192

Performance Considerations

buffer = new byte[MAX_CACHE_ENTRY_SIZE];

}

public InputSource resolveEntity(String publicId,

String systemId) throws IOException, SAXException {

InputStream stream = getEntity(publicId, systemId);

if (stream != null) {

InputSource source = new InputSource(stream);

source.setPublicId(publicId);

source.setSystemId(systemId);

return source;

}

return null;

}

private InputStream getEntity(String publicId, String systemId)

throws IOException, SAXException {

Entity entity = null;

SoftReference reference

= (SoftReference) entities.get(systemId);

if (reference != null) {

// Got a soft reference to the entity, 

// let's get the actual entity.

entity = (Entity) reference.get();

}

if (entity == null) {

// The entity has been reclaimed by the GC or was 

// never created, let's download it again! Delegate to 

// the parent resolver that implements the actual 

// resolution strategy.

InputSource source

= parentResolver.resolveEntity(publicId, systemId);

if (source != null) {

return cacheEntity(publicId, systemId,

source.getByteStream());

}

return null;

}

return new ByteArrayInputStream(entity.content);