finite automata example (#1364)

2017-03-12 18:15:29 +02:00
parent 818eeeeb18
commit 19ff2eb487
7 changed files with 254 additions and 0 deletions
@@ -0,0 +1,82 @@
+package algorithms;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+import com.baeldung.automata.*;
+
+/**
+ * Tests for {@link RtFiniteStateMachine}
+ */
+public final class RtFiniteStateMachineTest {
+
+	@Test
+    public void acceptsSimplePair() {
+    	String json = "{\"key\":\"value\"}";
+    	FiniteStateMachine machine = this.buildJsonStateMachine();
+    	for (int i=0;i<json.length();i++) {
+    	    machine = machine.switchState(String.valueOf(json.charAt(i)));
+    	}
+    	assertTrue(machine.canStop());
+    }
+	@Test
+    public void acceptsMorePairs() {
+    	String json = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
+    	FiniteStateMachine machine = this.buildJsonStateMachine();
+    	for (int i=0;i<json.length();i++) {
+    	    machine = machine.switchState(String.valueOf(json.charAt(i)));
+    	}
+    	assertTrue(machine.canStop());
+    }
+	
+	@Test(expected = IllegalArgumentException.class)
+    public void missingColon() {
+    	String json = "{\"key\"\"value\"}";
+    	FiniteStateMachine machine = this.buildJsonStateMachine();
+    	for (int i=0;i<json.length();i++) {
+    	    machine = machine.switchState(String.valueOf(json.charAt(i)));
+    	}
+    }
+
+	/**
+	 * Builds a finite state machine to validate a simple
+	 * Json object.
+	 * @return
+	 */
+	private FiniteStateMachine buildJsonStateMachine() {
+		State first = new RtState();
+    	State second = new RtState();
+    	State third = new RtState();
+    	State fourth = new RtState();
+    	State fifth = new RtState();
+    	State sixth = new RtState();
+    	State seventh = new RtState();
+    	State eighth = new RtState(true);
+
+    	first.with(new RtTransition("{", second));
+    	second.with(new RtTransition("\"", third));
+    	//Add transitions with chars 0-9 and a-z
+    	for (int i = 0; i < 26; i++) {
+    		if(i<10) {
+        	    third = third.with(
+            	    new RtTransition(String.valueOf(i), third)
+            	);
+        	    sixth = sixth.with(
+                	new RtTransition(String.valueOf(i), sixth)
+                );
+    		}
+    	    third = third.with(
+    	        new RtTransition(String.valueOf((char) ('a' + i)), third)
+    	    );
+    	    sixth = sixth.with(
+        	    new RtTransition(String.valueOf((char) ('a' + i)), sixth)
+        	);
+    	}
+    	third.with(new RtTransition("\"", fourth));
+    	fourth.with(new RtTransition(":", fifth));
+    	fifth.with(new RtTransition("\"", sixth));
+    	sixth.with(new RtTransition("\"", seventh));
+    	seventh.with(new RtTransition(",", second));
+    	seventh.with(new RtTransition("}", eighth));
+    	return new RtFiniteStateMachine(first);
+	}
+}