Interface Asset

All Known Implementing Classes:
AbstractAsset, UrlAsset

public interface Asset
An Asset is any kind of resource that can be exposed to the client web browser. Although quite often an Asset is a resource in a web application's context folder, within Tapestry, Assets may also be resources on the classpath (i.e., packaged inside JARs). An Asset's toString() will return the URL for the resource (the same value as toClientURL()). Release 5.1.0.0 introduced org.apache.tapestry5.Asset2, which extends this interface with an additional method. Release 5.7.0 merged Asset2 into Asset and Asset2 got removed.
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  • Method Summary

    Modifier and Type
    Method
    Description
    Returns the underlying Resource for the Asset.
    default boolean
    Returns true if the Asset is invariant (meaning that it returns the same value from toClientURL() at all times).
    Returns a URL that can be passed, unchanged, to the client in order for it to access the resource.
  • Method Details

    • toClientURL

      Returns a URL that can be passed, unchanged, to the client in order for it to access the resource. The same value is returned from toString(). Tapestry's built-in asset types (context and classpath) always incorporate a checksum as part of the path, and alternate implementations are encouraged to do so as well. In addition, Tapestry ensures that context and classpath assets have a far-future expires header (to ensure aggressive caching by the client). Note that starting in Tapestry 5.4, it is expected that Asset instances recognize when the underlying Resource's content has changed, and update the clientURL to reflect the new content's checksum. This wasn't an issue in earlier releases where the clientURL incorporated a version number. Finally, starting in 5.4, this value will often be variant: the exact URL returned will depend on whether the underlying resource content is compressable, whether the current Request supports compression.
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    • getResource

      Returns the underlying Resource for the Asset.
    • isInvariant

      default boolean isInvariant()
      Returns true if the Asset is invariant (meaning that it returns the same value from toClientURL() at all times). Most Assets are invariant. Assets that are used as binding values will be cached more aggressively by Tapestry if they are invariant. This default implementation returns false
      Returns:
      true if invariant
      Since:
      5.1.0.0 (in Asset2), 5.7.0 (in Asset).
      See Also: