Optimize the code in TimeBounds. (#270)

* fix: parameters checking rule in TimeBounds.

* feat: add `TimeBounds.afterNow` and tests for `TimeBounds`

* style: Optimize code style in `TimeBounds`.

* rename `TimeBounds.afterNow` to `TimeBounds.expiresAfter`.

src/main/java/org/stellar/sdk/TimeBounds.java

@@ -11,24 +11,44 @@
 final public class TimeBounds {
 	final private long mMinTime;
 	final private long mMaxTime;
-	
+
 	/**
 	 * @param minTime 64bit Unix timestamp
 	 * @param maxTime 64bit Unix timestamp
 	 */
 	public TimeBounds(long minTime, long maxTime) {
-		if (maxTime > 0 && minTime >= maxTime) {
+		if (minTime < 0) {
+			throw new IllegalArgumentException("minTime cannot be negative");
+		}
+
+		if (maxTime < 0) {
+			throw new IllegalArgumentException("maxTime cannot be negative");
+		}
+
+		if (maxTime != 0 && minTime > maxTime) {
 			throw new IllegalArgumentException("minTime must be >= maxTime");
 		}
-		
+
 		mMinTime = minTime;
 		mMaxTime = maxTime;
 	}
-
+
+	/**
+	 * A factory method that sets maxTime to the specified second from now.
+	 *
+	 * @param timeout Timeout in seconds.
+	 * @return TimeBounds
+	 */
+	public static TimeBounds expiresAfter(long timeout) {
+		long now = System.currentTimeMillis() / 1000L;
+		long endTime = now + timeout;
+		return new TimeBounds(0, endTime);
+	}
+
 	public long getMinTime() {
 		return mMinTime;
 	}
-	
+
 	public long getMaxTime() {
 		return mMaxTime;
 	}
@@ -39,8 +59,8 @@ public static TimeBounds fromXdr(org.stellar.sdk.xdr.TimeBounds timeBounds) {
 		}
 
 		return new TimeBounds(
-				timeBounds.getMinTime().getTimePoint().getUint64().longValue(),
-				timeBounds.getMaxTime().getTimePoint().getUint64().longValue()
+				timeBounds.getMinTime().getTimePoint().getUint64(),
+				timeBounds.getMaxTime().getTimePoint().getUint64()
 		);
 	}
 
@@ -61,13 +81,14 @@ public org.stellar.sdk.xdr.TimeBounds toXdr() {
 
 	@Override
 	public boolean equals(Object o) {
-		if (this == o) return true;
-		if (o == null || getClass() != o.getClass()) return false;
-
+		if (this == o) {
+			return true;
+		}
+		if (o == null || getClass() != o.getClass()) {
+			return false;
+		}
 		TimeBounds that = (TimeBounds) o;
-
-		if (mMinTime != that.mMinTime) return false;
-		return mMaxTime == that.mMaxTime;
+		return mMinTime == that.mMinTime && mMaxTime == that.mMaxTime;
 	}
 
 

src/test/java/org/stellar/sdk/TimeBoundsTest.java

@@ -0,0 +1,75 @@
+package org.stellar.sdk;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class TimeBoundsTest {
+    @Test
+    public void testSetTimeBoundsNegativeMinTime() {
+        try {
+            new TimeBounds(-1, 300);
+            fail();
+        } catch (IllegalArgumentException e) {
+            assertEquals("minTime cannot be negative", e.getMessage());
+        }
+    }
+
+    @Test
+    public void testSetTimeBoundsNegativeMaxTime() {
+        try {
+            new TimeBounds(1, -300);
+            fail();
+        } catch (IllegalArgumentException e) {
+            assertEquals("maxTime cannot be negative", e.getMessage());
+        }
+    }
+
+    @Test
+    public void testSetTimeBoundsMinTimeGreatThanMaxTime() {
+        try {
+            new TimeBounds(300, 1);
+            fail();
+        } catch (IllegalArgumentException e) {
+            assertEquals("minTime must be >= maxTime", e.getMessage());
+        }
+    }
+
+    @Test
+    public void TestSetTimeoutInfinite() {
+        TimeBounds timebounds = new TimeBounds(300, 0);
+        assertEquals(300, timebounds.getMinTime());
+        assertEquals(0, timebounds.getMaxTime());
+    }
+
+    @Test
+    public void TestSetTimeoutInfiniteBothZero() {
+        TimeBounds timebounds = new TimeBounds(0, 0);
+        assertEquals(0, timebounds.getMinTime());
+        assertEquals(0, timebounds.getMaxTime());
+    }
+
+    @Test
+    public void TestSetTimeout() {
+        TimeBounds timebounds = new TimeBounds(1, 300);
+        assertEquals(1, timebounds.getMinTime());
+        assertEquals(300, timebounds.getMaxTime());
+    }
+
+    @Test
+    public void TestSetTimeoutMinEqualMax() {
+        TimeBounds timebounds = new TimeBounds(300, 300);
+        assertEquals(300, timebounds.getMinTime());
+        assertEquals(300, timebounds.getMaxTime());
+    }
+
+    @Test
+    public void TestTimeoutWithTimeout() {
+        long timeout = 300;
+        TimeBounds timebounds = TimeBounds.expiresAfter(timeout);
+        long now = System.currentTimeMillis() / 1000L;
+        assertEquals(0, timebounds.getMinTime());
+        assertTrue(timebounds.getMaxTime() - timeout <= now && timebounds.getMaxTime() - timeout >= now - 1);
+    }
+}
+