      Description copied from interface: MessageConverter
      Create a Message whose payload is the result of converting the given payload Object to serialized form. The optional MessageHeaders parameter may contain a MessageHeaders.CONTENT_TYPE header to specify the target media type for the conversion and it may contain additional headers to be added to the message.

      If the converter does not support the specified media type or cannot perform the conversion, it should return null.

      Specified by:
      toMessage in interface MessageConverter
      Parameters:
      payload - the Object to convert
      headers - optional headers for the message (may be null)
      Returns:
      the new message, or null if the converter does not support the Object type or the target media type

    • toMessage

      @Nullable public final Message<?> toMessage(Object payload, @Nullable MessageHeaders headers, @Nullable Object conversionHint)
      Description copied from interface: SmartMessageConverter
      A variant of MessageConverter.toMessage(Object, MessageHeaders) which takes an extra conversion context as an argument, allowing to take e.g. annotations on a return type into account.
      Specified by:
      toMessage in interface SmartMessageConverter
      Parameters:
      payload - the Object to convert
      headers - optional headers for the message (may be null)
      conversionHint - an extra object passed to the MessageConverter, e.g. the associated MethodParameter (may be null}
      Returns:
      the new message, or null if the converter does not support the Object type or the target media type
      See Also:

    • canConvertFrom

      protected boolean canConvertFrom(Message<?> message, Class<?> targetClass)

    • canConvertTo

      protected boolean canConvertTo(Object payload, @Nullable MessageHeaders headers)

    • supportsMimeType

      protected boolean supportsMimeType(@Nullable MessageHeaders headers)

    • getMimeType

      @Nullable protected MimeType getMimeType(@Nullable MessageHeaders headers)

    • getDefaultContentType

      @Nullable protected MimeType getDefaultContentType(Object payload)
      Return the default content type for the payload. Called when toMessage(Object, MessageHeaders) is invoked without message headers or without a content type header.

      By default, this returns the first element of the supportedMimeTypes, if any. Can be overridden in subclasses.

      Parameters:
      payload - the payload being converted to a message
      Returns:
      the content type, or null if not known

    • supports

      protected abstract boolean supports(Class<?> clazz)
      Whether the given class is supported by this converter.
      Parameters:
      clazz - the class to test for support
      Returns:
      true if supported; false otherwise

    • convertFromInternal

      @Nullable protected Object convertFromInternal(Message<?> message, Class<?> targetClass, @Nullable Object conversionHint)
      Convert the message payload from serialized form to an Object.
      Parameters:
      message - the input message
      targetClass - the target class for the conversion
      conversionHint - an extra object passed to the MessageConverter, e.g. the associated MethodParameter (may be null}
      Returns:
      the result of the conversion, or null if the converter cannot perform the conversion
      Since:
      4.2

    • convertToInternal

      @Nullable protected Object convertToInternal(Object payload, @Nullable MessageHeaders headers, @Nullable Object conversionHint)
      Convert the payload object to serialized form.
      Parameters:
      payload - the Object to convert
      headers - optional headers for the message (may be null)
      conversionHint - an extra object passed to the MessageConverter, e.g. the associated MethodParameter (may be null}
      Returns:
      the resulting payload for the message, or null if the converter cannot perform the conversion
      Since:
      4.2