String manipulation additions

More and better ways to manipulate strings

1 files changed, 112 insertions, 0 deletions

diff --git a/BJC-Utils2/src/main/java/bjc/utils/funcutils/NeoTokenSplitter.java b/BJC-Utils2/src/main/java/bjc/utils/funcutils/NeoTokenSplitter.java
new file mode 100644
index 0000000..fd4b130
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/funcutils/NeoTokenSplitter.java
@@ -0,0 +1,112 @@
+package bjc.utils.funcutils;
+
+import java.util.regex.Pattern;
+
+/**
+ * Split a string and keep given delimiters.
+ *
+ * @author Ben Culkin
+ */
+public class NeoTokenSplitter {
+	/*
+	 * This string is a format template for the delimiter matching regex
+	 *
+	 * It does two things
+	 * 1. Match the provided delimiter by positive lookahead
+	 * 2. Match the provided delimiter by positive lookbehind
+	 *
+	 * Thus, it will only match in places where the delimiter is, but won't
+	 * actually match the delimiter, leaving split to put it into the stream
+	 */
+	private static String WITH_DELIM = "((?<=%1$s)|(?=%1$s))";
+
+	/*
+	 * This string is a format template for the multi-delimiter matching
+	 * regex.
+	 *
+	 * It does the same thing as the single delimiter regex, but has to have
+	 * some negative lookahead/lookbehind assertions to avoid splitting a
+	 * delimiter into pieces.
+	 */
+	private static String WITH_MULTI_DELIM = "((?<=%1$s+)(?!%1$s)|(?<!%1$s)(?=%1$s+))";
+
+	private StringBuilder currPatt;
+
+	private Pattern compPatt;
+
+	/**
+	 * Create a new token splitter.
+	 */
+	public NeoTokenSplitter() {
+	}
+
+	/**
+	 * Split a provided string using configured delimiters, and keeping the
+	 * delimiters.
+	 *
+	 * The splitter must be compiled first.
+	 *
+	 * @param inp The string to split.
+	 *
+	 * @return The split string, including delimiters.
+	 *
+	 * @throws IllegalStateException If the splitter isn't compiled.
+	 */
+	public String[] split(String inp) {
+		if(compPatt == null) {
+			throw new IllegalStateException("Token splitter has not been compiled yet");
+		}
+
+		return compPatt.split(inp);
+	}
+
+	/**
+	 * Adds a string as a matched delimiter to split on.
+	 *
+	 * Only works for fixed length delimiters.
+	 *
+	 * The provided string is regex-escaped before being used.
+	 *
+	 * @param delim The delimiter to match on.
+	 */
+	public void addDelimiter(String delim) {
+		String delimPat = String.format(WITH_DELIM, Pattern.quote(delim));
+
+		if(currPatt == null) {
+			currPatt = new StringBuilder();
+
+			currPatt.append("(?:" + delimPat + ")");
+		} else {
+			currPatt.append("|(?:" + delimPat + ")");
+		}
+	}
+
+	/**
+	 * Adds a character class as a matched delimiter to split on.
+	 *
+	 * The provided string should be a pattern to match one or more
+	 * occurances of.
+	 *
+	 * @param delim The delimiter to split on.
+	 */
+	public void addMultiDelimiter(String delim) {
+		String delimPat = String.format(WITH_MULTI_DELIM, "(?:" + delim + ")");
+
+		if(currPatt == null) {
+			currPatt = new StringBuilder();
+
+			currPatt.append("(?:" + delimPat + ")");
+		} else {
+			currPatt.append("|(?:" + delimPat + ")");
+		}
+	}
+
+	/**
+	 * Compiles the current set of delimiters to a pattern.
+	 *
+	 * Makes this splitter ready to use.
+	 */
+	public void compile() {
+		compPatt = Pattern.compile(currPatt.toString());
+	}
+}