CharacterReader Class — spring-boot Architecture

Source Code

core/spring-boot/src/main/java/org/springframework/boot/env/OriginTrackedPropertiesLoader.java lines 195–328

	private static class CharacterReader implements Closeable {

		private static final String[] ESCAPES = { "trnf", "\t\r\n\f" };

		private final LineNumberReader reader;

		private int columnNumber = -1;

		private boolean escaped;

		private int character;

		private int lastLineCommentPrefixCharacter;

		CharacterReader(Resource resource, @Nullable Charset encoding) throws IOException {
			this.reader = new LineNumberReader(new InputStreamReader(resource.getInputStream(),
					(encoding != null) ? encoding : StandardCharsets.ISO_8859_1));
		}

		@Override
		public void close() throws IOException {
			this.reader.close();
		}

		boolean read() throws IOException {
			this.escaped = false;
			this.character = this.reader.read();
			this.columnNumber++;
			if (this.columnNumber == 0) {
				skipWhitespace();
			}
			if (this.character == '\\') {
				this.escaped = true;
				readEscaped();
			}
			else if (this.character == '\n') {
				this.columnNumber = -1;
			}
			return !isEndOfFile();
		}

		private void skipWhitespace() throws IOException {
			while (isWhiteSpace()) {
				this.character = this.reader.read();
				this.columnNumber++;
			}
		}

		private void setLastLineCommentPrefixCharacter(int lastLineCommentPrefixCharacter) {
			this.lastLineCommentPrefixCharacter = lastLineCommentPrefixCharacter;
		}

		private void skipComment() throws IOException {
			while (this.character != '\n' && this.character != -1) {
				this.character = this.reader.read();
			}
			this.columnNumber = -1;
		}

		private void readEscaped() throws IOException {
			this.character = this.reader.read();
			int escapeIndex = ESCAPES[0].indexOf(this.character);
			if (escapeIndex != -1) {
				this.character = ESCAPES[1].charAt(escapeIndex);
			}
			else if (this.character == '\n') {
				this.columnNumber = -1;
				read();
			}
			else if (this.character == 'u') {
				readUnicode();
			}
		}

		private void readUnicode() throws IOException {
			this.character = 0;
			for (int i = 0; i < 4; i++) {
				int digit = this.reader.read();
				if (digit >= '0' && digit <= '9') {
					this.character = (this.character << 4) + digit - '0';
				}
				else if (digit >= 'a' && digit <= 'f') {
					this.character = (this.character << 4) + digit - 'a' + 10;
				}
				else if (digit >= 'A' && digit <= 'F') {
					this.character = (this.character << 4) + digit - 'A' + 10;
				}
				else {
					throw new IllegalStateException("Malformed \\uxxxx encoding.");
				}
			}
		}

		boolean isWhiteSpace() {
			return !this.escaped && (this.character == ' ' || this.character == '\t' || this.character == '\f');
		}

		boolean isEndOfFile() {
			return this.character == -1;
		}

		boolean isEndOfLine() {
			return this.character == -1 || (!this.escaped && this.character == '\n');
		}

		boolean isListDelimiter() {
			return !this.escaped && this.character == ',';
		}

		boolean isPropertyDelimiter() {
			return !this.escaped && (this.character == '=' || this.character == ':');
		}

		char getCharacter() {
			return (char) this.character;
		}

		Location getLocation() {
			return new Location(this.reader.getLineNumber(), this.columnNumber);
		}

		boolean isSameLastLineCommentPrefix() {
			return this.lastLineCommentPrefixCharacter == this.character;
		}

		boolean isCommentPrefixCharacter() {
			return this.character == '#' || this.character == '!';
		}

		boolean isHyphenCharacter() {
			return this.character == '-';
		}

	}