BaseSelector (Apache Ant API)
Description: declaration: package: org.apache.tools.ant.types.selectors, class: BaseSelector

# Class BaseSelector

java.lang.Object
org.apache.tools.ant.ProjectComponent
org.apache.tools.ant.types.DataType
org.apache.tools.ant.types.selectors.BaseSelector

All Implemented Interfaces:
  `Cloneable, ResourceSelector, FileSelector`

Direct Known Subclasses:
  `BaseExtendSelector, BaseSelectorContainer, ExtendSelector, MappingSelector, PresentSelector, ScriptSelector`

public abstract class BaseSelector extends DataType implements FileSelector
A convenience base class that you can subclass Selectors from. It provides some helpful common behaviour. Note that there is no need for Selectors to inherit from this class, it is only necessary that they implement FileSelector.

Since:
  1.5

- ## Field Summary

  ### Fields inherited from class DataType

  `checked, ref`
  Modifier and Type
  Field
  Description
  `protected boolean`
  `checked`
  Deprecated.
  since 1.7.
  `protected Reference`
  `ref`
  Deprecated.
  since 1.7.

  ### Fields inherited from class ProjectComponent

  `description, location, project`
  Modifier and Type
  Field
  Description
  `protected String`
  `description`
  Deprecated.
  since 1.6.x.
  `protected Location`
  `location`
  Deprecated.
  since 1.6.x.
  `protected Project`
  `project`
  Deprecated.
  since 1.6.x.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `BaseSelector()`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `String`
  `getError()`
  Returns any error messages that have been set.
  `abstract boolean`
  `isSelected(File basedir, String filename, File file)`
  Method that each selector will implement to create their selection behaviour.
  `void`
  `setError(String msg)`
  Allows all selectors to indicate a setup error.
  `void`
  `setError(String msg, Throwable cause)`
  Allows all selectors to indicate a setup error.
  `void`
  `validate()`
  Subclasses can use this to throw the requisite exception in isSelected() in the case of an error condition.
  `void`
  `verifySettings()`
  Subclasses can override this method to provide checking of their state.

  ### Methods inherited from class DataType

  `checkAttributesAllowed, checkChildrenAllowed, circularReference, clone, dieOnCircularReference, dieOnCircularReference, dieOnCircularReference, getCheckedRef, getCheckedRef, getCheckedRef, getCheckedRef, getCheckedRef, getDataTypeName, getRefid, invokeCircularReferenceCheck, isChecked, isReference, noChildrenAllowed, pushAndInvokeCircularReferenceCheck, setChecked, setRefid, tooManyAttributes, toString`
  Modifier and Type
  Method
  Description
  `protected void`
  `checkAttributesAllowed()`
  check that it is ok to set attributes, i.e that no reference is defined
  `protected void`
  `checkChildrenAllowed()`
  check that it is ok to add children, i.e that no reference is defined
  `protected BuildException`
  `circularReference()`
  Creates an exception that indicates the user has generated a loop of data types referencing each other.
  `Object`
  `clone()`
  `protected void`
  `dieOnCircularReference()`
  Convenience method.
  `protected void`
  `dieOnCircularReference(Stack<Object> stack, Project project)`
  Check to see whether any DataType we hold references to is included in the Stack (which holds all DataType instances that directly or indirectly reference this instance, including this instance itself).
  `protected void`
  `dieOnCircularReference(Project p)`
  Convenience method.
  `protected <T> T`
  `getCheckedRef()`
  Deprecated.
  use getCheckedRef(Class)
  `protected <T> T`
  `getCheckedRef(Class<T> requiredClass)`
  Performs the check for circular references and returns the referenced object.
  `protected <T> T`
  `getCheckedRef(Class<T> requiredClass, String dataTypeName)`
  Performs the check for circular references and returns the referenced object.
  `protected <T> T`
  `getCheckedRef(Class<T> requiredClass, String dataTypeName, Project project)`
  Performs the check for circular references and returns the referenced object.
  `protected <T> T`
  `getCheckedRef(Project p)`
  Deprecated.
  use getCheckedRef(Class)
  `protected String`
  `getDataTypeName()`
  Gets as descriptive as possible a name used for this datatype instance.
  `Reference`
  `getRefid()`
  get the reference set on this object
  `static void`
  `invokeCircularReferenceCheck(DataType dt, Stack<Object> stk, Project p)`
  Allow DataTypes outside org.apache.tools.ant.types to indirectly call dieOnCircularReference on nested DataTypes.
  `protected boolean`
  `isChecked()`
  The flag that is used to indicate that circular references have been checked.
  `boolean`
  `isReference()`
  Has the refid attribute of this element been set?
  `protected BuildException`
  `noChildrenAllowed()`
  Creates an exception that indicates that this XML element must not have child elements if the refid attribute is set.
  `static void`
  `pushAndInvokeCircularReferenceCheck(DataType dt, Stack<Object> stk, Project p)`
  Allow DataTypes outside org.apache.tools.ant.types to indirectly call dieOnCircularReference on nested DataTypes.
  `protected void`
  `setChecked(boolean checked)`
  Set the flag that is used to indicate that circular references have been checked.
  `void`
  `setRefid(Reference ref)`
  Set the value of the refid attribute.
  `protected BuildException`
  `tooManyAttributes()`
  Creates an exception that indicates that refid has to be the only attribute if it is set.
  `String`
  `toString()`
  Basic DataType toString().

  ### Methods inherited from class ProjectComponent

  `getDescription, getLocation, getProject, log, log, setDescription, setLocation, setProject`
  Modifier and Type
  Method
  Description
  `String`
  `getDescription()`
  Returns the description of the current action.
  `Location`
  `getLocation()`
  Returns the file/location where this task was defined.
  `Project`
  `getProject()`
  Returns the project to which this component belongs.
  `void`
  `log(String msg)`
  Logs a message with the default (INFO) priority.
  `void`
  `log(String msg, int msgLevel)`
  Logs a message with the given priority.
  `void`
  `setDescription(String desc)`
  Sets a description of the current action.
  `void`
  `setLocation(Location location)`
  Sets the file/location where this task was defined.
  `void`
  `setProject(Project project)`
  Sets the project object of this component.

  ### Methods inherited from class Object

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

  ### Methods inherited from interface FileSelector

  `isSelected`
  Modifier and Type
  Method
  Description
  `default boolean`
  `isSelected(Resource r)`
  Implement a basic `Resource` selection that delegates to this `FileSelector`.

- ## Constructor Details

  - ### BaseSelector

    public BaseSelector()

- ## Method Details

  - ### setError

    public void setError(String msg)
    Allows all selectors to indicate a setup error. Note that only the first error message is recorded.
    Parameters:
      `msg` - The error message any BuildException should throw.

  - ### setError

    public void setError(String msg, Throwable cause)
    Allows all selectors to indicate a setup error. Note that only the first error message is recorded.
    Parameters:
      `msg` - The error message any BuildException should throw.
      `cause` - Throwable

  - ### getError

    public String getError()
    Returns any error messages that have been set.
    Returns:
      the error condition

  - ### verifySettings

    public void verifySettings()

    Subclasses can override this method to provide checking of their state. So long as they call validate() from isSelected(), this will be called automatically (unless they override validate()).

    Implementations should check for incorrect settings and call setError() as necessary.

  - ### validate

    public void validate()
    Subclasses can use this to throw the requisite exception in isSelected() in the case of an error condition.

  - ### isSelected

    public abstract boolean isSelected(File basedir, String filename, File file)
    Method that each selector will implement to create their selection behaviour. If there is a problem with the setup of a selector, it can throw a BuildException to indicate the problem.
    Specified by:
      `isSelected` in interface `FileSelector`
    Parameters:
      `basedir` - A java.io.File object for the base directory
      `filename` - The name of the file to check
      `file` - A File object for this filename
    Returns:
      whether the file should be selected or not