EmptyResourceSet (Apache Tomcat 9.0.37 API Documentation)

org.apache.catalina.webresources

## Class EmptyResourceSet

- java.lang.Object
- - org.apache.catalina.util.LifecycleBase
  - - org.apache.catalina.webresources.EmptyResourceSet

- All Implemented Interfaces:
    Lifecycle, WebResourceSet

      public class EmptyResourceSet
      extends LifecycleBase
      implements WebResourceSet

  A `WebResourceSet` implementation that is not backed by a file system and behaves as if it has no resources available. This is primarily used in embedded mode when the web application is configured entirely programmatically and does not use any static resources from the file system.

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from interface org.apache.catalina.Lifecycle

      `Lifecycle.SingleUse`

  - ### Field Summary

    - ### Fields inherited from interface org.apache.catalina.Lifecycle

      `AFTER_DESTROY_EVENT, AFTER_INIT_EVENT, AFTER_START_EVENT, AFTER_STOP_EVENT, BEFORE_DESTROY_EVENT, BEFORE_INIT_EVENT, BEFORE_START_EVENT, BEFORE_STOP_EVENT, CONFIGURE_START_EVENT, CONFIGURE_STOP_EVENT, PERIODIC_EVENT, START_EVENT, STOP_EVENT`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `EmptyResourceSet(WebResourceRoot root)`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected void` | `destroyInternal()` Sub-classes implement this method to perform any instance destruction required.
    `void` | `gc()` Implementations may cache some information to improve performance.
    `URL` | `getBaseUrl()` Obtain the base URL for this set of resources.
    `boolean` | `getClassLoaderOnly()` Should resources returned by this resource set only be included in any results when the lookup is explicitly looking for class loader resources.
    `WebResource` | `getResource(String path)` Obtain the object that represents the resource at the given path.
    `boolean` | `getStaticOnly()` Should resources returned by this resource set only be included in any results when the lookup is explicitly looking for static (non-class loader) resources. i.e. should these resources be excluded from look ups that are explicitly looking for class loader resources.
    `protected void` | `initInternal()` Sub-classes implement this method to perform any instance initialisation required.
    `boolean` | `isReadOnly()` Obtains the current value of the read-only setting for this set of resources.
    `String[]` | `list(String path)` Obtain the list of the names of all of the files and directories located in the specified directory.
    `Set<String>` | `listWebAppPaths(String path)` Obtain the Set of the web applications pathnames of all of the files and directories located in the specified directory.
    `boolean` | `mkdir(String path)` Create a new directory at the given path.
    `void` | `setClassLoaderOnly(boolean classLoaderOnly)`
    `void` | `setReadOnly(boolean readOnly)` Configures whether or not this set of resources is read-only.
    `void` | `setRoot(WebResourceRoot root)`
    `void` | `setStaticOnly(boolean staticOnly)`
    `protected void` | `startInternal()` Sub-classes must ensure that the state is changed to `LifecycleState.STARTING` during the execution of this method.
    `protected void` | `stopInternal()` Sub-classes must ensure that the state is changed to `LifecycleState.STOPPING` during the execution of this method.
    `boolean` | `write(String path, InputStream is, boolean overwrite)` Create a new resource at the requested path using the provided InputStream.

    - ### Methods inherited from class org.apache.catalina.util.LifecycleBase

      `addLifecycleListener, destroy, findLifecycleListeners, fireLifecycleEvent, getState, getStateName, getThrowOnFailure, init, removeLifecycleListener, setState, setState, setThrowOnFailure, start, stop`

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

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

    - ### Methods inherited from interface org.apache.catalina.Lifecycle

      `addLifecycleListener, destroy, findLifecycleListeners, getState, getStateName, init, removeLifecycleListener, start, stop`

- - ### Constructor Detail

    - #### EmptyResourceSet

          public EmptyResourceSet(WebResourceRoot root)

  - ### Method Detail

    - #### getResource

          public WebResource getResource(String path)

      Obtain the object that represents the resource at the given path. Note the resource at that path may not exist.

      This implementation always returns an `EmptyResource`.

      Specified by:
        `getResource` in interface `WebResourceSet`
      Parameters:
        `path` - The path for the resource of interest relative to the root of the web application. It must start with '/'.
      Returns:
        The object that represents the resource at the given path

    - #### list

          public String[] list(String path)

      Obtain the list of the names of all of the files and directories located in the specified directory.

      This implementation always returns an empty array.

      Specified by:
        `list` in interface `WebResourceSet`
      Parameters:
        `path` - The path for the resource of interest relative to the root of the web application. It must start with '/'.
      Returns:
        The list of resources. If path does not refer to a directory then a zero length array will be returned.

    - #### listWebAppPaths

          public Set<String> listWebAppPaths(String path)

      Obtain the Set of the web applications pathnames of all of the files and directories located in the specified directory. Paths representing directories will end with a "/" character.

      This implementation always returns an empty set.

      Specified by:
        `listWebAppPaths` in interface `WebResourceSet`
      Parameters:
        `path` - The path for the resource of interest relative to the root of the web application. It must start with '/'.
      Returns:
        The Set of resources. If path does not refer to a directory then an empty set will be returned.

    - #### mkdir

          public boolean mkdir(String path)

      Create a new directory at the given path.

      This implementation always returns false.

      Specified by:
        `mkdir` in interface `WebResourceSet`
      Parameters:
        `path` - The path for the new resource to create relative to the root of the web application. It must start with '/'.
      Returns:
        `true` if the directory was created, otherwise `false`

    - #### write

          public boolean write(String path,
                               InputStream is,
                               boolean overwrite)

      Create a new resource at the requested path using the provided InputStream.

      This implementation always returns false.

      Specified by:
        `write` in interface `WebResourceSet`
      Parameters:
        `path` - The path to be used for the new Resource. It is relative to the root of the web application and must start with '/'.
        `is` - The InputStream that will provide the content for the new Resource.
        `overwrite` - If `true` and the resource already exists it will be overwritten. If `false` and the resource already exists the write will fail.
      Returns:
        `true` if and only if the new Resource is written

    - #### setRoot

          public void setRoot(WebResourceRoot root)

      Specified by:
        `setRoot` in interface `WebResourceSet`

    - #### getClassLoaderOnly

          public boolean getClassLoaderOnly()

      Description copied from interface: `WebResourceSet`
      Should resources returned by this resource set only be included in any results when the lookup is explicitly looking for class loader resources. i.e. should these resources be excluded from look ups that are explicitly looking for static (non-class loader) resources.
      Specified by:
        `getClassLoaderOnly` in interface `WebResourceSet`
      Returns:
        `true` if these resources should only be used for class loader resource lookups, otherwise `false`

    - #### setClassLoaderOnly

          public void setClassLoaderOnly(boolean classLoaderOnly)

      Specified by:
        `setClassLoaderOnly` in interface `WebResourceSet`

    - #### getStaticOnly

          public boolean getStaticOnly()

      Description copied from interface: `WebResourceSet`
      Should resources returned by this resource set only be included in any results when the lookup is explicitly looking for static (non-class loader) resources. i.e. should these resources be excluded from look ups that are explicitly looking for class loader resources.
      Specified by:
        `getStaticOnly` in interface `WebResourceSet`
      Returns:
        `true` if these resources should only be used for static (non-class loader) resource lookups, otherwise `false`

    - #### setStaticOnly

          public void setStaticOnly(boolean staticOnly)

      Specified by:
        `setStaticOnly` in interface `WebResourceSet`

    - #### getBaseUrl

          public URL getBaseUrl()

      Obtain the base URL for this set of resources. One of the uses of this is to grant read permissions to the resources when running under a security manager.

      This implementation always returns null.

      Specified by:
        `getBaseUrl` in interface `WebResourceSet`
      Returns:
        The base URL for this set of resources

    - #### setReadOnly

          public void setReadOnly(boolean readOnly)

      Configures whether or not this set of resources is read-only.

      Calls to this method will be ignored as this implementation always read only.

      Specified by:
        `setReadOnly` in interface `WebResourceSet`
      Parameters:
        `readOnly` - `true` if this set of resources should be configured to be read-only

    - #### isReadOnly

          public boolean isReadOnly()

      Obtains the current value of the read-only setting for this set of resources.

      This implementation always returns true.

      Specified by:
        `isReadOnly` in interface `WebResourceSet`
      Returns:
        `true` if this set of resources is configured to be read-only, otherwise `false`

    - #### gc

          public void gc()

      Description copied from interface: `WebResourceSet`
      Implementations may cache some information to improve performance. This method triggers the clean-up of those resources.
      Specified by:
        `gc` in interface `WebResourceSet`

    - #### initInternal

          protected void initInternal()
                               throws LifecycleException

      Description copied from class: `LifecycleBase`
      Sub-classes implement this method to perform any instance initialisation required.
      Specified by:
        `initInternal` in class `LifecycleBase`
      Throws:
        `LifecycleException` - If the initialisation fails

    - #### startInternal

          protected void startInternal()
                                throws LifecycleException

      Description copied from class: `LifecycleBase`
      Sub-classes must ensure that the state is changed to `LifecycleState.STARTING` during the execution of this method. Changing state will trigger the `Lifecycle.START_EVENT` event. If a component fails to start it may either throw a `LifecycleException` which will cause it's parent to fail to start or it can place itself in the error state in which case `LifecycleBase.stop()` will be called on the failed component but the parent component will continue to start normally.
      Specified by:
        `startInternal` in class `LifecycleBase`
      Throws:
        `LifecycleException` - Start error occurred

    - #### stopInternal

          protected void stopInternal()
                               throws LifecycleException

      Description copied from class: `LifecycleBase`
      Sub-classes must ensure that the state is changed to `LifecycleState.STOPPING` during the execution of this method. Changing state will trigger the `Lifecycle.STOP_EVENT` event.
      Specified by:
        `stopInternal` in class `LifecycleBase`
      Throws:
        `LifecycleException` - Stop error occurred

    - #### destroyInternal

          protected void destroyInternal()
                                  throws LifecycleException

      Description copied from class: `LifecycleBase`
      Sub-classes implement this method to perform any instance destruction required.
      Specified by:
        `destroyInternal` in class `LifecycleBase`
      Throws:
        `LifecycleException` - If the destruction fails

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