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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 com.api.jsonata4java.expressions.EvaluateRuntimeException;
import com.api.jsonata4java.expressions.ExpressionsVisitor;
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.JsonNodeFactory;
import com.fasterxml.jackson.databind.node.TextNode;
/**
* From http://docs.jsonata.org/string-functions.html:
*
* $trim(str)
*
* Normalizes and trims all whitespace characters in str by applying the
* following steps:
*
* * All tabs, carriage returns, and line feeds are replaced with spaces. *
* Contiguous sequences of spaces are reduced to a single space. * Trailing and
* leading spaces are removed.
*
* If str is not specified (i.e. this function is invoked with no arguments),
* then the context value is used as the value of str. An error is thrown if str
* is not a string.
*
* Examples
*
* $trim(" Hello \n World ")=="Hello World"
*
*/
public class TrimFunction extends FunctionBase implements Function {
public static String ERR_BAD_CONTEXT = String.format(Constants.ERR_MSG_BAD_CONTEXT, Constants.FUNCTION_TRIM);
public static String ERR_ARG1BADTYPE = String.format(Constants.ERR_MSG_ARG1_BAD_TYPE, Constants.FUNCTION_TRIM);
public static String ERR_ARG2BADTYPE = String.format(Constants.ERR_MSG_ARG2_BAD_TYPE, Constants.FUNCTION_TRIM);
public JsonNode invoke(ExpressionsVisitor expressionVisitor, Function_callContext ctx) {
// Create the variable to return
JsonNode 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 == 1) {
if (!useContext) {
argString = FunctionUtils.getValuesListExpression(expressionVisitor, ctx, 0);
}
if (argString != null) {
if (argString.isTextual()) {
final String str = argString.textValue();
result = new TextNode(str.trim().replaceAll("\\s+", " "));
}
}
} else {
if (argCount != 0) {
throw new EvaluateRuntimeException(argCount == 0 ? ERR_BAD_CONTEXT : ERR_ARG2BADTYPE);
} // else returns null
}
return result;
}
@Override
public int getMaxArgs() {
return 1;
}
@Override
public int getMinArgs() {
return 0; // account for context
}
@Override
public String getSignature() {
// accepts a string (or context variable), returns a string
return "";
}
}