com.api.jsonata4java.expressions.functions.KeysFunction Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of JSONata4Java Show documentation
Port of jsonata.js to Java to enable rules for JSON content
There is a newer version: 2.5.1
/**
 * (c) Copyright 2018, 2019 IBM Corporation
 * 1 New Orchard Road, 
 * Armonk, New York, 10504-1722
 * United States
 * +1 914 499 1900
 * support: Nathaniel Mills [email protected]
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package com.api.jsonata4java.expressions.functions;

import java.util.Iterator;

import com.api.jsonata4java.expressions.EvaluateRuntimeException;
import com.api.jsonata4java.expressions.ExpressionsVisitor;
import com.api.jsonata4java.expressions.ExpressionsVisitor.SelectorArrayNode;
import com.api.jsonata4java.expressions.generated.MappingExpressionParser.Function_callContext;
import com.api.jsonata4java.expressions.utils.Constants;
import com.api.jsonata4java.expressions.utils.FunctionUtils;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.JsonNodeFactory;
import com.fasterxml.jackson.databind.node.ObjectNode;

/**
 * From http://docs.jsonata.org/object-functions.html
 * 
 * $keys(object)
 * 
 * Returns the keys in an array of Strings. It is an error if the input is not
 * an object.
 * 
 * Example
 * 
 * $keys({"a":1,"b":2})==["a", "b"]
 * 
 */
public class KeysFunction extends FunctionBase implements Function {

	public static String ERR_BAD_CONTEXT = String.format(Constants.ERR_MSG_BAD_CONTEXT, Constants.FUNCTION_KEYS);
	public static String ERR_ARG1BADTYPE = String.format(Constants.ERR_MSG_ARG1_BAD_TYPE, Constants.FUNCTION_KEYS);
	public static String ERR_ARG2BADTYPE = String.format(Constants.ERR_MSG_ARG2_BAD_TYPE, Constants.FUNCTION_KEYS);

	public JsonNode invoke(ExpressionsVisitor expressionVisitor, Function_callContext ctx) {
		// Create the variable to return
		ObjectNode result = new ObjectNode(JsonNodeFactory.instance);

		// Retrieve the number of arguments
		JsonNode argObject = JsonNodeFactory.instance.nullNode();
		boolean useContext = FunctionUtils.useContextVariable(this, ctx, getSignature());
		int argCount = getArgumentCount(ctx);
		if (useContext) {
			argObject = FunctionUtils.getContextVariable(expressionVisitor);
			if (argObject != null && argObject.isNull() == false) {
				argCount++;
			} else {
				useContext = false;
			}
		}

		// Make sure that we have the right number of arguments
		if (argCount == 1) {
			if (!useContext) {
				argObject = FunctionUtils.getValuesListExpression(expressionVisitor, ctx, 0);
			}
			if (argObject == null) {
				return null;
			}
			// Check the type of the argument
			String key = "";
			if (argObject.isObject()) {
				ObjectNode obj = (ObjectNode) argObject;
				for (Iterator it = obj.fieldNames(); it.hasNext();) {
					key = it.next();
					if (result.get(key) == null) {
						result.put(key,true);
					}
				}
			} else {
				if (argObject.isArray()) {
					findObjects((ArrayNode)argObject,result);
				} else {
					/*
					 * The input argument is not an array. Throw a suitable exception
					 */
					return null;
					// throw new EvaluateRuntimeException(ERR_ARG1BADTYPE);
				}
			}
		} else {
			throw new EvaluateRuntimeException(argCount == 0 ? ERR_BAD_CONTEXT : ERR_ARG2BADTYPE);
		}
		if (result.size() == 0) {
			return null;
		}
		SelectorArrayNode output = new SelectorArrayNode(JsonNodeFactory.instance);
		for (Iteratorit = result.fieldNames(); it.hasNext(); ) {
			output.add(it.next());
		}
		return ExpressionsVisitor.unwrapArray(output);
	}
	
	static void findObjects(ArrayNode array,ObjectNode result) {
		for (int i=0;i it = obj.fieldNames(); it.hasNext();) {
			key = it.next();
			if (result.get(key) == null) {
				result.put(key,true);
			}
//			value = obj.get(key);
//			if (value != null) {
//				if (value.isArray()) {
//					ArrayNode subArray = JsonNodeFactory.instance.arrayNode();
//					findObjects((ArrayNode)value,subArray);
//					if (subArray.size() > 0) {
//						result.add(subArray);
//					}
//				} else if (value.isObject()) {
//					// not implemented in jsonata.js
//				}
//			}
		}
	}

	@Override
	public int getMaxArgs() {
		return 1;
	}
	@Override
	public int getMinArgs() {
		return 0; // account for context variable
	}

	@Override
	public String getSignature() {
		// accepts an object (or context variable), returns an array of strings
		return ">";
	}
}