Package org.openehealth.ipf.commons.xml

Class AbstractCachingXmlProcessor<T>

java.lang.Object

org.openehealth.ipf.commons.xml.AbstractCachingXmlProcessor<T>

Type Parameters:

T - resource type.

Direct Known Subclasses:

XqjTransmogrifier, XsdValidator, XsltTransmogrifier

public abstract class AbstractCachingXmlProcessor<T>
extends Object

Abstract parent class for XML validators, transmogrifiers, and other classes which cache static external resources in memory.
On the basis of validator/transmogrifier parameters (Object... params), instances of this class determine:

• Location of the raw resource (i.e. an unparsed XSLT document as opposed to its compiled representation in memory) — method resourceLocation(Object...),
• Parameters of resource instantiation (compilation) and execution (application) — method resourceParameters(Object...),
• Key to store the compiled resource in the cache — method resourceCacheKey(Object...).

The main method to get a ready-to-use resource instance is resource(Object...), which takes over instantiation, initialization, caching, and other aspects of resource lifecycle. For resource instantiation step, it calls the createResource(Object...) method, which is truly resource-type specific and thus declared as abstract in the given base class.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	AbstractCachingXmlProcessor.Loader<S>

Field Summary

Fields

Modifier and Type	Field	Description
static final String	RESOURCE_LOCATION

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractCachingXmlProcessor(ClassLoader classLoader)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected abstract T	createResource(Object... params)	Creates a ready-to-use resource (e.g. an XML Schema instance) for the given key.
protected abstract ConcurrentMap<String,AbstractCachingXmlProcessor.Loader<T>>	getCache()
protected T	resource(Object... params)	Retrieves from the cache and returns the resource with the given location and further attributes.
protected String	resourceCacheKey(Object... params)	Extracts (constructs) resource cache key validator/transmogrifier parameters.
protected StreamSource	resourceContent(Object... params)	Loads the resource into memory and returns it as a Stream.
protected String	resourceLocation(Object... params)	Extracts (constructs) resource location from validator/transmogrifier parameters.
protected Map<String,Object>	resourceParameters(Object... params)	Extracts (constructs) resource creation/application parameters from validator/transmogrifier parameters.

Methods inherited from class java.lang.Object

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

Field Details

RESOURCE_LOCATION

public static final String RESOURCE_LOCATION

See Also:

• Constant Field Values

Constructor Details

AbstractCachingXmlProcessor

protected AbstractCachingXmlProcessor(ClassLoader classLoader)

Constructor.

Parameters:

classLoader - class loader, may be null.

Method Details

getCache

protected abstract ConcurrentMap<String,AbstractCachingXmlProcessor.Loader<T>> getCache()

Returns:

static cache for the configured resource type. Note that the returned Map is not necessarily synchronized.

resourceLocation

protected String resourceLocation(Object... params)

Extracts (constructs) resource location from validator/transmogrifier parameters.

Parameters:

params - validator/transmogrifier parameters.

Returns:

resource location as a String.

resourceCacheKey

protected String resourceCacheKey(Object... params)

Extracts (constructs) resource cache key validator/transmogrifier parameters.

Per default, the key equals to the resource location.

Parameters:

params - validator/transmogrifier parameters.

Returns:

cache key as a String.

resourceParameters

protected Map<String,Object> resourceParameters(Object... params)

Extracts (constructs) resource creation/application parameters from validator/transmogrifier parameters.

Parameters:

params - validator/transmogrifier parameters.

Returns:

resource creation/application parameters as a Map, or null if not found.

resource

protected T resource(Object... params)
              throws Exception

Retrieves from the cache and returns the resource with the given location and further attributes. If necessary, creates the resource by means of createResource(Object...) and stores it into the cache. The cache key is a combination of the location and further attributes.

This method MUST be re-entrant, its result MUST be thread-safe.

Parameters:

params - validator/transmogrifier parameters.

Returns:

resource instance.

Throws:

Exception - exception

createResource

protected abstract T createResource(Object... params)

Creates a ready-to-use resource (e.g. an XML Schema instance) for the given key. Insertion into the cache will happen externally, this method's purpose is only to instantiate the resource to be cached.

This method does not need to be re-entrant, but its result MUST be thread-safe.

Parameters:

params - validator/transmogrifier parameters.

Returns:

resource of the configured type.

resourceContent

protected StreamSource resourceContent(Object... params)

Loads the resource into memory and returns it as a Stream.

This method does not need to be re-entrant.

Parameters:

params - validator/transmogrifier parameters.

Returns:

resource of the configured type.