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

# Class DataType

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

All Implemented Interfaces:
  `Cloneable`

Direct Known Subclasses:
  `AbstractFileSet, AbstractResourceCollectionWrapper, AbstractSelectorContainer, AntFilterReader, Archives, Assertions, BaseResourceCollectionContainer, BaseSelector, Compare, Description, ExtensionAdapter, ExtensionSet, FileList, FilterChain, FilterSet, ImageOperation, ImageOperation, IsSigned, MappedResourceCollection, Mapper, Path, PatternSet, PropertySet, RedirectorElement, RegularExpression, Resource, ResourceComparator, ResourceList, Resources, ResourceSelectorContainer, SignedSelector, Substitution, XMLCatalog`

public abstract class DataType extends ProjectComponent implements Cloneable
Base class for those classes that can appear inside the build file as stand alone data types.

This class handles the common description attribute and provides a default implementation for reference handling and checking for circular references that is appropriate for types that can not be nested inside elements of the same type (i.e. <patternset> but not <path>).

- ## Field Summary

  Fields
  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
  `DataType()`

- ## Method Summary

  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`

- ## Field Details

  - ### ref

    @Deprecated protected Reference ref
    Deprecated.
    since 1.7. The user should not be directly referencing variable. Please use `getRefid()` instead.
    Value to the refid attribute.

  - ### checked

    @Deprecated protected boolean checked
    Deprecated.
    since 1.7. The user should not be directly referencing variable. Please use `setChecked(boolean)` or `isChecked()` instead.
    Are we sure we don't hold circular references?

    Subclasses are responsible for setting this value to false if we'd need to investigate this condition (usually because a child element has been added that is a subclass of DataType).

- ## Constructor Details

  - ### DataType

    public DataType()

- ## Method Details

  - ### isReference

    public boolean isReference()
    Has the refid attribute of this element been set?
    Returns:
      true if the refid attribute has been set

  - ### setRefid

    public void setRefid(Reference ref)
    Set the value of the refid attribute.

    Subclasses may need to check whether any other attributes have been set as well or child elements have been created and thus override this method. if they do the must call `super.setRefid`.

    Parameters:
      `ref` - the reference to use

  - ### getDataTypeName

    protected String getDataTypeName()
    Gets as descriptive as possible a name used for this datatype instance.
    Returns:
      `String` name.

  - ### dieOnCircularReference

    protected void dieOnCircularReference()
    Convenience method.
    Since:
      Ant 1.7

  - ### dieOnCircularReference

    protected void dieOnCircularReference(Project p)
    Convenience method.
    Parameters:
      `p` - the Ant Project instance against which to resolve references.
    Since:
      Ant 1.7

  - ### dieOnCircularReference

    protected void dieOnCircularReference(Stack<Object> stack, Project project) throws BuildException
    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).

    If one is included, throw a BuildException created by `circularReference`.

    This implementation is appropriate only for a DataType that cannot hold other DataTypes as children.

    The general contract of this method is that it shouldn't do anything if `checked` is true and set it to true on exit.

    Parameters:
      `stack` - the stack of references to check.
      `project` - the project to use to dereference the references.
    Throws:
      `BuildException` - on error.

  - ### invokeCircularReferenceCheck

    public 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.
    Parameters:
      `dt` - the DataType to check.
      `stk` - the stack of references to check.
      `p` - the project to use to dereference the references.
    Throws:
      `BuildException` - on error.
    Since:
      Ant 1.7

  - ### pushAndInvokeCircularReferenceCheck

    public 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.

    Pushes dt on the stack, runs dieOnCircularReference and pops it again.

    Parameters:
      `dt` - the DataType to check.
      `stk` - the stack of references to check.
      `p` - the project to use to dereference the references.
    Throws:
      `BuildException` - on error.
    Since:
      Ant 1.8.0

  - ### getCheckedRef

    @Deprecated protected <T> T getCheckedRef()
    Deprecated.
    use getCheckedRef(Class)
    Performs the check for circular references and returns the referenced object.
    Type Parameters:
      `T` - required reference type
    Returns:
      the dereferenced object.
    Throws:
      `BuildException` - if the reference is invalid (circular ref, wrong class, etc).
    Since:
      Ant 1.7

  - ### getCheckedRef

    protected <T> T getCheckedRef(Class<T> requiredClass)
    Performs the check for circular references and returns the referenced object.
    Type Parameters:
      `T` - required reference type
    Parameters:
      `requiredClass` - the class that this reference should be a subclass of.
    Returns:
      the dereferenced object.
    Throws:
      `BuildException` - if the reference is invalid (circular ref, wrong class, etc).
    Since:
      Ant 1.10.6

  - ### getCheckedRef

    @Deprecated protected <T> T getCheckedRef(Project p)
    Deprecated.
    use getCheckedRef(Class)
    Performs the check for circular references and returns the referenced object.
    Type Parameters:
      `T` - required reference type
    Parameters:
      `p` - the Ant Project instance against which to resolve references.
    Returns:
      the dereferenced object.
    Throws:
      `BuildException` - if the reference is invalid (circular ref, wrong class, etc).
    Since:
      Ant 1.7

  - ### getCheckedRef

    protected <T> T getCheckedRef(Class<T> requiredClass, String dataTypeName)
    Performs the check for circular references and returns the referenced object.
    Type Parameters:
      `T` - required reference type
    Parameters:
      `requiredClass` - the class that this reference should be a subclass of.
      `dataTypeName` - the name of the datatype that the reference should be (error message use only).
    Returns:
      the dereferenced object.
    Throws:
      `BuildException` - if the reference is invalid (circular ref, wrong class, etc).

  - ### getCheckedRef

    protected <T> T getCheckedRef(Class<T> requiredClass, String dataTypeName, Project project)
    Performs the check for circular references and returns the referenced object. This version allows the fallback Project instance to be specified.
    Type Parameters:
      `T` - required reference type
    Parameters:
      `requiredClass` - the class that this reference should be a subclass of.
      `dataTypeName` - the name of the datatype that the reference should be (error message use only).
      `project` - the fallback Project instance for dereferencing.
    Returns:
      the dereferenced object.
    Throws:
      `BuildException` - if the reference is invalid (circular ref, wrong class, etc), or if `project` is `null`.
    Since:
      Ant 1.7

  - ### tooManyAttributes

    protected BuildException tooManyAttributes()
    Creates an exception that indicates that refid has to be the only attribute if it is set.
    Returns:
      the exception to throw

  - ### noChildrenAllowed

    protected BuildException noChildrenAllowed()
    Creates an exception that indicates that this XML element must not have child elements if the refid attribute is set.
    Returns:
      the exception to throw

  - ### circularReference

    protected BuildException circularReference()
    Creates an exception that indicates the user has generated a loop of data types referencing each other.
    Returns:
      the exception to throw

  - ### isChecked

    protected boolean isChecked()
    The flag that is used to indicate that circular references have been checked.
    Returns:
      true if circular references have been checked

  - ### setChecked

    protected void setChecked(boolean checked)
    Set the flag that is used to indicate that circular references have been checked.
    Parameters:
      `checked` - if true, if circular references have been checked

  - ### getRefid

    public Reference getRefid()
    get the reference set on this object
    Returns:
      the reference or null

  - ### checkAttributesAllowed

    protected void checkAttributesAllowed()
    check that it is ok to set attributes, i.e that no reference is defined
    Throws:
      `BuildException` - if not allowed
    Since:
      Ant 1.6

  - ### checkChildrenAllowed

    protected void checkChildrenAllowed()
    check that it is ok to add children, i.e that no reference is defined
    Throws:
      `BuildException` - if not allowed
    Since:
      Ant 1.6

  - ### toString

    public String toString()
    Basic DataType toString().
    Overrides:
      `toString` in class `Object`
    Returns:
      this DataType formatted as a String.

  - ### clone

    public Object clone() throws CloneNotSupportedException
    Overrides:
      `clone` in class `ProjectComponent`
    Returns:
      a shallow copy of this DataType.
    Throws:
      `CloneNotSupportedException` - if there is a problem.
    Since:
      Ant 1.7