org.apache.uima.resource

## Interface DataResource

- All Superinterfaces:
    Resource

      public interface DataResource
      extends Resource

  `DataResource` is a simple resource that provides access to data. All `DataResource`s will implement the `getInputStream()` method to provide access to their data.

  `DataResource`s may optionally implement `getUrl()`, which would return the URL where the data is located. This may be necessary for some applications, but it is strongly recommended the `getInputStream()` be used whenever possible, because accessing the data directly via the URL does not allow the ResourceManager to assist in caching or sharing of data.

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static String` | `PARAM_RELATIVE_PATH_RESOLVER` Key for the initialization parameter whose value is a reference to the `RelativePathResolver` that this DataResource should use to resolve relative resource URLs.

    - ### Fields inherited from interface org.apache.uima.resource.Resource

      `PARAM_AGGREGATE_SOFA_MAPPINGS, PARAM_CONFIG_MANAGER, PARAM_CONFIG_PARAM_SETTINGS, PARAM_EXTERNAL_OVERRIDE_SETTINGS, PARAM_PERFORMANCE_TUNING_SETTINGS, PARAM_RESOURCE_MANAGER, PARAM_UIMA_CONTEXT`

  - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `equals(Object aObj)` Determines if this `DataResource` is equal to another `DataResource`.
    `InputStream` | `getInputStream()` Gets an `InputStream` to the data.
    `URI` | `getUri()` Gets the URI of the data.
    `URL` | `getUrl()` Gets the URL where the data is stored.
    `int` | `hashCode()` Gest the hash code for this `DataResource`.

    - ### Methods inherited from interface org.apache.uima.resource.Resource

      `destroy, getLogger, getMetaData, getResourceManager, getUimaContext, getUimaContextAdmin, initialize, setLogger`

- - ### Field Detail

    - #### PARAM_RELATIVE_PATH_RESOLVER

          static final String PARAM_RELATIVE_PATH_RESOLVER

      Key for the initialization parameter whose value is a reference to the `RelativePathResolver` that this DataResource should use to resolve relative resource URLs. This value is used as a key in the `aAdditionalParams` Map that is passed to the `Resource.initialize(ResourceSpecifier,Map)` method.
      See Also:
        Constant Field Values

  - ### Method Detail

    - #### getInputStream

          InputStream getInputStream()
                              throws IOException

      Gets an `InputStream` to the data. It is the caller's responsibility to close this input stream when finished with it.
      Returns:
        an InputStream to the data
      Throws:
        `IOException` - if an I/O error occurred when trying to open the stream

    - #### getUri

          URI getUri()

      Gets the URI of the data. In general, this method will return a URI that is equivalent to the URL returned by `getUrl()`. However, in the case where `getUrl()` returns null (indicating no URL available), this method may still return a URI. This can be the case if the URI does not use a standard protocol such as http or file.
      Returns:
        The URI of the data

    - #### getUrl

          URL getUrl()

      Gets the URL where the data is stored. This method may return null if there is no appropriate URL (for example if the data is stored in a relational database). It is recommended that the `getInputStream()` method be used whenever possible - see the class comment for more information.
      Returns:
        the URL where the data is stored, or null if this is not available.

    - #### equals

          boolean equals(Object aObj)

      Determines if this `DataResource` is equal to another `DataResource`. It is important that `DataResource` implementations override this method appropriately, because the `ResourceManager` can make use of this method to determine when cached data can be reused. Two `DataResource`s that are `equal` according to this method will be considered to provide access to the same data; therefore, a common cache can be used.
      Overrides:
        `equals` in class `Object`
      Parameters:
        `aObj` - the object to compare to
      Returns:
        true if and only if `aObj` is a `DataResource` and provides access to the same data as this object.

    - #### hashCode

          int hashCode()

      Gest the hash code for this `DataResource`. As always, if the `equals(Object)` method is overridden, this method should also be overridden. Two objects that are `equal` must have the same hash code.
      Overrides:
        `hashCode` in class `Object`
      Returns:
        the hash code for this object

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