MockLexerAdapterWithLookaheadLLStar.java

package com.sap.furcas.runtime.parser.incremental;

import java.util.Collections;
import java.util.List;

import org.antlr.runtime.Lexer;

import com.sap.furcas.metamodel.FURCAS.textblocks.AbstractToken;
import com.sap.ide.cts.parser.incremental.IncrementalLexer;
import com.sap.ide.cts.parser.incremental.antlr.ANTLRIncrementalLexerAdapter;
import com.sap.ide.cts.parser.incremental.antlr.ANTLRLexerAdapter;

public class MockLexerAdapterWithLookaheadLLStar extends ANTLRLexerAdapter {

    public MockLexerAdapterWithLookaheadLLStar(Lexer antlrLexer) {
        super(antlrLexer, null);
    }

    protected List<AbstractToken> nextTokens;
    protected ANTLRIncrementalLexerAdapter callbackLexer;
    protected int nextTokenIndex = 0;

    @Override
    public List<AbstractToken> moreTokens() {
        // simulate a lookahead of 1 within a LL(*) parser
        int mark = callbackLexer.mark();
        callbackLexer.LA(1);
        callbackLexer.consume();
        callbackLexer.rewind(mark);
        // simulate token consumption on callbacked lexer
        callbackLexer.consume();
        return Collections.singletonList(nextTokens.get(nextTokenIndex++));
    }

    @Override
    public void setIncrementalLexer(IncrementalLexer incrementalLexer) {
        this.callbackLexer = (ANTLRIncrementalLexerAdapter) incrementalLexer;
    }

    public void setNextTokens(List<AbstractToken> nextTokens) {
        this.nextTokens = nextTokens;
    }

}