ConsumesRequestCondition (Spring Framework 3.2.1.RELEASE API)
Date: 2013-01-24

org.springframework.web.servlet.mvc.condition

## Class ConsumesRequestCondition

- java.lang.Object
- - org.springframework.web.servlet.mvc.condition.AbstractRequestCondition<ConsumesRequestCondition>
  - - org.springframework.web.servlet.mvc.condition.ConsumesRequestCondition

- All Implemented Interfaces:
    RequestCondition<ConsumesRequestCondition>

      public final class ConsumesRequestCondition
      extends AbstractRequestCondition<ConsumesRequestCondition>

  A logical disjunction (' || ') request condition to match a request's 'Content-Type' header to a list of media type expressions. Two kinds of media type expressions are supported, which are described in `RequestMapping.consumes()` and `RequestMapping.headers()` where the header name is 'Content-Type'. Regardless of which syntax is used, the semantics are the same.
  Since:
    3.1
  Author:
    Arjen Poutsma, Rossen Stoyanchev

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `ConsumesRequestCondition(String... consumes)` Creates a new instance from 0 or more "consumes" expressions.
    `ConsumesRequestCondition(String[] consumes, String[] headers)` Creates a new instance with "consumes" and "header" expressions.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `ConsumesRequestCondition` | `combine(ConsumesRequestCondition other)` Returns the "other" instance if it has any expressions; returns "this" instance otherwise.
    `int` | `compareTo(ConsumesRequestCondition other, HttpServletRequest request)` Returns: 0 if the two conditions have the same number of expressions Less than 0 if "this" has more or more specific media type expressions Greater than 0 if "other" has more or more specific media type expressions
    `Set<MediaType>` | `getConsumableMediaTypes()` Returns the media types for this condition excluding negated expressions.
    `protected Collection<org.springframework.web.servlet.mvc.condition.ConsumesRequestCondition.ConsumeMediaTypeExpression>` | `getContent()` Return the discrete items a request condition is composed of.
    `Set<MediaTypeExpression>` | `getExpressions()` Return the contained MediaType expressions.
    `ConsumesRequestCondition` | `getMatchingCondition(HttpServletRequest request)` Checks if any of the contained media type expressions match the given request 'Content-Type' header and returns an instance that is guaranteed to contain matching expressions only.
    `protected String` | `getToStringInfix()` The notation to use when printing discrete items of content.
    `boolean` | `isEmpty()` Whether the condition has any media type expressions.

    - ### Methods inherited from class org.springframework.web.servlet.mvc.condition.AbstractRequestCondition

      `equals, hashCode, toString`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### ConsumesRequestCondition

          public ConsumesRequestCondition(String... consumes)

      Creates a new instance from 0 or more "consumes" expressions.
      Parameters:
        `consumes` - expressions with the syntax described in `RequestMapping.consumes()`; if 0 expressions are provided, the condition will match to every request.

    - #### ConsumesRequestCondition

          public ConsumesRequestCondition(String[] consumes,
                                  String[] headers)

      Creates a new instance with "consumes" and "header" expressions. "Header" expressions where the header name is not 'Content-Type' or have no header value defined are ignored. If 0 expressions are provided in total, the condition will match to every request
      Parameters:
        `consumes` - as described in `RequestMapping.consumes()`
        `headers` - as described in `RequestMapping.headers()`

  - ### Method Detail

    - #### getExpressions

          public Set<MediaTypeExpression> getExpressions()

      Return the contained MediaType expressions.

    - #### getConsumableMediaTypes

          public Set<MediaType> getConsumableMediaTypes()

      Returns the media types for this condition excluding negated expressions.

    - #### isEmpty

          public boolean isEmpty()

      Whether the condition has any media type expressions.

    - #### getContent

          protected Collection<org.springframework.web.servlet.mvc.condition.ConsumesRequestCondition.ConsumeMediaTypeExpression> getContent()

      Description copied from class: `AbstractRequestCondition`
      Return the discrete items a request condition is composed of. For example URL patterns, HTTP request methods, param expressions, etc.
      Specified by:
        `getContent` in class `AbstractRequestCondition<ConsumesRequestCondition>`
      Returns:
        a collection of objects, never `null`

    - #### getToStringInfix

          protected String getToStringInfix()

      Description copied from class: `AbstractRequestCondition`
      The notation to use when printing discrete items of content. For example " || " for URL patterns or " && " for param expressions.
      Specified by:
        `getToStringInfix` in class `AbstractRequestCondition<ConsumesRequestCondition>`

    - #### combine

          public ConsumesRequestCondition combine(ConsumesRequestCondition other)

      Returns the "other" instance if it has any expressions; returns "this" instance otherwise. Practically that means a method-level "consumes" overrides a type-level "consumes" condition.
      Parameters:
        `other` - the condition to combine with.
      Returns:
        a request condition instance that is the result of combining the two condition instances.

    - #### getMatchingCondition

          public ConsumesRequestCondition getMatchingCondition(HttpServletRequest request)

      Checks if any of the contained media type expressions match the given request 'Content-Type' header and returns an instance that is guaranteed to contain matching expressions only. The match is performed via `MediaType.includes(MediaType)`.
      Parameters:
        `request` - the current request
      Returns:
        the same instance if the condition contains no expressions; or a new condition with matching expressions only; or `null` if no expressions match.

    - #### compareTo

          public int compareTo(ConsumesRequestCondition other,
                      HttpServletRequest request)

      Returns:
      - 0 if the two conditions have the same number of expressions
      - Less than 0 if "this" has more or more specific media type expressions
      - Greater than 0 if "other" has more or more specific media type expressions

      It is assumed that both instances have been obtained via `getMatchingCondition(HttpServletRequest)` and each instance contains the matching consumable media type expression only or is otherwise empty.