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/*
* Copyright 2014 Atteo.
*
* 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.
*/
package org.atteo.dollarbrace.spi;
import java.util.ArrayList;
import java.util.List;
public class Tokenizer {
public static final class Token {
private final String value;
private final boolean property;
public Token(String value, boolean property) {
this.value = value;
this.property = property;
}
public String getValue() {
return value;
}
public boolean isProperty() {
return property;
}
}
/**
* Splits given string into {@link Token tokens}.
*
* Token is ordinary text or property placeholder: ${name}.
* For instance the string: "abc${abc}abc" will be split
* into three tokens: text "abc", property "abc" and text "abc".
*
* @param input input string to split into tokens
* @return list of tokens
*/
public static List splitIntoTokens(String input) {
List parts = new ArrayList<>();
int index = 0;
while (true) {
int startPosition = input.indexOf("${", index);
if (startPosition == -1) {
break;
}
// find '${' and '}' pair, correctly handle nested pairs
boolean lastDollar = false;
int count = 1;
int countBrace = 0;
int endposition;
for (endposition = startPosition + 2; endposition < input.length(); endposition++) {
if (input.charAt(endposition) == '$') {
lastDollar = true;
continue;
}
if (input.charAt(endposition) == '{') {
if (lastDollar) {
count++;
} else {
countBrace++;
}
} else if (input.charAt(endposition) == '}') {
if (countBrace > 0) {
countBrace--;
} else {
count--;
if (count == 0) {
break;
}
}
}
lastDollar = false;
}
if (count > 0) {
break;
}
if (index != startPosition) {
parts.add(new Token(input.substring(index, startPosition), false));
}
String propertyName = input.substring(startPosition + 2, endposition);
index = endposition + 1;
parts.add(new Token(propertyName, true));
}
if (index != input.length()) {
parts.add(new Token(input.substring(index), false));
}
return parts;
}
}