/*************************GO-LICENSE-START*********************************
* Copyright 2014 ThoughtWorks, Inc.
*
* 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.
*************************GO-LICENSE-END***********************************/
package com.thoughtworks.go.config.preprocessor;
public class ParamStateMachine {
public ParamStateMachine() {
}
public String process(String preResolved, ParamHandler paramsHandler) {
ReaderState state = ReaderState.NOT_IN_PATTERN;
for (int i = 0; i < preResolved.length(); i++) {
state = state.interpret(preResolved.charAt(i), paramsHandler);
}
paramsHandler.handleAfterResolution(state);
return paramsHandler.getResult();
}
public enum ReaderState {
IN_PATTERN {
ReaderState interpret(char ch, ParamHandler paramsHandler) {
if (ch == CHAR_CURL_CLOSE) {
try {
paramsHandler.handlePatternFound(pattern);
} finally {
pattern.setLength(0);
}
return NOT_IN_PATTERN;
} else {
pattern.append(ch);
return IN_PATTERN;
}
}
},
NOT_IN_PATTERN {
ReaderState interpret(char ch, ParamHandler paramsHandler) {
if (ch == CHAR_HASH) {
return HASH_SEEN;
}
paramsHandler.handleNotInPattern(ch);
return NOT_IN_PATTERN;
}
},
HASH_SEEN {
ReaderState interpret(char ch, ParamHandler paramsHandler) {
if (ch == CHAR_HASH) {
paramsHandler.handlePatternStarted(ch);
return NOT_IN_PATTERN;
} else if (ch == CHAR_CURL_OPEN) {
return IN_PATTERN;
}
return INVALID_PATTERN;
}
},
INVALID_PATTERN {
ReaderState interpret(char ch, ParamHandler paramsHandler) {
return INVALID_PATTERN;
}
};
private static final char CHAR_CURL_CLOSE = '}';
private static final char CHAR_CURL_OPEN = '{';
private static final char CHAR_HASH = '#';
protected StringBuilder pattern = new StringBuilder();
abstract ReaderState interpret(char ch, ParamHandler paramsHandler);
}
}