Package org.apache.tomcat.util.digester

## Class SystemPropertySource

- java.lang.Object
- - org.apache.tomcat.util.digester.SystemPropertySource

- All Implemented Interfaces:
    `IntrospectionUtils.PropertySource`, `IntrospectionUtils.SecurePropertySource`

      public class SystemPropertySource
      extends java.lang.Object
      implements IntrospectionUtils.SecurePropertySource

  A `IntrospectionUtils.SecurePropertySource` that uses system properties to resolve expressions. This property source is always active by default.
  See Also:
    `Digester`

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `SystemPropertySource()` |

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `java.lang.String` | `getProperty​(java.lang.String key)` |
    `java.lang.String` | `getProperty​(java.lang.String key, java.lang.ClassLoader classLoader)` | Obtain a property value, checking that code associated with the provided class loader has permission to access the property.

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

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

- - ### Constructor Detail

    - #### SystemPropertySource

          public SystemPropertySource()

  - ### Method Detail

    - #### getProperty

          public java.lang.String getProperty​(java.lang.String key)

      Specified by:
        `getProperty` in interface `IntrospectionUtils.PropertySource`

    - #### getProperty

          public java.lang.String getProperty​(java.lang.String key,
                                              java.lang.ClassLoader classLoader)

      Description copied from interface: `IntrospectionUtils.SecurePropertySource`
      Obtain a property value, checking that code associated with the provided class loader has permission to access the property. If the `classLoader` is `null` or if `classLoader` does not implement `PermissionCheck` then the property value will be looked up without a call to `PermissionCheck.check(java.security.Permission)`
      Specified by:
        `getProperty` in interface `IntrospectionUtils.SecurePropertySource`
      Parameters:
        `key` - The key of the requested property
        `classLoader` - The class loader associated with the code that trigger the property lookup
      Returns:
        The property value or `null` if it could not be found or if `PermissionCheck.check(java.security.Permission)` fails