antlr-3.4/tool/src/test/java/org/antlr/test/TestBufferedTreeNodeStream.java

/*
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 *  Copyright (c) 2010 Terence Parr
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package org.antlr.test;

import org.antlr.runtime.CommonToken;
import org.antlr.runtime.tree.BufferedTreeNodeStream;
import org.antlr.runtime.tree.CommonTree;
import org.antlr.runtime.tree.Tree;
import org.antlr.runtime.tree.TreeNodeStream;
import org.junit.Test;

public class TestBufferedTreeNodeStream extends TestTreeNodeStream {
    // inherits tests; these methods make it use a new buffer

	public TreeNodeStream newStream(Object t) {
		return new BufferedTreeNodeStream(t);
	}

    public String toTokenTypeString(TreeNodeStream stream) {
        return ((BufferedTreeNodeStream)stream).toTokenTypeString();
    }

    @Test public void testSeek() throws Exception {
        // ^(101 ^(102 103 ^(106 107) ) 104 105)
        // stream has 7 real + 6 nav nodes
        // Sequence of types: 101 DN 102 DN 103 106 DN 107 UP UP 104 105 UP EOF
        Tree r0 = new CommonTree(new CommonToken(101));
        Tree r1 = new CommonTree(new CommonToken(102));
        r0.addChild(r1);
        r1.addChild(new CommonTree(new CommonToken(103)));
        Tree r2 = new CommonTree(new CommonToken(106));
        r2.addChild(new CommonTree(new CommonToken(107)));
        r1.addChild(r2);
        r0.addChild(new CommonTree(new CommonToken(104)));
        r0.addChild(new CommonTree(new CommonToken(105)));

        TreeNodeStream stream = newStream(r0);
        stream.consume(); // consume 101
        stream.consume(); // consume DN
        stream.consume(); // consume 102
        stream.seek(7);   // seek to 107
        assertEquals(107, ((Tree)stream.LT(1)).getType());
        stream.consume(); // consume 107
        stream.consume(); // consume UP
        stream.consume(); // consume UP
        assertEquals(104, ((Tree)stream.LT(1)).getType());
    }    
}