org.apache.tools.ant.types.selectors.modifiedselector
Class ModifiedSelector

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

All Implemented Interfaces:

java.lang.Cloneable, java.util.EventListener, BuildListener, Parameterizable, ResourceSelector, ExtendFileSelector, FileSelector

public class ModifiedSelector
extends BaseExtendSelector
implements BuildListener, ResourceSelector

Selector class that uses Algorithm, Cache and Comparator for its work. The Algorithm is used for computing a hashvalue for a file. The Comparator decides whether to select or not. The Cache stores the other value for comparison by the Comparator in a persistent manner.

The ModifiedSelector is implemented as a CoreSelector and uses default values for all its attributes therefore the simpliest example is

   <copy todir="dest">
       <filelist dir="src">
           <modified/>
       </filelist>
   </copy>
 

The same example rewritten as CoreSelector with setting the all values (same as defaults are) would be

   <copy todir="dest">
       <filelist dir="src">
           <modified update="true"
                     cache="propertyfile"
                     algorithm="digest"
                     comparator="equal">
               <param name="cache.cachefile"     value="cache.properties"/>
               <param name="algorithm.algorithm" value="MD5"/>
           </modified>
       </filelist>
   </copy>
 

And the same rewritten as CustomSelector would be

   <copy todir="dest">
       <filelist dir="src">
           <custom class="org.apache.tools.ant.type.selectors.ModifiedSelector">
               <param name="update"     value="true"/>
               <param name="cache"      value="propertyfile"/>
               <param name="algorithm"  value="digest"/>
               <param name="comparator" value="equal"/>
               <param name="cache.cachefile"     value="cache.properties"/>
               <param name="algorithm.algorithm" value="MD5"/>
           </custom>
       </filelist>
   </copy>
 

If you want to provide your own interface implementation you can do that via the *classname attributes. If the classes are not on Ant's core classpath, you will have to provide the path via nested <classpath> element, so that the selector can find the classes.

   <modified cacheclassname="com.mycompany.MyCache">
       <classpath>
           <pathelement location="lib/mycompony-antutil.jar"/>
       </classpath>
   </modified>
 

All these three examples copy the files from src to dest using the ModifiedSelector. The ModifiedSelector uses the PropertyfileCache , the DigestAlgorithm and the EqualComparator for its work. The PropertyfileCache stores key-value-pairs in a simple java properties file. The filename is cache.properties. The update flag lets the selector update the values in the cache (and on first call creates the cache). The DigestAlgorithm computes a hashvalue using the java.security.MessageDigest class with its MD5-Algorithm and its standard provider. The new computed hashvalue and the stored one are compared by the EqualComparator which returns 'true' (more correct a value not equals zero (1)) if the values are not the same using simple String comparison.

A useful scenario for this selector is inside a build environment for homepage generation (e.g. with Apache Forrest).

 <target name="generate-and-upload-site">
     <echo> generate the site using forrest </echo>
     <antcall target="site"/>

     <echo> upload the changed files </echo>
     <ftp server="${ftp.server}" userid="${ftp.user}" password="${ftp.pwd}">
         <fileset dir="htdocs/manual">
             <modified/>
         </fileset>
     </ftp>
 </target>
 

Here all changed files are uploaded to the server. The ModifiedSelector saves therefore much upload time.

This selector uses reflection for setting the values of its three interfaces (using org.apache.tools.ant.IntrospectionHelper) therefore no special 'configuration interfaces' has to be implemented by new caches, algorithms or comparators. All present setXX methods can be used. E.g. the DigestAlgorithm can use a specified provider for computing its value. For selecting this there is a setProvider(String providername) method. So you can use a nested <param name="algorithm.provider" value="MyProvider"/>.

Since:

Ant 1.6

Nested Class Summary

static class	ModifiedSelector.AlgorithmName The enumerated type for algorithm.
static class	ModifiedSelector.CacheName The enumerated type for cache.
static class	ModifiedSelector.ComparatorName The enumerated type for algorithm.

Field Summary

Fields inherited from class org.apache.tools.ant.types.selectors.BaseExtendSelector

parameters

Fields inherited from class org.apache.tools.ant.types.DataType

checked, ref

Fields inherited from class org.apache.tools.ant.ProjectComponent

description, location, project

Constructor Summary

ModifiedSelector()
Bean-Constructor.

Method Summary

void	addClasspath(Path path) Add the classpath.
void	addParam(Parameter parameter) Support for nested <param> tags.
void	addParam(java.lang.String key, java.lang.Object value) Support for nested <param> tags.
void	buildFinished(BuildEvent event) Signals that the last target has finished.
void	buildStarted(BuildEvent event) Signals that a build has started.
void	configure() Configures this Selector.
Algorithm	getAlgorithm() Get the algorithm type to use.
Cache	getCache() Get the cache type to use.
java.lang.ClassLoader	getClassLoader() Returns and initializes the classloader for this class.
java.util.Comparator	getComparator() Get the comparator type to use.
boolean	getDelayUpdate() Getter for the delay update
int	getModified() Getter for the modified count
boolean	isSelected(java.io.File basedir, java.lang.String filename, java.io.File file) Implementation of BaseExtendSelector.isSelected().
boolean	isSelected(Resource resource) Implementation of ResourceSelector.isSelected().
protected java.lang.Object	loadClass(java.lang.String classname, java.lang.String msg, java.lang.Class type) Loads the specified class and initializes an object of that class.
void	messageLogged(BuildEvent event) Signals a message logging event.
protected void	saveCache() save the cache file
void	setAlgorithm(ModifiedSelector.AlgorithmName name) Set the algorithm type to use.
void	setAlgorithmClass(java.lang.String classname) Setter for algorithmClass.
void	setCache(ModifiedSelector.CacheName name) Set the cache type to use.
void	setCacheClass(java.lang.String classname) Setter for cacheClass.
void	setClassLoader(java.lang.ClassLoader loader) Set the used ClassLoader.
void	setComparator(ModifiedSelector.ComparatorName name) Set the comparator type to use.
void	setComparatorClass(java.lang.String classname) Setter for comparatorClass.
void	setDelayUpdate(boolean delayUpdate) Setter for the delay update
void	setModified(int modified) Setter for the modified count
void	setParameters(Parameter[] parameters) Defined in org.apache.tools.ant.types.Parameterizable.
void	setSeldirs(boolean seldirs) Support for seldirs attribute.
void	setSelres(boolean newValue) Support for selres attribute.
void	setUpdate(boolean update) Support for update attribute.
void	targetFinished(BuildEvent event) Signals that a target has finished.
void	targetStarted(BuildEvent event) Signals that a target is starting.
void	taskFinished(BuildEvent event) Signals that a task has finished.
void	taskStarted(BuildEvent event) Signals that a task is starting.
java.lang.String	toString() Override Object.toString().
protected void	tryToSetAParameter(java.lang.Object obj, java.lang.String name, java.lang.String value) Try to set a value on an object using reflection.
void	useParameter(Parameter parameter) Support for nested tags.
void	verifySettings() Overrides BaseSelector.verifySettings().

Methods inherited from class org.apache.tools.ant.types.selectors.BaseExtendSelector

getParameters

Methods inherited from class org.apache.tools.ant.types.selectors.BaseSelector

getError, setError, validate

Methods inherited from class org.apache.tools.ant.types.DataType

checkAttributesAllowed, checkChildrenAllowed, circularReference, clone, dieOnCircularReference, dieOnCircularReference, dieOnCircularReference, getCheckedRef, getCheckedRef, getCheckedRef, getCheckedRef, getDataTypeName, getRefid, invokeCircularReferenceCheck, isChecked, isReference, noChildrenAllowed, setChecked, setRefid, tooManyAttributes

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

Constructor Detail

ModifiedSelector

public ModifiedSelector()

Bean-Constructor.

Method Detail

verifySettings

public void verifySettings()

Overrides BaseSelector.verifySettings().

Overrides:

verifySettings in class BaseSelector

configure

public void configure()

Configures this Selector. Does this work only once per Selector object.

Because some problems while configuring from Selector the configuration is done in the following order:

1. collect the configuration data
2. wait for the first isSelected() call
3. set the default values
4. set values for name pattern '*': update, cache, algorithm, comparator
5. set values for name pattern '*.*: cache.cachefile, ...

This configuration algorithm is needed because you don't know the order of arriving config-data. E.g. if you first set the cache.cachefilename and after that the cache itself, the default value for cachefilename is used, because setting the cache implies creating a new Cache instance - with its defaults.

loadClass

protected java.lang.Object loadClass(java.lang.String classname,
                                     java.lang.String msg,
                                     java.lang.Class type)

Loads the specified class and initializes an object of that class. Throws a BuildException using the given message if an error occurs during loading/instantiation or if the object is not from the given type.

Parameters:

classname - the classname

msg - the message-part for the BuildException

type - the type to check against

Returns:

a castable object

isSelected

public boolean isSelected(Resource resource)

Implementation of ResourceSelector.isSelected().

Specified by:

isSelected in interface ResourceSelector

Parameters:

resource - The resource to check

Returns:

whether the resource is selected

See Also:

ResourceSelector.isSelected(Resource)

isSelected

public boolean isSelected(java.io.File basedir,
                          java.lang.String filename,
                          java.io.File file)

Implementation of BaseExtendSelector.isSelected().

Specified by:

isSelected in interface FileSelector

Specified by:

isSelected in class BaseExtendSelector

Parameters:

basedir - as described in BaseExtendSelector

filename - as described in BaseExtendSelector

file - as described in BaseExtendSelector

Returns:

as described in BaseExtendSelector

saveCache

protected void saveCache()

save the cache file

setAlgorithmClass

public void setAlgorithmClass(java.lang.String classname)

Setter for algorithmClass.

Parameters:

classname - new value

setComparatorClass

public void setComparatorClass(java.lang.String classname)

Setter for comparatorClass.

Parameters:

classname - new value

setCacheClass

public void setCacheClass(java.lang.String classname)

Setter for cacheClass.

Parameters:

classname - new value

setUpdate

public void setUpdate(boolean update)

Support for update attribute.

Parameters:

update - new value

setSeldirs

public void setSeldirs(boolean seldirs)

Support for seldirs attribute.

Parameters:

seldirs - new value

setSelres

public void setSelres(boolean newValue)

Support for selres attribute.

Parameters:

newValue - the new value

getModified

public int getModified()

Getter for the modified count

Returns:

modified count

setModified

public void setModified(int modified)

Setter for the modified count

Parameters:

modified - count

getDelayUpdate

public boolean getDelayUpdate()

Getter for the delay update

Returns:

true if we should delay for performance

setDelayUpdate

public void setDelayUpdate(boolean delayUpdate)

Setter for the delay update

Parameters:

delayUpdate - true if we should delay for performance

addClasspath

public void addClasspath(Path path)

Add the classpath.

Parameters:

path - the classpath

getClassLoader

public java.lang.ClassLoader getClassLoader()

Returns and initializes the classloader for this class.

Returns:

the classloader

setClassLoader

public void setClassLoader(java.lang.ClassLoader loader)

Set the used ClassLoader. If you invoke this selector by API (e.g. inside some testcases) the selector will use a different classloader for loading the interface implementations than the caller. Therefore you will get a ClassCastException if you get the implementations from the selector and cast them.

Parameters:

loader - the ClassLoader to use

addParam

public void addParam(java.lang.String key,
                     java.lang.Object value)

Support for nested <param> tags.

Parameters:

key - the key of the parameter

value - the value of the parameter

addParam

public void addParam(Parameter parameter)

Support for nested <param> tags.

Parameters:

parameter - the parameter object

setParameters

public void setParameters(Parameter[] parameters)

Defined in org.apache.tools.ant.types.Parameterizable. Overwrite implementation in superclass because only special parameters are valid.

Specified by:

setParameters in interface Parameterizable

Overrides:

setParameters in class BaseExtendSelector

Parameters:

parameters - the parameters to set.

See Also:

addParam(String,Object).

useParameter

public void useParameter(Parameter parameter)

Support for nested tags. Parameter named cache, algorithm, comparator or update are mapped to the respective set-Method. Parameter which names starts with cache. or algorithm. or comparator. are tried to set on the appropriate object via its set-methods. Other parameters are invalid and an BuildException will be thrown.

Parameters:

parameter - Key and value as parameter object

tryToSetAParameter

protected void tryToSetAParameter(java.lang.Object obj,
                                  java.lang.String name,
                                  java.lang.String value)

Try to set a value on an object using reflection. Helper method for easier access to IntrospectionHelper.setAttribute().

Parameters:

obj - the object on which the attribute should be set

name - the attributename

value - the new value

toString

public java.lang.String toString()

Override Object.toString().

Overrides:

toString in class DataType

Returns:

information about this selector

buildFinished

public void buildFinished(BuildEvent event)

Signals that the last target has finished.

Specified by:

buildFinished in interface BuildListener

Parameters:

event - recieved BuildEvent

See Also:

BuildEvent.getException()

targetFinished

public void targetFinished(BuildEvent event)

Signals that a target has finished.

Specified by:

targetFinished in interface BuildListener

Parameters:

event - recieved BuildEvent

See Also:

BuildEvent.getException()

taskFinished

public void taskFinished(BuildEvent event)

Signals that a task has finished.

Specified by:

taskFinished in interface BuildListener

Parameters:

event - recieved BuildEvent

See Also:

BuildEvent.getException()

buildStarted

public void buildStarted(BuildEvent event)

Signals that a build has started.

Specified by:

buildStarted in interface BuildListener

Parameters:

event - recieved BuildEvent

targetStarted

public void targetStarted(BuildEvent event)

Signals that a target is starting.

Specified by:

targetStarted in interface BuildListener

Parameters:

event - received BuildEvent

See Also:

BuildEvent.getTarget()

taskStarted

public void taskStarted(BuildEvent event)

Signals that a task is starting.

Specified by:

taskStarted in interface BuildListener

Parameters:

event - recieved BuildEvent

See Also:

BuildEvent.getTask()

messageLogged

public void messageLogged(BuildEvent event)

Signals a message logging event.

Specified by:

messageLogged in interface BuildListener

Parameters:

event - recieved BuildEvent

See Also:

BuildEvent.getMessage(), BuildEvent.getException(), BuildEvent.getPriority()

getCache

public Cache getCache()

Get the cache type to use.

Returns:

the enumerated cache type

setCache

public void setCache(ModifiedSelector.CacheName name)

Set the cache type to use.

Parameters:

name - an enumerated cache type.

getAlgorithm

public Algorithm getAlgorithm()

Get the algorithm type to use.

Returns:

the enumerated algorithm type

setAlgorithm

public void setAlgorithm(ModifiedSelector.AlgorithmName name)

Set the algorithm type to use.

Parameters:

name - an enumerated algorithm type.

getComparator

public java.util.Comparator getComparator()

Get the comparator type to use.

Returns:

the enumerated comparator type

setComparator

public void setComparator(ModifiedSelector.ComparatorName name)

Set the comparator type to use.

Parameters:

name - an enumerated comparator type.