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/*
* Copyright 2016 the original author or authors.
*
* 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.github.drinkjava2.jdialects;
/**
* Dialect function Utils, detail see render method
*
* @author Yong Zhu
* @since 1.0.2
*/
public class DialectFunctionUtils {// NOSONAR
/**
* The render method translate function template to real SQL piece
*
*
* Template can be:
* "*": standard SQL function, identical to abc($Params)
* "abc($Params)": template with special parameter format:
"$P1, $P2, $P3, $P4, $P5, $P6..."="$Params"
"$P1,$P2,$P3,$P4,$P5,$P6..."="$Compact_Params"
"$P1||$P2||$P3||$P4||$P5||$P6..."="$Lined_Params"
"$P1+$P2+$P3+$P4+$P5+$P6..."="$Add_Params");
"$P1 in $P2 in $P3 in $P4 in $P5 in $P6..."="$IN_Params"
"$P1%pattern$P2%pattern$P3%pattern$P4%pattern$P5%pattern$P6..."="$Pattern_Params"
"11%startswith$P2%startswith$P3%startswith$P4%startswith$P5%startswith$P6..."= "$Startswith_Params");
"nvl($P1, nvl($P2, nvl($P3, nvl($P4, nvl($P5, $P6...)))))"="$NVL_Params");
*
* "0=abc()": function do not support parameter
* "1=abc($P1)": function only support 1 parameter
* "2=abc($P1,$P2)": function only support 2 parameters
* "0=abc()|1=abc($P1)|3=abc($P1,$P2,$P3)": function support 0 or 1 or 3 parameters
*
*
*
* @param functionName function name
* @param args function parameters
* @return A SQL function piece
*/
protected static String render(Dialect d, String functionName, String... args) {
String template = d.functions.get(functionName.toLowerCase());
DialectException.assureNotEmpty(template, "Dialect \"" + d + "\" does not support \"" + functionName
+ "\" function, a full list of supported functions of this dialect can see \"DatabaseDialects.xls\"");
if ("*".equals(template))
template = functionName + "($Params)";
char c = template.charAt(1);
if (c != '=') {
if (template.indexOf("$Params") >= 0) {
return StrUtils.replace(template, "$Params", StrUtils.arrayToString(args, ", "));
}
if (template.indexOf("$Compact_Params") >= 0) {
return StrUtils.replace(template, "$Compact_Params", StrUtils.arrayToString(args, ","));
}
if (template.indexOf("$Lined_Params") >= 0) {
return StrUtils.replace(template, "$Lined_Params", StrUtils.arrayToString(args, "||"));
}
if (template.indexOf("$Add_Params") >= 0) {
return StrUtils.replace(template, "$Add_Params", StrUtils.arrayToString(args, "+"));
}
if (template.indexOf("$IN_Params") >= 0) {
return StrUtils.replace(template, "$IN_Params", StrUtils.arrayToString(args, " in "));
}
if (template.indexOf("$Pattern_Params") >= 0) {
return StrUtils.replace(template, "$Pattern_Params", StrUtils.arrayToString(args, "%pattern"));
}
if (template.indexOf("$Startswith_Params") >= 0) {
return StrUtils.replace(template, "$Startswith_Params", StrUtils.arrayToString(args, "%startswith"));
}
if (template.indexOf("$NVL_Params") >= 0) {
if (args == null || args.length < 2)
DialectException.throwEX("Nvl function require at least 2 parameters");
else {
String s = "nvl(" + args[args.length - 2] + ", " + args[args.length - 1] + ")";
for (int i = args.length - 3; i > -1; i--)
s = "nvl(" + args[i] + ", " + s + ")";
return StrUtils.replace(template, "$NVL_Params", s);
}
}
return (String) DialectException.throwEX("jDialect found a template bug error, please submit this bug");
} else {
int argsCount = 0;
if (args != null)
argsCount = args.length;
String searchStr = Integer.toString(argsCount) + "=";
if (template.indexOf(searchStr) < 0)
DialectException.throwEX("Dialect " + d + "'s function \"" + functionName + "\" only support "
+ allowedParameterQTY(template) + " parameters");
String result = StrUtils.substringBetween(template + "|", searchStr, "|");
for (int i = 0; args != null && i < args.length; i++) {
result = StrUtils.replace(result, "$P" + (i + 1), "" + args[i]);
}
return result;
}
}
private static String allowedParameterQTY(String template) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < 5; i++) {
if (template.indexOf(Integer.toString(i) + "=") >= 0)
sb.append(Integer.toString(i)).append(" or ");
}
if (sb.length() > 0)
sb.setLength(sb.length() - 4);
return sb.toString();
}
}