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Port of jsonata.js to Java to enable rules for JSON content
/**
* (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.regex.Matcher;
import java.util.regex.Pattern;
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.ExprContext;
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/string-functions.html:
*
* $match(str, pattern [, limit])
*
* Finds occurrences of pattern within str and reports them with their index and
* group.
*
* If str is not specified, then the context value is used as the value of str.
* It is an error if str is not a string.
*
* The pattern parameter must be a regular expression (regex) String used for
* searching the string.
*
* The optional limit parameter, is a number that specifies the maximum number
* of results to be found before stopping.
*
* Examples
*
* $match("John Smith and John Jones", "John") ==
* "[{"match":"John","index":0,"groups":["John"]},{"match":"John","index":15,"groups":["John"]}]
*
*/
public class MatchFunction extends FunctionBase implements Function {
public static String ERR_BAD_CONTEXT = String.format(Constants.ERR_MSG_BAD_CONTEXT, Constants.FUNCTION_MATCH);
public static String ERR_ARG1BADTYPE = String.format(Constants.ERR_MSG_ARG1_BAD_TYPE, Constants.FUNCTION_MATCH);
public static String ERR_ARG2BADTYPE = String.format(Constants.ERR_MSG_ARG2_BAD_TYPE, Constants.FUNCTION_MATCH);
public static String ERR_ARG3BADTYPE = String.format(Constants.ERR_MSG_ARG3_BAD_TYPE, Constants.FUNCTION_MATCH);
public static String ERR_ARG4BADTYPE = String.format(Constants.ERR_MSG_ARG4_BAD_TYPE, Constants.FUNCTION_MATCH);
public JsonNode invoke(ExpressionsVisitor expressionVisitor, Function_callContext ctx) {
// Create the variable to return
SelectorArrayNode result = null;
// Retrieve the number of arguments
JsonNode argString = JsonNodeFactory.instance.nullNode();
boolean useContext = FunctionUtils.useContextVariable(this, ctx, getSignature());
int argCount = getArgumentCount(ctx);
if (useContext) {
argString = FunctionUtils.getContextVariable(expressionVisitor);
if (argString != null && argString.isNull() == false) {
argCount++;
} else {
useContext = false;
}
}
// Make sure that we have the right number of arguments
if (argCount == 2 || argCount == 3) {
if (!useContext) {
argString = FunctionUtils.getValuesListExpression(expressionVisitor, ctx, 0);
}
if (argString == null) {
return null;
}
if (!argString.isTextual()) {
throw new EvaluateRuntimeException(ERR_ARG1BADTYPE);
}
final JsonNode argPattern = FunctionUtils.getValuesListExpression(expressionVisitor, ctx,
useContext ? 0 : 1);
int limit = -1;
// Make sure that we have the right number of arguments
if (argString == null || !argString.isTextual() || argString.asText().isEmpty()) {
throw new EvaluateRuntimeException(ERR_ARG1BADTYPE);
}
// Make sure that the pattern is a non-empty string
if (argPattern != null && argPattern.isTextual() && !(argPattern.asText().isEmpty())) {
// Check to see if the separator is just a string
final String str = argString.textValue();
final String pattern = argPattern.textValue();
if (argCount == 3) {
final JsonNode argLimit = FunctionUtils.getValuesListExpression(expressionVisitor, ctx,
useContext ? 1 : 2);
// Check to see if we have an optional limit argument we check it
if (argLimit != null) {
if (argLimit.isNumber() && argLimit.asInt() >= 0) {
limit = argLimit.asInt();
} else {
throw new EvaluateRuntimeException(ERR_ARG3BADTYPE);
}
}
}
final Pattern regexPattern = Pattern.compile(pattern);
final Matcher matcher = regexPattern.matcher(str);
// Check to see if a limit was specified
result = new SelectorArrayNode(JsonNodeFactory.instance);
if (limit == -1) {
// No limits... match all occurrences in the string
while (matcher.find()) {
ObjectNode obj = JsonNodeFactory.instance.objectNode();
obj.put("match", str.substring(matcher.start(), matcher.end()));
obj.put("start", new Long(matcher.start()));
ArrayNode groups = JsonNodeFactory.instance.arrayNode();
obj.set("groups", groups);
groups.add(matcher.group());
result.add(obj);
}
} else if (limit > 0) {
int count = 0;
while (matcher.find() && count < limit) {
count++;
ObjectNode obj = JsonNodeFactory.instance.objectNode();
obj.put("match", str.substring(matcher.start(), matcher.end()));
obj.put("start", new Long(matcher.start()));
ArrayNode groups = JsonNodeFactory.instance.arrayNode();
obj.set("groups", groups);
groups.add(matcher.group());
result.add(obj);
}
} else {
return null;
}
} else {
// check for a function call context as 2nd parameter
ExprContext exprCtx = ctx.exprValues().exprList().expr(useContext ? 0 : 1);
if (exprCtx instanceof Function_callContext) {
// try for declared then jsonata
Function_callContext fctCallCtx= (Function_callContext)exprCtx;
String fctName = fctCallCtx.VAR_ID().getText();
DeclaredFunction declFct = expressionVisitor.getDeclaredFunction(fctName);
if (declFct == null) {
Function function = expressionVisitor.getJsonataFunction(fctName);
if (function != null) {
result = (SelectorArrayNode) function.invoke(expressionVisitor, fctCallCtx);
} else {
throw new EvaluateRuntimeException("Unknown function: " + fctName);
}
} else {
result = (SelectorArrayNode) declFct.invoke(expressionVisitor, fctCallCtx);
}
} else {
/*
* TODO: Add support for regex patterns using / delimiters once the grammar has
* been updated. For now, simply throw an exception.
*/
throw new EvaluateRuntimeException(ERR_ARG2BADTYPE);
}
}
} else {
throw new EvaluateRuntimeException(argCount <= 1 ? ERR_ARG1BADTYPE : ERR_ARG4BADTYPE);
}
return result;
}
@Override
public int getMaxArgs() {
return 3;
}
@Override
public int getMinArgs() {
return 1; // account for context variable
}
@Override
public String getSignature() {
// accepts a string (or context variable), a function (that accepts a string and
// returns an object), an optional number, returns an array of objects
return "n?:a>";
}
}