pro.verron.officestamper.core.StandardMethodResolver Maven / Gradle / Ivy

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Office-stamper is a Java template engine for docx documents, forked from org.wickedsource.docx-stamper
There is a newer version: 2.6.0
package pro.verron.officestamper.core;

import org.springframework.core.convert.TypeDescriptor;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.MethodExecutor;
import org.springframework.expression.MethodResolver;
import org.springframework.expression.TypedValue;
import org.springframework.lang.NonNull;

import java.lang.reflect.Method;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.function.Function;

/**
 * Resolves methods that are used as expression functions or comment processors.
 *
 * @author Joseph Verron
 * @version ${version}
 * @since 1.6.2
 */
public class StandardMethodResolver implements MethodResolver {
	private final Map, Object> commentProcessors;
	private final Map, Object> expressionFunctions;
	private final Function onFail;

	/**
	 * Constructor for StandardMethodResolver.
	 *
	 * @param commentProcessors   map of comment processors
	 * @param expressionFunctions map of expression functions
	 * @param onResolutionFail    function that is called when a method cannot be resolved
	 */
	public StandardMethodResolver(
			Map, Object> commentProcessors,
			Map, Object> expressionFunctions,
			Function onResolutionFail
	) {
		this.commentProcessors = commentProcessors;
		this.expressionFunctions = expressionFunctions;
		this.onFail = onResolutionFail;
	}

	/** {@inheritDoc} */
	@Override
	public MethodExecutor resolve(
			@NonNull EvaluationContext context,
			@NonNull Object targetObject,
			@NonNull String name,
			@NonNull List argumentTypes
	) {
		return findCommentProcessorMethod(name, argumentTypes)
				.or(() -> findExpressionContextMethod(name, argumentTypes))
				.map(invoker -> new StandardMethodExecutor(invoker, onFail))
				.orElse(null);
	}

	private Optional findCommentProcessorMethod(String expectedName, List expectedArguments) {
		return findMethodInMap(commentProcessors, expectedName, expectedArguments);
	}

	private Optional findExpressionContextMethod(String expectedName, List expectedArguments) {
		return findMethodInMap(expressionFunctions, expectedName, expectedArguments);
	}

	private Optional findMethodInMap(Map, Object> methodMap, String expectedName, List expectedArguments) {
		for (Map.Entry, Object> entry : methodMap.entrySet()) {
			Class iface = entry.getKey();
			for (Method actualMethod : iface.getDeclaredMethods())
				if (methodEquals(actualMethod, expectedName, expectedArguments))
					return Optional.of(args -> actualMethod.invoke(entry.getValue(), args));
		}
		return Optional.empty();
	}

	private boolean methodEquals(Method actualMethod, String expectedName, List expectedArguments) {
		if (!actualMethod.getName().equals(expectedName)) return false;
		if (actualMethod.getParameterTypes().length != expectedArguments.size()) return false;

		for (int i = 0; i < expectedArguments.size(); i++) {
			Class expectedType = expectedArguments.get(i) != null ? expectedArguments.get(i).getType() : null;
			Class actualType = actualMethod.getParameterTypes()[i];
			// null is allowed in place of any argument type
			if (expectedType != null && !actualType.isAssignableFrom(expectedType)) {
				return false;
			}
		}
		return true;
	}
}