Examples with IMutationDataSource org.apache.asterix.metadata.declared.IMutationDataSource used on opensource projects

Example 1 with IMutationDataSource

use of org.apache.asterix.metadata.declared.IMutationDataSource in project asterixdb by apache.

the class MetaKeyExpressionReferenceTransform method visit.

private ILogicalExpressionReferenceTransformWithCondition visit(Mutable<ILogicalOperator> opRef) throws AlgebricksException {
    ILogicalOperator op = opRef.getValue();
    // Reaches NTS or ETS.
    if (op.getInputs().size() == 0) {
        return NoOpExpressionReferenceTransform.INSTANCE;
    }
    // Datascan returns an useful transform if the meta part presents in the dataset.
    if (op.getOperatorTag() == LogicalOperatorTag.DATASOURCESCAN) {
        DataSourceScanOperator scanOp = (DataSourceScanOperator) op;
        ILogicalExpressionReferenceTransformWithCondition inputTransfomer = visit(op.getInputs().get(0));
        DataSource dataSource = (DataSource) scanOp.getDataSource();
        List<ILogicalExpressionReferenceTransformWithCondition> transformers = null;
        List<LogicalVariable> allVars = scanOp.getVariables();
        LogicalVariable dataVar = dataSource.getDataRecordVariable(allVars);
        LogicalVariable metaVar = dataSource.getMetaVariable(allVars);
        LogicalExpressionReferenceTransform currentTransformer = null;
        // https://issues.apache.org/jira/browse/ASTERIXDB-1618
        if (dataSource.getDatasourceType() != DataSource.Type.EXTERNAL_DATASET && dataSource.getDatasourceType() != DataSource.Type.INTERNAL_DATASET && dataSource.getDatasourceType() != DataSource.Type.LOADABLE) {
            IMutationDataSource mds = (IMutationDataSource) dataSource;
            if (mds.isChange()) {
                transformers = new ArrayList<>();
                transformers.add(new MetaKeyExpressionReferenceTransform(mds.getPkVars(allVars), mds.getKeyAccessExpression()));
            } else if (metaVar != null) {
                transformers = new ArrayList<>();
                transformers.add(new MetaKeyToFieldAccessTransform(metaVar));
            }
        }
        if (!dataSource.hasMeta() && transformers == null) {
            return inputTransfomer;
        }
        if (metaVar != null) {
            currentTransformer = new LogicalExpressionReferenceTransform(dataVar, metaVar);
        }
        if (inputTransfomer.equals(NoOpExpressionReferenceTransform.INSTANCE) && transformers == null) {
            return currentTransformer;
        } else if (inputTransfomer.equals(NoOpExpressionReferenceTransform.INSTANCE) && currentTransformer == null) {
            return transformers.get(0);
        } else {
            // Requires an argument variable to resolve ambiguity.
            if (transformers == null) {
                transformers = new ArrayList<>();
            }
            if (!inputTransfomer.equals(NoOpExpressionReferenceTransform.INSTANCE)) {
                inputTransfomer.setVariableRequired();
                transformers.add(inputTransfomer);
            }
            currentTransformer.setVariableRequired();
            transformers.add(currentTransformer);
            return new CompositeExpressionReferenceTransform(transformers);
        }
    }
    // Visits children in the depth-first order.
    List<ILogicalExpressionReferenceTransformWithCondition> transformers = new ArrayList<>();
    for (Mutable<ILogicalOperator> childRef : op.getInputs()) {
        ILogicalExpressionReferenceTransformWithCondition transformer = visit(childRef);
        if (!transformer.equals(NoOpExpressionReferenceTransform.INSTANCE)) {
            transformers.add(transformer);
        }
    }
    ILogicalExpressionReferenceTransformWithCondition currentTransformer = null;
    if (transformers.size() == 0) {
        currentTransformer = NoOpExpressionReferenceTransform.INSTANCE;
    } else if (transformers.size() == 1) {
        currentTransformer = transformers.get(0);
    } else {
        // Transformers in a CompositeTransformer should require argument variable check.
        for (ILogicalExpressionReferenceTransformWithCondition transformer : transformers) {
            transformer.setVariableRequired();
        }
        currentTransformer = new CompositeExpressionReferenceTransform(transformers);
    }
    rewritten |= op.acceptExpressionTransform(currentTransformer);
    return currentTransformer;
}