foam.lib.parse.ErrorReportingPStream.java Source code

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Here is the source code for foam.lib.parse.ErrorReportingPStream.java

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/**
 * @license
 * Copyright 2017 The FOAM Authors. All Rights Reserved.
 * http://www.apache.org/licenses/LICENSE-2.0
 */

package foam.lib.parse;

import org.apache.commons.lang3.StringUtils;

import java.util.HashSet;
import java.util.Set;

public class ErrorReportingPStream extends ProxyPStream {

    protected Parser errParser = null;
    protected ParserContext errContext = null;
    protected ErrorReportingNodePStream errStream = null;

    protected ErrorReportingNodePStream tail_ = null;
    protected Set<String> validCharacters = new HashSet<>();

    public ErrorReportingPStream(PStream delegate) {
        setDelegate(delegate);
    }

    @Override
    public PStream tail() {
        // tail becomes new node with increased position
        if (tail_ == null)
            tail_ = new ErrorReportingNodePStream(this, super.tail(), 1);
        return tail_;
    }

    @Override
    public PStream setValue(Object value) {
        // create a new node
        return new ErrorReportingNodePStream(this, super.setValue(value), 0);
    }

    @Override
    public PStream apply(Parser parser, ParserContext x) {
        PStream result = parser.parse(this, x);
        if (result == null) {
            // if result is null then self report
            this.report(new ErrorReportingNodePStream(this, getDelegate(), 0), parser, x);
        }
        return result;
    }

    public void report(ErrorReportingNodePStream ernps, Parser parser, ParserContext x) {
        // get the report with the furthest position
        if (errStream == null || errStream.pos_ <= ernps.pos_) {
            errStream = ernps;
            errParser = parser;
            errContext = x;
        }
    }

    public void reportValidCharacter(Character ch) {
        validCharacters.add("'" + getPrintableCharacter(ch) + "'");
    }

    public String getMessage() {
        // check if err is valid and print the char, if not print EOF
        String invalid = (errStream.valid()) ? String.valueOf(errStream.head()) : "EOF";

        // get a list of valid characters
        TrapPStream trap = new TrapPStream(this);
        for (int i = 0; i <= 255; i++) {
            trap.setHead((char) i);
            trap.apply(errParser, errContext);
        }

        return "Invalid character '" + invalid + "' found at " + errStream.pos_ + "\n"
                + "Valid characters include: " + StringUtils.join(validCharacters, ",");
    }

    public String getPrintableCharacter(Character ch) {
        switch ((int) ch) {
        case 0x09:
            return "\\t";
        case 0x0A:
            return "\\n";
        case 0x0D:
            return "\\r";
        default:
            return ch.toString();
        }
    }
}