Java View.beginIndex doesn't support multiple view indexing

[pasin]

Can we make the interface below support multiple view indexing?

cbforest/Java/jni/native_view.cc

Lines 124 to 134 in d0afb82

	JNIEXPORT jlong JNICALL Java_com_couchbase_cbforest_View_beginIndex
	(JNIEnv *env, jobject self, jlong dbHandle, jlong viewHandle)
	{
	C4View* view = (C4View*)viewHandle;
	C4Error error;
	C4Indexer* indexer = c4indexer_begin((C4Database*)dbHandle, &view, 1, &error);
	if (!indexer)
	throwError(env, error);
	return (jlong)indexer;
	}

[hideki]

This blocks to fix https://github.com/couchbase/couchbase-lite-java-core/issues/681

[snej]

The intent is that you can create multiple c4Indexers at the same time, and then iterate through the docs once, feeding each indexer its keys and values.

Looking at the API, what's missing is a version of c4indexer_enumerateDocuments that takes multiple indexers as input, computes the earliest sequence that needs to be indexed, and starts from there. Should be easy to do.

[pasin]

@snej I think the enumerateDocuments logic that you described above has already been implemented as C4Indexer extended from MapReduceIndexer. The only missing piece is that multiple views if available should be given to c4indexer_begin() instead of only just 1 from the current view (See beginIndex code). Probably we also need to extract an Indexer class from the View class in order to do that.

[snej]

Just uploaded PR #48 to support this.