Package org.apache.tools.ant.types

# 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 org.apache.tools.ant.ProjectComponent

`description, location, project`

## 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 org.apache.tools.ant.ProjectComponent

`getDescription, getLocation, getProject, log, log, setDescription, setLocation, setProject`

### Methods inherited from class java.lang.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