Package com.puppycrawl.tools.checkstyle

Class PropertyCacheFile

java.lang.Object

com.puppycrawl.tools.checkstyle.PropertyCacheFile

public final class PropertyCacheFile
extends Object

This class maintains a persistent(on file-system) store of the files that have checked ok(no validation events) and their associated timestamp. It is used to optimize Checkstyle between few launches. It is mostly useful for plugin and extensions of Checkstyle. It uses a property file for storage. A hashcode of the Configuration is stored in the cache file to ensure the cache is invalidated when the configuration has changed.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	PropertyCacheFile.ExternalResource	Class which represents external resource.

Field Summary

Fields

Modifier and Type	Field	Description
private static int	BASE_16	Default number for base 16 encoding.
private static byte[]	BUFFER	Default buffer for reading from streams.
private static int	BUFFER_SIZE	Size of default byte array for buffer.
private Configuration	config	Configuration object.
static String	CONFIG_HASH_KEY	The property key to use for storing the hashcode of the configuration.
private String	configHash	Generated configuration hash.
private Properties	details	The details on files.
static String	EXTERNAL_RESOURCE_KEY_PREFIX	The property prefix to use for storing the hashcode of an external resource.
private String	fileName	File name of cache.

Constructor Summary

Constructors

Constructor	Description
PropertyCacheFile(Configuration config, String fileName)	Creates a new PropertyCacheFile instance.

Method Summary

Modifier and Type	Method	Description
private boolean	areExternalResourcesChanged(Set<PropertyCacheFile.ExternalResource> resources)	Checks whether the contents of external configuration resources were changed.
private void	fillCacheWithExternalResources(Set<PropertyCacheFile.ExternalResource> externalResources)	Fills cache with a set of PropertyCacheFile.ExternalResource.
String	get(String name)	Retrieves the hash of a specific file.
private static String	getHashCodeBasedOnObjectContent(Serializable object)	Calculates the hashcode for the serializable object based on its content.
boolean	isInCache(String uncheckedFileName, long timestamp)	Checks that file is in cache.
private boolean	isResourceChanged(PropertyCacheFile.ExternalResource resource)	Checks whether the resource is changed.
private boolean	isResourceLocationInCache(String location)	Checks whether resource location is in cache.
void	load()	Load cached values from file.
private static byte[]	loadExternalResource(String location)	Loads the content of external resource.
private static Set<PropertyCacheFile.ExternalResource>	loadExternalResources(Set<String> resourceLocations)	Loads a set of PropertyCacheFile.ExternalResource based on their locations.
void	persist()	Cleans up the object and updates the cache file.
void	put(String checkedFileName, long timestamp)	Records that a file checked ok.
void	putExternalResources(Set<String> locations)	Puts external resources in cache.
void	remove(String checkedFileName)	Removed a specific file from the cache.
void	reset()	Resets the cache to be empty except for the configuration hash.
private static void	serialize(Serializable object, OutputStream outputStream)	Serializes object to output stream.
private static byte[]	toByteArray(InputStream stream)	Reads all the contents of an input stream and returns it as a byte array.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CONFIG_HASH_KEY

public static final String CONFIG_HASH_KEY

The property key to use for storing the hashcode of the configuration. To avoid name clashes with the files that are checked the key is chosen in such a way that it cannot be a valid file name.

See Also:

Constant Field Values

EXTERNAL_RESOURCE_KEY_PREFIX

public static final String EXTERNAL_RESOURCE_KEY_PREFIX

The property prefix to use for storing the hashcode of an external resource. To avoid name clashes with the files that are checked the prefix is chosen in such a way that it cannot be a valid file name and makes it clear it is a resource.

See Also:

Constant Field Values

BUFFER_SIZE

private static final int BUFFER_SIZE

Size of default byte array for buffer.

See Also:

Constant Field Values

BUFFER

private static final byte[] BUFFER

Default buffer for reading from streams.

BASE_16

private static final int BASE_16

Default number for base 16 encoding.

See Also:

Constant Field Values

details

private final Properties details

The details on files.

config

private final Configuration config

Configuration object.

fileName

private final String fileName

File name of cache.

configHash

private String configHash

Generated configuration hash.

Constructor Detail

PropertyCacheFile

public PropertyCacheFile(Configuration config,
                         String fileName)

Creates a new PropertyCacheFile instance.

Parameters:

config - the current configuration, not null

fileName - the cache file

Throws:

IllegalArgumentException - when either arguments are null

Method Detail

load

public void load()
          throws IOException

Load cached values from file.

Throws:

IOException - when there is a problems with file read

persist

public void persist()
             throws IOException

Cleans up the object and updates the cache file.

Throws:

IOException - when there is a problems with file save

reset

public void reset()

Resets the cache to be empty except for the configuration hash.

isInCache

public boolean isInCache(String uncheckedFileName,
                         long timestamp)

Checks that file is in cache.

Parameters:

uncheckedFileName - the file to check

timestamp - the timestamp of the file to check

Returns:

whether the specified file has already been checked ok

put

public void put(String checkedFileName,
                long timestamp)

Records that a file checked ok.

Parameters:

checkedFileName - name of the file that checked ok

timestamp - the timestamp of the file

get

public String get(String name)

Retrieves the hash of a specific file.

Parameters:

name - The name of the file to retrieve.

Returns:

The has of the file or null.

remove

public void remove(String checkedFileName)

Removed a specific file from the cache.

Parameters:

checkedFileName - The name of the file to remove.

getHashCodeBasedOnObjectContent

private static String getHashCodeBasedOnObjectContent(Serializable object)

Calculates the hashcode for the serializable object based on its content.

Parameters:

object - serializable object.

Returns:

the hashcode for serializable object.

Throws:

IllegalStateException - when some unexpected happened.

serialize

private static void serialize(Serializable object,
                              OutputStream outputStream)
                       throws IOException

Serializes object to output stream.

Parameters:

object - object to be serialized

outputStream - serialization stream

Throws:

IOException - if an error occurs

putExternalResources

public void putExternalResources(Set<String> locations)

Puts external resources in cache. If at least one external resource changed, clears the cache.

Parameters:

locations - locations of external resources.

loadExternalResources

private static Set<PropertyCacheFile.ExternalResource> loadExternalResources(Set<String> resourceLocations)

Loads a set of PropertyCacheFile.ExternalResource based on their locations.

Parameters:

resourceLocations - locations of external configuration resources.

Returns:

a set of PropertyCacheFile.ExternalResource.

loadExternalResource

private static byte[] loadExternalResource(String location)
                                    throws IOException,
                                           CheckstyleException

Loads the content of external resource.

Parameters:

location - external resource location.

Returns:

array of bytes which represents the content of external resource in binary form.

Throws:

IOException - if error while loading occurs.

CheckstyleException - if error while loading occurs.

toByteArray

private static byte[] toByteArray(InputStream stream)
                           throws IOException

Reads all the contents of an input stream and returns it as a byte array.

Parameters:

stream - The input stream to read from.

Returns:

The resulting byte array of the stream.

Throws:

IOException - if there is an error reading the input stream.

areExternalResourcesChanged

private boolean areExternalResourcesChanged(Set<PropertyCacheFile.ExternalResource> resources)

Checks whether the contents of external configuration resources were changed.

Parameters:

resources - a set of PropertyCacheFile.ExternalResource.

Returns:

true if the contents of external configuration resources were changed.

isResourceChanged

private boolean isResourceChanged(PropertyCacheFile.ExternalResource resource)

Checks whether the resource is changed.

Parameters:

resource - resource to check.

Returns:

true if resource is changed.

fillCacheWithExternalResources

private void fillCacheWithExternalResources(Set<PropertyCacheFile.ExternalResource> externalResources)

Fills cache with a set of PropertyCacheFile.ExternalResource. If external resource from the set is already in cache, it will be skipped.

Parameters:

externalResources - a set of PropertyCacheFile.ExternalResource.

isResourceLocationInCache

private boolean isResourceLocationInCache(String location)

Checks whether resource location is in cache.

Parameters:

location - resource location.

Returns:

true if resource location is in cache.