52 lines
1.5 KiB
Java
52 lines
1.5 KiB
Java
package ch.nuth.zhaw.exbox;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.regex.MatchResult;
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import java.util.regex.Matcher;
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import java.util.regex.Pattern;
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public class BracketServer implements CommandExecutor {
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private static Pattern bracketPattern = Pattern.compile("(/\\*|\\*/|[(){}\\[\\]<>])");
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private static Map<String, String> bracketPairs;
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public BracketServer() {
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super();
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bracketPairs = new HashMap<>() {
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{
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put("(", ")");
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put("[", "]");
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put("{", "}");
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put("<", ">");
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put("/*", "*/");
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}
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};
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}
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@Override
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public String execute(String command) throws Exception {
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return Boolean.toString(checkBrackets(command)) + "\n";
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}
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public boolean checkBrackets(String expression) {
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ListStack openBrackets = new ListStack();
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Matcher matcher = bracketPattern.matcher(expression);
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Iterable<MatchResult> results = () -> matcher.results().iterator();
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for (MatchResult result : results) {
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if (bracketPairs.keySet().contains(result.group())) {
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openBrackets.push(result.group());
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} else if (
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!openBrackets.isEmpty() &&
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result.group().equals(bracketPairs.get(openBrackets.peek()))) {
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openBrackets.pop();
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} else {
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return false;
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}
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}
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return openBrackets.isEmpty();
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}
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}
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