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With inspiration from other libraries
package io.virtdata.core;
import io.virtdata.api.DataMapper;
import io.virtdata.api.ValueType;
import io.virtdata.ast.VirtDataFlow;
import io.virtdata.parser.VirtDataDSL;
import io.virtdata.templates.BindPoint;
import org.apache.commons.lang3.ClassUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.*;
public class VirtData {
private final static Logger logger = LoggerFactory.getLogger(VirtData.class);
/**
* Create a bindings template from the pair-wise names and specifiers.
* Each even-numbered (starting with zero) argument is a binding name,
* and each odd-numbered (starting with one) argument is a binding spec.
*
* @param namesAndSpecs names and specs in "name", "spec", ... form
* @return A bindings template that can be used to resolve a bindings instance
*/
public static BindingsTemplate getTemplate(String... namesAndSpecs) {
if ((namesAndSpecs.length % 2) != 0) {
throw new RuntimeException(
"args must be in 'name','spec', pairs. " +
"This can't be true for " + namesAndSpecs.length + "elements.");
}
List bindPoints = new ArrayList<>();
for (int i = 0; i < namesAndSpecs.length; i += 2) {
bindPoints.add(new BindPoint(namesAndSpecs[i],namesAndSpecs[i+1]));
}
return getTemplate(bindPoints);
}
// /**
// * Create a bindings template from the provided map, ensuring that
// * the syntax of the bindings specs is parsable first.
// *
// * @param namedBindings The named bindings map
// * @return a bindings template
// */
// public static BindingsTemplate getTemplate(Map namedBindings) {
//
// for (String bindingSpec : namedBindings.values()) {
// VirtDataDSL.ParseResult parseResult = VirtDataDSL.parse(bindingSpec);
// if (parseResult.throwable != null) {
// throw new RuntimeException(parseResult.throwable);
// }
// }
// return new BindingsTemplate(namedBindings);
// }
/**
* Create a bindings template from a provided list of {@link BindPoint}s,
* ensuring that the syntax of the bindings specs is parsable first.
*
* @param bindPoints A list of {@link BindPoint}s
* @return A BindingsTemplate
*/
public static BindingsTemplate getTemplate(List bindPoints) {
for (BindPoint bindPoint : bindPoints) {
String bindspec = bindPoint.getBindspec();
VirtDataDSL.ParseResult parseResult = VirtDataDSL.parse(bindspec);
if (parseResult.throwable!=null) {
throw new RuntimeException(parseResult.throwable);
}
}
return new BindingsTemplate(bindPoints);
}
/**
* Instantiate an optional data mapping function if possible.
*
* @param flowSpec The VirtData specifier for the mapping function
* @param The parameterized return type of the function
* @return An optional function which will be empty if the function could not be resolved.
*/
public static Optional> getOptionalMapper(String flowSpec) {
flowSpec = CompatibilityFixups.fixup(flowSpec);
VirtDataDSL.ParseResult parseResult = VirtDataDSL.parse(flowSpec);
if (parseResult.throwable != null) {
throw new RuntimeException(parseResult.throwable);
}
VirtDataFlow flow = parseResult.flow;
VirtDataComposer composer = new VirtDataComposer();
Optional resolvedFunction = composer.resolveFunctionFlow(flow);
return resolvedFunction.map(ResolvedFunction::getFunctionObject).map(DataMapperFunctionMapper::map);
}
public static ResolverDiagnostics getMapperDiagnostics(String flowSpec) {
try {
flowSpec = CompatibilityFixups.fixup(flowSpec);
VirtDataDSL.ParseResult parseResult = VirtDataDSL.parse(flowSpec);
if (parseResult.throwable != null) {
throw new RuntimeException(parseResult.throwable);
}
VirtDataFlow flow = parseResult.flow;
VirtDataComposer composer = new VirtDataComposer();
ResolverDiagnostics resolverDiagnostics = composer.resolveDiagnosticFunctionFlow(flow);
return resolverDiagnostics;
} catch (Exception e) {
return new ResolverDiagnostics().error(e);
}
}
/**
* Instantiate an optional data mapping function if possible, with type awareness. This version
* of {@link #getOptionalMapper(String)} will use the additional type information in the clazz
* parameter to automatically parameterize the flow specifier.
*
* If the flow specifier does contain
* an output type qualifier already, then a check is made to ensure that the output type qualifier is
* assignable to the specified class in the clazz parameter. This ensures that type parameter awareness
* at compile time is honored and verified when this call is made.
*
* @param flowSpec The VirtData specifier for the mapping function
* @param The parameterized return type of the function.
* @param clazz The explicit class which must be of type T or assignable to type T
* @return An optional function which will be empty if the function could not be resolved.
*/
public static Optional> getOptionalMapper(String flowSpec, Class clazz) {
flowSpec = CompatibilityFixups.fixup(flowSpec);
VirtDataDSL.ParseResult parseResult = VirtDataDSL.parse(flowSpec);
if (parseResult.throwable != null) {
throw new RuntimeException(parseResult.throwable);
}
VirtDataFlow flow = parseResult.flow;
String outputType = flow.getLastExpression().getCall().getOutputType();
Class outputClass = ValueType.classOfType(outputType);
if (outputClass != null) {
if (!ClassUtils.isAssignable(outputClass,clazz,true)) {
throw new RuntimeException("The flow specifier '" + flowSpec + "' wants an output type of '" + outputType +"', but this" +
" type is not assignable to the explicit class '" + clazz.getCanonicalName() + "' that was enforced at the API level." +
" Either remove the output type qualifier at the last function in the flow spec, or change it to something that can" +
" reliably be cast to type '" + clazz.getCanonicalName() +"'");
}
} else {
logger.debug("Auto-assigning output type qualifier '->" + clazz.getCanonicalName() + "' to specifier '" + flowSpec + "'");
flow.getLastExpression().getCall().setOutputType(clazz.getCanonicalName());
}
VirtDataComposer composer = new VirtDataComposer();
Optional resolvedFunction = composer.resolveFunctionFlow(flow);
Optional> mapper = resolvedFunction.map(ResolvedFunction::getFunctionObject).map(DataMapperFunctionMapper::map);
if (mapper.isPresent()) {
T actualTestValue = mapper.get().get(1L);
if (!ClassUtils.isAssignable(actualTestValue.getClass(),clazz,true)) {
throw new RuntimeException("The flow specifier '" + flowSpec + "' successfully created a function, but the test value" +
"(" + String.valueOf(actualTestValue) + ") of type [" + actualTestValue.getClass() + "] produced by it was not " +
"assignable to the type '" + clazz.getCanonicalName() + "' which was explicitly set" +
" at the API level.");
}
}
return mapper;
}
public static T getFunction(String flowSpec, Class functionType) {
Optional optionalFunction = getOptionalFunction(flowSpec, functionType);
return optionalFunction.orElseThrow();
}
public static Optional getOptionalFunction(String flowSpec, Class functionType) {
flowSpec = CompatibilityFixups.fixup(flowSpec);
Class requiredInputType = FunctionTyper.getInputClass(functionType);
Class requiredOutputType = FunctionTyper.getResultClass(functionType);
FunctionalInterface annotation = functionType.getAnnotation(FunctionalInterface.class);
if (annotation==null) {
throw new RuntimeException("You can only use function types that are tagged as @FunctionInterface");
}
VirtDataDSL.ParseResult parseResult = VirtDataDSL.parse(flowSpec);
if (parseResult.throwable != null) {
throw new RuntimeException(parseResult.throwable);
}
VirtDataFlow flow = parseResult.flow;
String specifiedInputClassName = flow.getFirstExpression().getCall().getInputType();
Class specifiedInputClass = ValueType.classOfType(specifiedInputClassName);
if (specifiedInputClass!=null) {
if (!ClassUtils.isAssignable(specifiedInputClass,requiredInputType,true)) {
throw new RuntimeException("The flow specifier '" + flowSpec + "' wants an input type of '" + specifiedInputClassName +"', but this" +
" type is not assignable to the input class required by the functional type requested '" + functionType.getCanonicalName() + "'. (type "+requiredInputType.getCanonicalName()+")" +
" Either remove the input type qualifier at the first function in the flow spec, or change it to something that can" +
" reliably be cast to type '" + requiredInputType.getCanonicalName() +"'");
}
} else {
logger.debug("Auto-assigning input type qualifier '" + requiredInputType.getCanonicalName() + "->' to specifier '" + flowSpec + "'");
flow.getFirstExpression().getCall().setInputType(requiredInputType.getCanonicalName());
}
String specifiedOutputClassName = flow.getLastExpression().getCall().getOutputType();
Class specifiedOutputClass = ValueType.classOfType(specifiedOutputClassName);
if (specifiedOutputClass != null) {
if (!ClassUtils.isAssignable(specifiedOutputClass,requiredOutputType,true)) {
throw new RuntimeException("The flow specifier '" + flowSpec + "' wants an output type of '" + specifiedOutputClass +"', but this" +
" type is not assignable to the output class required by functional type '" + functionType.getCanonicalName() + "'. (type "+requiredOutputType.getCanonicalName()+")" +
" Either remove the output type qualifier at the last function in the flow spec, or change it to something that can" +
" reliably be cast to type '" + requiredOutputType.getCanonicalName() +"'");
}
} else {
logger.debug("Auto-assigning output type qualifier '->" + requiredOutputType.getCanonicalName() + "' to specifier '" + flowSpec + "'");
flow.getLastExpression().getCall().setOutputType(requiredOutputType.getCanonicalName());
}
VirtDataComposer composer = new VirtDataComposer();
Optional resolvedFunction = composer.resolveFunctionFlow(flow);
return resolvedFunction.map(ResolvedFunction::getFunctionObject).map(functionType::cast);
}
/**
* Instantiate a data mapping function, or throw an exception.
*
* @param flowSpec The VirtData specifier for the mapping function
* @param The parameterized return type of the function
* @return A data mapping function
* @throws RuntimeException if the function could not be resolved
*/
public static DataMapper getMapper(String flowSpec) {
Optional> optionalMapper = getOptionalMapper(flowSpec);
return optionalMapper.orElseThrow(() -> new RuntimeException("Unable to find mapper: " + flowSpec));
}
/**
* Instantiate a data mapping function of the specified type, or throw an error.
*
* @param flowSpec The VirtData flow specifier for the function to be returned
* @param clazz The class of the data mapping function return type
* @param The parameterized class of the data mapping return type
* @return A new data mapping function.
* @throws RuntimeException if the function could not be resolved
*/
public static DataMapper getMapper(String flowSpec, Class clazz) {
Optional> dataMapper = getOptionalMapper(flowSpec, clazz);
DataMapper mapper = dataMapper.orElseThrow(() -> new RuntimeException("Unable to find mapper: " + flowSpec));
return mapper;
}
}