com.blazebit.persistence.impl.function.stringjsonagg.GroupConcatBasedStringJsonAggFunction Maven / Gradle / Ivy

/*
 * Copyright 2014 - 2020 Blazebit.
 *
 * 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.blazebit.persistence.impl.function.stringjsonagg;

import com.blazebit.persistence.impl.function.Order;
import com.blazebit.persistence.impl.function.chr.ChrFunction;
import com.blazebit.persistence.impl.function.concat.ConcatFunction;
import com.blazebit.persistence.impl.function.groupconcat.AbstractGroupConcatFunction;
import com.blazebit.persistence.impl.function.replace.ReplaceFunction;
import com.blazebit.persistence.spi.FunctionRenderContext;

import java.util.Collections;

/**
 * @author Christian Beikov
 * @since 1.5.0
 */
public class GroupConcatBasedStringJsonAggFunction extends AbstractStringJsonAggFunction {

    private final AbstractGroupConcatFunction groupConcatFunction;
    private final ConcatFunction concatFunction;
    private final String start;
    private final String end;

    public GroupConcatBasedStringJsonAggFunction(AbstractGroupConcatFunction groupConcatFunction, ChrFunction chrFunction, ReplaceFunction replaceFunction, ConcatFunction concatFunction) {
        this.groupConcatFunction = groupConcatFunction;
        this.concatFunction = concatFunction;
        String backslash = chrFunction.getEncodedString(Integer.toString('\\'));
        String backslashB = chrFunction.getEncodedString(Integer.toString('\b'));
        String backslashF = chrFunction.getEncodedString(Integer.toString('\f'));
        String backslashN = chrFunction.getEncodedString(Integer.toString('\n'));
        String backslashR = chrFunction.getEncodedString(Integer.toString('\r'));
        String backslashT = chrFunction.getEncodedString(Integer.toString('\t'));
        String backslashBackslash = concatFunction.startConcat() + backslash + concatFunction.concatSeparator() + backslash + concatFunction.endConcat();
        String backslashBackslashB = concatFunction.startConcat() + backslash + concatFunction.concatSeparator() + chrFunction.getEncodedString(Integer.toString('\b')) + concatFunction.endConcat();
        String backslashBackslashF = concatFunction.startConcat() + backslash + concatFunction.concatSeparator() + chrFunction.getEncodedString(Integer.toString('\f')) + concatFunction.endConcat();
        String backslashBackslashN = concatFunction.startConcat() + backslash + concatFunction.concatSeparator() + chrFunction.getEncodedString(Integer.toString('\n')) + concatFunction.endConcat();
        String backslashBackslashR = concatFunction.startConcat() + backslash + concatFunction.concatSeparator() + chrFunction.getEncodedString(Integer.toString('\r')) + concatFunction.endConcat();
        String backslashBackslashT = concatFunction.startConcat() + backslash + concatFunction.concatSeparator() + chrFunction.getEncodedString(Integer.toString('\t')) + concatFunction.endConcat();
        String backslashSlash = concatFunction.startConcat() + backslash + concatFunction.concatSeparator() + chrFunction.getEncodedString(Integer.toString('/')) + concatFunction.endConcat();
        String backslashQuote = concatFunction.startConcat() + backslash + concatFunction.concatSeparator() + "'\"'" + concatFunction.endConcat();

        String argument = "\0";
        argument = replaceFunction.getReplaceString(argument, backslash, backslashBackslash);
        argument = replaceFunction.getReplaceString(argument, "'/'", backslashSlash);
        argument = replaceFunction.getReplaceString(argument, backslashB, backslashBackslashB);
        argument = replaceFunction.getReplaceString(argument, backslashF, backslashBackslashF);
        argument = replaceFunction.getReplaceString(argument, backslashN, backslashBackslashN);
        argument = replaceFunction.getReplaceString(argument, backslashR, backslashBackslashR);
        argument = replaceFunction.getReplaceString(argument, backslashT, backslashBackslashT);
        argument = replaceFunction.getReplaceString(argument, "'\"'", backslashQuote);
        String[] split = argument.split("\0");
        this.start = split[0];
        this.end = split[1];
    }

    @Override
    public void render(FunctionRenderContext context) {
        if ((context.getArgumentsSize() & 1) == 1) {
            throw new RuntimeException("The string_json_agg function needs an even amount of arguments , , ..., , ! args=" + context);
        }
        context.addChunk(concatFunction.startConcat());
        context.addChunk("'['");
        context.addChunk(concatFunction.concatSeparator());

        StringBuilder sb = new StringBuilder();
        render(sb, context);

        groupConcatFunction.render(context, new AbstractGroupConcatFunction.GroupConcat(false, sb.toString(), Collections.emptyList(), ","));

        context.addChunk(concatFunction.concatSeparator());
        context.addChunk("']'");
        context.addChunk(concatFunction.endConcat());
    }

    protected void render(StringBuilder sb, FunctionRenderContext context) {
        sb.append(concatFunction.startConcat());
        sb.append("'{\"'");
        sb.append(concatFunction.concatSeparator());
        sb.append(context.getArgument(0));
        for (int i = 1; i < context.getArgumentsSize(); i++) {
            if ((i & 1) == 1) {
                sb.append(concatFunction.concatSeparator());
                sb.append("'\":'");
                sb.append(concatFunction.concatSeparator());
                sb.append(coalesceStart());
                sb.append(concatFunction.startConcat());
                sb.append("'\"'");
                sb.append(concatFunction.concatSeparator());
                sb.append(start);
                sb.append(context.getArgument(i));
                sb.append(end);
                sb.append(concatFunction.concatSeparator());
                sb.append("'\"'");
                sb.append(concatFunction.endConcat());
                sb.append(coalesceEnd());
            } else {
                sb.append(concatFunction.concatSeparator());
                sb.append("','");
                sb.append(concatFunction.concatSeparator());
                sb.append("'\"'");
                sb.append(concatFunction.concatSeparator());
                sb.append(context.getArgument(i));
            }
        }
        sb.append(concatFunction.concatSeparator());
        sb.append("'}'");
        sb.append(concatFunction.endConcat());
    }

    protected String coalesceStart() {
        return "coalesce(";
    }

    protected String coalesceEnd() {
        return ",'null')";
    }

}