PropertyFileContent Class — spring-boot Architecture

Source Code

core/spring-boot/src/main/java/org/springframework/boot/env/ConfigTreePropertySource.java lines 265–378

	private static final class PropertyFileContent implements Value, OriginProvider {

		private final Path path;

		private final Lock resourceLock = new ReentrantLock();

		private final Resource resource;

		private final Origin origin;

		private final boolean cacheContent;

		private final boolean autoTrimTrailingNewLine;

		private volatile byte @Nullable [] content;

		private PropertyFileContent(Path path, Resource resource, Origin origin, boolean cacheContent,
				boolean autoTrimTrailingNewLine) {
			this.path = path;
			this.resource = resource;
			this.origin = origin;
			this.cacheContent = cacheContent;
			this.autoTrimTrailingNewLine = autoTrimTrailingNewLine;
		}

		@Override
		public Origin getOrigin() {
			return this.origin;
		}

		@Override
		public int length() {
			return toString().length();
		}

		@Override
		public char charAt(int index) {
			return toString().charAt(index);
		}

		@Override
		public CharSequence subSequence(int start, int end) {
			return toString().subSequence(start, end);
		}

		@Override
		public String toString() {
			String string = new String(getBytes());
			if (this.autoTrimTrailingNewLine) {
				string = autoTrimTrailingNewLine(string);
			}
			return string;
		}

		private String autoTrimTrailingNewLine(String string) {
			if (!string.endsWith("\n")) {
				return string;
			}
			int numberOfLines = 0;
			for (int i = 0; i < string.length(); i++) {
				char ch = string.charAt(i);
				if (ch == '\n') {
					numberOfLines++;
				}
			}
			if (numberOfLines > 1) {
				return string;
			}
			return (string.endsWith("\r\n")) ? string.substring(0, string.length() - 2)
					: string.substring(0, string.length() - 1);
		}

		@Override
		public InputStream getInputStream() throws IOException {
			if (!this.cacheContent) {
				assertStillExists();
				return this.resource.getInputStream();
			}
			return new ByteArrayInputStream(getBytes());
		}

		private byte[] getBytes() {
			try {
				if (!this.cacheContent) {
					assertStillExists();
					return FileCopyUtils.copyToByteArray(this.resource.getInputStream());
				}
				byte[] content = this.content;
				if (content == null) {
					assertStillExists();
					this.resourceLock.lock();
					try {
						content = this.content;
						if (content == null) {
							content = FileCopyUtils.copyToByteArray(this.resource.getInputStream());
							this.content = content;
						}
					}
					finally {
						this.resourceLock.unlock();
					}
				}
				return content;
			}
			catch (IOException ex) {
				throw new IllegalStateException(ex);
			}
		}

		private void assertStillExists() {
			Assert.state(Files.exists(this.path), () -> "The property file '" + this.path + "' no longer exists");
		}

	}