Examples with NDimensionalArray org.apache.apex.malhar.python.base.util.NDimensionalArray used on opensource projects

Example 1 with NDimensionalArray

use of org.apache.apex.malhar.python.base.util.NDimensionalArray in project apex-malhar by apache.

the class InterpreterThread method eval.

/**
 * Evaluates a string expression by passing in any variable subsitution into the Interpreter space if required. Also
 * handles the garbage collection of the variables passed and offers a configurable way to delete any variable created
 *  as part of the evaluation expression.
 * @param command The string equivalent of the command
 * @param variableToExtract The name of the variable that would need to be extracted from the python interpreter space
 *                          to the JVM space.
 * @param variableSubstituionParams Key value pairs representing the variables that need to be passed into the
 *                                  interpreter space and are part of the eval expression.
 * @param deleteExtractedVariable if the L.H.S. of an assignment expression variable needs to be deleted. This is
 *                                essentially the variable that is being requested to extract i.e. the second
 *                                parameter to this method.
 * @param expectedReturnType Class representing the expected return type
 * @param <T> Template signature for the expected return type
 * @return The value that is extracted from the interpreter space ( possibly created as part of the eval expression or
 *  otherwise ). Returns null if any error
 */
private <T> T eval(String command, String variableToExtract, Map<String, Object> variableSubstituionParams, boolean deleteExtractedVariable, Class<T> expectedReturnType) {
    T variableToReturn = null;
    LOG.debug("Executing eval expression " + command + " with return type : " + expectedReturnType);
    try {
        for (String aKey : variableSubstituionParams.keySet()) {
            Object keyVal = variableSubstituionParams.get(aKey);
            if (keyVal instanceof NDimensionalArray) {
                keyVal = ((NDimensionalArray) keyVal).toNDArray();
            }
            JEP_INSTANCE.set(aKey, keyVal);
        }
    } catch (JepException e) {
        errorEncountered = true;
        LOG.error("Error while setting the params for eval expression " + command, e);
        return null;
    }
    try {
        LOG.debug("Executing the eval expression in the interpreter instance " + command);
        JEP_INSTANCE.eval(command);
    } catch (JepException e) {
        errorEncountered = true;
        LOG.error("Error while evaluating the expression " + command, e);
        return null;
    }
    try {
        if (variableToExtract != null) {
            Object extractedVariable = JEP_INSTANCE.getValue(variableToExtract);
            if (extractedVariable instanceof NDArray) {
                LOG.debug(" Return type is a NumPy Array. Hence converting to NDimensionalArray instance");
                NDArray ndArrayJepVal = (NDArray) extractedVariable;
                NDimensionalArray nDimArray = new NDimensionalArray();
                nDimArray.setData(ndArrayJepVal.getData());
                nDimArray.setSignedFlag(ndArrayJepVal.isUnsigned());
                int[] dimensions = ndArrayJepVal.getDimensions();
                nDimArray.setDimensions(dimensions);
                int lengthInOneDimension = 1;
                for (int i = 0; i < dimensions.length; i++) {
                    lengthInOneDimension *= dimensions[i];
                }
                nDimArray.setLengthOfSequentialArray(lengthInOneDimension);
                variableToReturn = expectedReturnType.cast(nDimArray);
            } else {
                variableToReturn = expectedReturnType.cast(extractedVariable);
            }
            if (deleteExtractedVariable) {
                LOG.debug("Deleting the extracted variable from the Python interpreter space");
                JEP_INSTANCE.eval(PYTHON_DEL_COMMAND + variableToExtract);
            }
        }
        LOG.debug("Deleting all the variables from the python interpreter space ");
        for (String aKey : variableSubstituionParams.keySet()) {
            LOG.debug("Deleting " + aKey);
            JEP_INSTANCE.eval(PYTHON_DEL_COMMAND + aKey);
        }
    } catch (JepException e) {
        errorEncountered = true;
        LOG.error("Error while evaluating delete part of expression " + command, e);
        return null;
    }
    return variableToReturn;
}