From f93806753eccf6a8c89471be04a499154ef318b3 Mon Sep 17 00:00:00 2001
From: Paolo Arcaini <parcaini@gmail.com>
Date: Wed, 29 May 2019 09:08:57 +0900
Subject: [PATCH] oracle

---
 mutrex/src/regex/oracle/AutomaticOracle.java | 26 ++++++++
 mutrex/src/regex/oracle/CachedOracle.java    | 69 ++++++++++++++++++++
 mutrex/src/regex/oracle/RegexOracle.java     | 11 ++++
 mutrex/src/regex/oracle/RgxAcception.java    |  5 ++
 mutrex/src/regex/oracle/UserOracle.java      | 26 ++++++++
 5 files changed, 137 insertions(+)
 create mode 100644 mutrex/src/regex/oracle/AutomaticOracle.java
 create mode 100644 mutrex/src/regex/oracle/CachedOracle.java
 create mode 100644 mutrex/src/regex/oracle/RegexOracle.java
 create mode 100644 mutrex/src/regex/oracle/RgxAcception.java
 create mode 100644 mutrex/src/regex/oracle/UserOracle.java

diff --git a/mutrex/src/regex/oracle/AutomaticOracle.java b/mutrex/src/regex/oracle/AutomaticOracle.java
new file mode 100644
index 0000000..7cc39de
--- /dev/null
+++ b/mutrex/src/regex/oracle/AutomaticOracle.java
@@ -0,0 +1,26 @@
+package regex.oracle;
+
+import dk.brics.automaton.Automaton;
+import dk.brics.automaton.RegExp;
+import dk.brics.automaton.RunAutomaton;
+
+/** it represents an oracle given by a regex */
+public class AutomaticOracle implements RegexOracle {
+	private Automaton automaton;
+	private RunAutomaton automatonRunner;
+
+	public AutomaticOracle(String regex) {
+		this(new RegExp(regex));
+	}
+
+	public AutomaticOracle(RegExp regExp) {
+		assert regExp != null;
+		automaton = regExp.toAutomaton();
+		automatonRunner = new RunAutomaton(automaton);
+	}
+
+	@Override
+	public boolean accept(String s) {
+		return automatonRunner.run(s);
+	}
+}
diff --git a/mutrex/src/regex/oracle/CachedOracle.java b/mutrex/src/regex/oracle/CachedOracle.java
new file mode 100644
index 0000000..0af9cb3
--- /dev/null
+++ b/mutrex/src/regex/oracle/CachedOracle.java
@@ -0,0 +1,69 @@
+package regex.oracle;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * it is an oracle that keeps memory of the string it has been asked
+ * 
+ * @author garganti
+ *
+ */
+public class CachedOracle implements RegexOracle {
+	private Set<String> acceptedByOracle;
+	private Set<String> rejectedByOracle;
+	private RegexOracle oracle;
+
+	// the real oracle to ask in case there is new string to evaluate
+	public CachedOracle(RegexOracle oracle) {
+		acceptedByOracle = new HashSet<String>();
+		rejectedByOracle = new HashSet<String>();
+		this.oracle = oracle;
+	}
+
+	/**
+	 * it keeps track also of the string previously evaluated to reduce the number
+	 * of evaluations
+	 * 
+	 * @param s
+	 * @return
+	 */
+	@Override
+	public final boolean accept(String s) {
+		// if already evaluated
+		if (acceptedByOracle.contains(s)) {
+			return true;
+		} else if (rejectedByOracle.contains(s)) {
+			return false;
+		} else {
+			// not evaluated yet
+			boolean isAccepted = oracle.accept(s);
+			if (isAccepted) {
+				acceptedByOracle.add(s);
+			} else {
+				rejectedByOracle.add(s);
+			}
+			return isAccepted;
+		}
+	}
+
+	public Set<String> getAcceptedByOracle() {
+		return acceptedByOracle;
+	}
+
+	public Set<String> getRejectedByOracle() {
+		return rejectedByOracle;
+	}
+
+	public int getNumEvaluatedStrings() {
+		return acceptedByOracle.size() + rejectedByOracle.size();
+	}
+
+	public int getNumAcceptedStrings() {
+		return acceptedByOracle.size();
+	}
+
+	public RegexOracle getOracle() {
+		return oracle;
+	}
+}
diff --git a/mutrex/src/regex/oracle/RegexOracle.java b/mutrex/src/regex/oracle/RegexOracle.java
new file mode 100644
index 0000000..60848c1
--- /dev/null
+++ b/mutrex/src/regex/oracle/RegexOracle.java
@@ -0,0 +1,11 @@
+package regex.oracle;
+
+// given an example, it is able to accept or reject
+// the cached version is in another class
+// this one has no memory
+public interface RegexOracle {
+
+	/** is string s accepted by the oracle */
+	public abstract boolean accept(String s);
+
+}
diff --git a/mutrex/src/regex/oracle/RgxAcception.java b/mutrex/src/regex/oracle/RgxAcception.java
new file mode 100644
index 0000000..f2b10ef
--- /dev/null
+++ b/mutrex/src/regex/oracle/RgxAcception.java
@@ -0,0 +1,5 @@
+package regex.oracle;
+
+public enum RgxAcception {
+	FULLY_ACCEPTED, FULLY_REJECTED, PARTIALLY_ACCEPTED
+}
\ No newline at end of file
diff --git a/mutrex/src/regex/oracle/UserOracle.java b/mutrex/src/regex/oracle/UserOracle.java
new file mode 100644
index 0000000..9bf7cec
--- /dev/null
+++ b/mutrex/src/regex/oracle/UserOracle.java
@@ -0,0 +1,26 @@
+package regex.oracle;
+
+import java.util.Scanner;
+
+public class UserOracle implements RegexOracle {
+
+	@Override
+	public boolean accept(String s) {
+		return askUser(s, "accept");
+	}
+
+	private boolean askUser(String s, String acceptReject) {
+		Scanner in = new Scanner(System.in);
+		while (true) {
+			System.out.println("Do you " + acceptReject + " \"" + s + "\"?" + " Y for yes, N for no");
+			String line = in.nextLine();
+			if (line.equalsIgnoreCase("Y")) {
+				return true;
+			}
+			if (line.equalsIgnoreCase("N")) {
+				return false;
+			}
+			System.out.println("I did not understand.");
+		}
+	}
+}
\ No newline at end of file