1 /**
2 * Copyright (c) 2008-2011, http://www.snakeyaml.org
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.yaml.snakeyaml.scanner;
18
19 import org.yaml.snakeyaml.tokens.Token;
20
21 /**
22 * This interface represents an input stream of {@link Token Tokens}.
23 * <p>
24 * The parser and the scanner form together the 'Parse' step in the loading
25 * process (see chapter 3.1 of the <a href="http://yaml.org/spec/1.1/">YAML
26 * Specification</a>).
27 * </p>
28 *
29 * @see org.yaml.snakeyaml.tokens.Token
30 */
31 public interface Scanner {
32
33 /**
34 * Check if the next token is one of the given types.
35 *
36 * @param choices
37 * token IDs.
38 * @return <code>true</code> if the next token can be assigned to a variable
39 * of at least one of the given types. Returns <code>false</code> if
40 * no more tokens are available.
41 * @throws ScannerException
42 * Thrown in case of malformed input.
43 */
44 boolean checkToken(Token.ID... choices);
45
46 /**
47 * Return the next token, but do not delete it from the stream.
48 *
49 * @return The token that will be returned on the next call to
50 * {@link #getToken}
51 * @throws ScannerException
52 * Thrown in case of malformed input.
53 */
54 Token peekToken();
55
56 /**
57 * Returns the next token.
58 * <p>
59 * The token will be removed from the stream.
60 * </p>
61 *
62 * @throws ScannerException
63 * Thrown in case of malformed input.
64 */
65 Token getToken();
66 }