Class 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 simplest example is
<copy todir="dest">
<fileset dir="src">
<modified/>
</fileset>
</copy>
The same example rewritten as CoreSelector with setting the all values (same as defaults are) would be
<copy todir="dest">
<fileset 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>
</fileset>
</copy>
And the same rewritten as CustomSelector would be
<copy todir="dest">
<fileset 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>
</fileset>
</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/mycompany-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
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Nested Class Summary
Nested Classes Modifier and Type Class Description static classModifiedSelector.AlgorithmNameThe enumerated type for algorithm.static classModifiedSelector.CacheNameThe enumerated type for cache.static classModifiedSelector.ComparatorNameThe enumerated type for algorithm. -
Field Summary
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Constructor Summary
Constructors Constructor Description ModifiedSelector()Bean-Constructor. -
Method Summary
Modifier and Type Method Description voidaddClasspath(Path path)Add the classpath.voidaddParam(java.lang.String key, java.lang.Object value)Support for nested <param> tags.voidaddParam(Parameter parameter)Support for nested <param> tags.voidbuildFinished(BuildEvent event)Signals that the last target has finished.voidbuildStarted(BuildEvent event)Signals that a build has started.voidconfigure()Configures this Selector.AlgorithmgetAlgorithm()Get the algorithm type to use.CachegetCache()Get the cache type to use.java.lang.ClassLoadergetClassLoader()Returns and initializes the classloader for this class.java.util.Comparator<? super java.lang.String>getComparator()Get the comparator type to use.booleangetDelayUpdate()Getter for the delay updateintgetModified()Getter for the modified countbooleanisSelected(java.io.File basedir, java.lang.String filename, java.io.File file)Implementation of BaseExtendSelector.isSelected().booleanisSelected(Resource resource)Implementation of ResourceSelector.isSelected().protected <T> TloadClass(java.lang.String classname, java.lang.String msg, java.lang.Class<? extends T> type)Loads the specified class and initializes an object of that class.voidmessageLogged(BuildEvent event)Signals a message logging event.protected voidsaveCache()save the cache filevoidsetAlgorithm(ModifiedSelector.AlgorithmName name)Set the algorithm type to use.voidsetAlgorithmClass(java.lang.String classname)Setter for algorithmClass.voidsetCache(ModifiedSelector.CacheName name)Set the cache type to use.voidsetCacheClass(java.lang.String classname)Setter for cacheClass.voidsetClassLoader(java.lang.ClassLoader loader)Set the used ClassLoader.voidsetComparator(ModifiedSelector.ComparatorName name)Set the comparator type to use.voidsetComparatorClass(java.lang.String classname)Setter for comparatorClass.voidsetDelayUpdate(boolean delayUpdate)Setter for the delay updatevoidsetModified(int modified)Setter for the modified countvoidsetParameters(Parameter... parameters)Defined in org.apache.tools.ant.types.Parameterizable.voidsetSeldirs(boolean seldirs)Support for seldirs attribute.voidsetSelres(boolean newValue)Support for selres attribute.voidsetUpdate(boolean update)Support for update attribute.voidtargetFinished(BuildEvent event)Signals that a target has finished.voidtargetStarted(BuildEvent event)Signals that a target is starting.voidtaskFinished(BuildEvent event)Signals that a task has finished.voidtaskStarted(BuildEvent event)Signals that a task is starting.java.lang.StringtoString()Override Object.toString().protected voidtryToSetAParameter(java.lang.Object obj, java.lang.String name, java.lang.String value)Try to set a value on an object using reflection.voiduseParameter(Parameter parameter)Support for nested<param name="" value=""/>tags.voidverifySettings()Overrides BaseSelector.verifySettings().Methods inherited from class org.apache.tools.ant.types.selectors.BaseSelector
getError, setError, setError, validateMethods inherited from class org.apache.tools.ant.types.DataType
checkAttributesAllowed, checkChildrenAllowed, circularReference, clone, dieOnCircularReference, dieOnCircularReference, dieOnCircularReference, getCheckedRef, getCheckedRef, getCheckedRef, getCheckedRef, getCheckedRef, getDataTypeName, getRefid, invokeCircularReferenceCheck, isChecked, isReference, noChildrenAllowed, pushAndInvokeCircularReferenceCheck, setChecked, setRefid, tooManyAttributesMethods inherited from class org.apache.tools.ant.ProjectComponent
getDescription, getLocation, getProject, log, log, setDescription, setLocation, setProject
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Constructor Details
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ModifiedSelector
public ModifiedSelector()Bean-Constructor.
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Method Details
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verifySettings
public void verifySettings()Overrides BaseSelector.verifySettings().- Overrides:
verifySettingsin classBaseSelector
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configure
public void configure()Configures this Selector. Does this work only once per Selector object.Because some problems while configuring from <custom>Selector the configuration is done in the following order:
- collect the configuration data
- wait for the first isSelected() call
- set the default values
- set values for name pattern '*': update, cache, algorithm, comparator
- 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.
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loadClass
protected <T> T loadClass(java.lang.String classname, java.lang.String msg, java.lang.Class<? extends T> 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.- Type Parameters:
T- desired type- Parameters:
classname- the classnamemsg- the message-part for the BuildExceptiontype- the type to check against- Returns:
- a castable object
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isSelected
Implementation of ResourceSelector.isSelected().- Specified by:
isSelectedin interfaceFileSelector- Specified by:
isSelectedin interfaceResourceSelector- Parameters:
resource- The resource to check- Returns:
- whether the resource is selected
- See Also:
ResourceSelector.isSelected(Resource)
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isSelected
public boolean isSelected(java.io.File basedir, java.lang.String filename, java.io.File file)Implementation of BaseExtendSelector.isSelected().- Specified by:
isSelectedin interfaceFileSelector- Specified by:
isSelectedin classBaseExtendSelector- Parameters:
basedir- as described in BaseExtendSelectorfilename- as described in BaseExtendSelectorfile- as described in BaseExtendSelector- Returns:
- as described in BaseExtendSelector
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saveCache
protected void saveCache()save the cache file -
setAlgorithmClass
public void setAlgorithmClass(java.lang.String classname)Setter for algorithmClass.- Parameters:
classname- new value
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setComparatorClass
public void setComparatorClass(java.lang.String classname)Setter for comparatorClass.- Parameters:
classname- new value
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setCacheClass
public void setCacheClass(java.lang.String classname)Setter for cacheClass.- Parameters:
classname- new value
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setUpdate
public void setUpdate(boolean update)Support for update attribute.- Parameters:
update- new value
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setSeldirs
public void setSeldirs(boolean seldirs)Support for seldirs attribute.- Parameters:
seldirs- new value
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setSelres
public void setSelres(boolean newValue)Support for selres attribute.- Parameters:
newValue- the new value
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getModified
public int getModified()Getter for the modified count- Returns:
- modified count
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setModified
public void setModified(int modified)Setter for the modified count- Parameters:
modified- count
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getDelayUpdate
public boolean getDelayUpdate()Getter for the delay update- Returns:
- true if we should delay for performance
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setDelayUpdate
public void setDelayUpdate(boolean delayUpdate)Setter for the delay update- Parameters:
delayUpdate- true if we should delay for performance
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addClasspath
Add the classpath.- Parameters:
path- the classpath
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getClassLoader
public java.lang.ClassLoader getClassLoader()Returns and initializes the classloader for this class.- Returns:
- the classloader
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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
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addParam
public void addParam(java.lang.String key, java.lang.Object value)Support for nested <param> tags.- Parameters:
key- the key of the parametervalue- the value of the parameter
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addParam
Support for nested <param> tags.- Parameters:
parameter- the parameter object
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setParameters
Defined in org.apache.tools.ant.types.Parameterizable. Overwrite implementation in superclass because only special parameters are valid.- Specified by:
setParametersin interfaceParameterizable- Overrides:
setParametersin classBaseExtendSelector- Parameters:
parameters- the parameters to set.- See Also:
addParam(String,Object)
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useParameter
Support for nested<param name="" value=""/>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
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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 setname- the attributenamevalue- the new value
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toString
public java.lang.String toString()Override Object.toString(). -
buildFinished
Signals that the last target has finished.- Specified by:
buildFinishedin interfaceBuildListener- Parameters:
event- received BuildEvent- See Also:
BuildEvent.getException()
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targetFinished
Signals that a target has finished.- Specified by:
targetFinishedin interfaceBuildListener- Parameters:
event- received BuildEvent- See Also:
BuildEvent.getException()
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taskFinished
Signals that a task has finished.- Specified by:
taskFinishedin interfaceBuildListener- Parameters:
event- received BuildEvent- See Also:
BuildEvent.getException()
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buildStarted
Signals that a build has started.- Specified by:
buildStartedin interfaceBuildListener- Parameters:
event- received BuildEvent
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targetStarted
Signals that a target is starting.- Specified by:
targetStartedin interfaceBuildListener- Parameters:
event- received BuildEvent- See Also:
BuildEvent.getTarget()
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taskStarted
Signals that a task is starting.- Specified by:
taskStartedin interfaceBuildListener- Parameters:
event- received BuildEvent- See Also:
BuildEvent.getTask()
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messageLogged
Signals a message logging event.- Specified by:
messageLoggedin interfaceBuildListener- Parameters:
event- received BuildEvent- See Also:
BuildEvent.getMessage(),BuildEvent.getException(),BuildEvent.getPriority()
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getCache
Get the cache type to use.- Returns:
- the enumerated cache type
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setCache
Set the cache type to use.- Parameters:
name- an enumerated cache type.
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getAlgorithm
Get the algorithm type to use.- Returns:
- the enumerated algorithm type
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setAlgorithm
Set the algorithm type to use.- Parameters:
name- an enumerated algorithm type.
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getComparator
public java.util.Comparator<? super java.lang.String> getComparator()Get the comparator type to use.- Returns:
- the enumerated comparator type
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setComparator
Set the comparator type to use.- Parameters:
name- an enumerated comparator type.
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