Package org.eclipse.core.expressions

Class PropertyTester

  • All Implemented Interfaces:
    IPropertyTester
    public abstract class PropertyTester
extends java.lang.Object
implements IPropertyTester
    Abstract superclass of all property testers. Implementation classes of the extension point org.eclipse.core.expresssions.propertyTesters must extend PropertyTester.

    A property tester implements the property tests enumerated in the property tester extension point. For the following property test extension 

       <propertyTester
         namespace="org.eclipse.jdt.core"
       id="org.eclipse.jdt.core.IPackageFragmentTester"
       properties="isDefaultPackage"
       type="org.eclipse.jdt.core.IPackageFragment"
       class="org.eclipse.demo.MyPackageFragmentTester">
     </propertyTester>
    the corresponding implementation class looks like: 
       public class MyPackageFragmentTester extends PropertyTester {
       public boolean test(Object receiver, String property, Object[] args, Object expectedValue) {
           IPackageFragment fragment= (IPackageFragment)receiver;
                 if ("isDefaultPackage".equals(property)) {
               return expectedValue == null
                ? fragment.isDefaultPackage()
                : fragment.isDefaultPackage() == ((Boolean)expectedValue).booleanValue();
           }
           Assert.isTrue(false);
           return false;
       }
   }
    The property can then be used in a test expression as follows: 
       <instanceof value="org.eclipse.core.IPackageFragment"/>
   <test property="org.eclipse.jdt.core.isDefaultPackage"/>

    There is no guarantee that the same instance of a property tester is used to handle <test property="..."/> requests. So property testers should always be implemented in a stateless fashion.

    Since:
    3.0

    • Constructor Summary

      Constructors 
      Constructor Description
      PropertyTester()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean handles​(java.lang.String namespace, java.lang.String property)
      Returns whether the property tester can handle the given property or not.
      IPropertyTester instantiate()
      Loads the implementation class for this property tester and returns an instance of this class.
      org.eclipse.core.internal.expressions.PropertyTesterDescriptor internalCreateDescriptor()
      Note: this method is for internal use only.
      void internalInitialize​(org.eclipse.core.internal.expressions.PropertyTesterDescriptor descriptor)
      Initialize the property tester with the given name space and property.
      boolean isDeclaringPluginActive()
      Returns true if the implementation class of this property tester can be loaded.
      boolean isInstantiated()
      Returns whether the implementation class for this property tester is loaded or not.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • PropertyTester

        public PropertyTester()

    • Method Detail

      • internalInitialize

        public final void internalInitialize​(org.eclipse.core.internal.expressions.PropertyTesterDescriptor descriptor)
        Initialize the property tester with the given name space and property.

        Note: this method is for internal use only. Clients must not call this method.

        Parameters:
        descriptor - the descriptor object for this tester
        Restriction:
        This method is not intended to be referenced by clients.

      • internalCreateDescriptor

        public final org.eclipse.core.internal.expressions.PropertyTesterDescriptor internalCreateDescriptor()
        Note: this method is for internal use only. Clients must not call this method.
        Returns:
        the property tester descriptor
        Restriction:
        This method is not intended to be referenced by clients.

      • handles

        public final boolean handles​(java.lang.String namespace,
                             java.lang.String property)
        Description copied from interface: IPropertyTester
        Returns whether the property tester can handle the given property or not.
        Specified by:
        handles in interface IPropertyTester
        Parameters:
        namespace - the name space to be considered
        property - the property to test
        Returns:
        true if the tester provides an implementation for the given property; otherwise false is returned

      • isInstantiated

        public final boolean isInstantiated()
        Description copied from interface: IPropertyTester
        Returns whether the implementation class for this property tester is loaded or not.
        Specified by:
        isInstantiated in interface IPropertyTester
        Returns:
        trueif the implementation class is loaded; false otherwise

      • isDeclaringPluginActive

        public boolean isDeclaringPluginActive()
        Description copied from interface: IPropertyTester
        Returns true if the implementation class of this property tester can be loaded. This is the case if the plug-in providing the implementation class is active. Returns false otherwise.
        Specified by:
        isDeclaringPluginActive in interface IPropertyTester
        Returns:
        whether the implementation class can be loaded or not

      • instantiate

        public final IPropertyTester instantiate()
        Description copied from interface: IPropertyTester
        Loads the implementation class for this property tester and returns an instance of this class.
        Specified by:
        instantiate in interface IPropertyTester
        Returns:
        an instance of the implementation class for this property tester