org.apache.tools.ant.types

Class DataType

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
protected booleanchecked
Are we sure we don't hold circular references?
protected Referenceref
Value to the refid attribute.
Method Summary
protected voidcheckAttributesAllowed()
check that it is ok to set attributes, i.e that no reference is defined
protected voidcheckChildrenAllowed()
check that it is ok to add children, i.e that no reference is defined
protected BuildExceptioncircularReference()
Creates an exception that indicates the user has generated a loop of data types referencing each other.
Objectclone()
protected voiddieOnCircularReference()
Convenience method.
protected voiddieOnCircularReference(Project p)
Convenience method.
protected voiddieOnCircularReference(Stack 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 ObjectgetCheckedRef()
Performs the check for circular references and returns the referenced object.
protected ObjectgetCheckedRef(Project p)
Performs the check for circular references and returns the referenced object.
protected ObjectgetCheckedRef(Class requiredClass, String dataTypeName)
Performs the check for circular references and returns the referenced object.
protected ObjectgetCheckedRef(Class requiredClass, String dataTypeName, Project project)
Performs the check for circular references and returns the referenced object.
protected StringgetDataTypeName()
Gets as descriptive as possible a name used for this datatype instance.
ReferencegetRefid()
get the reference set on this object
static voidinvokeCircularReferenceCheck(DataType dt, Stack stk, Project p)
Allow DataTypes outside org.apache.tools.ant.types to indirectly call dieOnCircularReference on nested DataTypes.
protected booleanisChecked()
The flag that is used to indicate that circular references have been checked.
booleanisReference()
Has the refid attribute of this element been set?
protected BuildExceptionnoChildrenAllowed()
Creates an exception that indicates that this XML element must not have child elements if the refid attribute is set.
protected voidsetChecked(boolean checked)
Set the flag that is used to indicate that circular references have been checked.
voidsetRefid(Reference ref)
Set the value of the refid attribute.
protected BuildExceptiontooManyAttributes()
Creates an exception that indicates that refid has to be the only attribute if it is set.
StringtoString()
Basic DataType toString().

Field Detail

checked

protected boolean checked

Deprecated: since 1.7. The user should not be directly referencing variable. Please use DataType or DataType 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).

ref

protected Reference ref

Deprecated: since 1.7. The user should not be directly referencing variable. Please use DataType instead.

Value to the refid attribute.

Method Detail

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

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

clone

public Object clone()

Returns: a shallow copy of this DataType.

Throws: CloneNotSupportedException if there is a problem.

Since: Ant 1.7

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 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).

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.

getCheckedRef

protected Object getCheckedRef()
Performs the check for circular references and returns the referenced object.

Returns: the dereferenced object.

Throws: BuildException if the reference is invalid (circular ref, wrong class, etc).

Since: Ant 1.7

getCheckedRef

protected Object getCheckedRef(Project p)
Performs the check for circular references and returns the referenced object.

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 Object getCheckedRef(Class requiredClass, String dataTypeName)
Performs the check for circular references and returns the referenced object.

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 Object getCheckedRef(Class 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.

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

getDataTypeName

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

Returns: String name.

getRefid

public Reference getRefid()
get the reference set on this object

Returns: the reference or null

invokeCircularReferenceCheck

public static void invokeCircularReferenceCheck(DataType dt, Stack 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

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

isReference

public boolean isReference()
Has the refid attribute of this element been set?

Returns: true if the refid attribute has been set

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

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

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

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

toString

public String toString()
Basic DataType toString().

Returns: this DataType formatted as a String.