Override equals() and hashCode() in BannedElement (#1510)

* add equals and hashcode to BannedElement

* address review

* address review

* address review

Author: abbiefarr

plugins/com.google.cloud.tools.eclipse.appengine.validation.test/src/com/google/cloud/tools/eclipse/appengine/validation/BannedElementTest.java

@@ -16,6 +16,10 @@
 
 package com.google.cloud.tools.eclipse.appengine.validation;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
 import org.junit.Test;
 
 public class BannedElementTest {
@@ -29,6 +33,45 @@ public void testBannedElementConstructor_nullElementName() {
   public void testBannedElementConstructor_nullLocation() {
     new BannedElement("test", "org.eclipse.core.resources.problemmarker", 1, null, 0);
   }
+  
+  @Test
+  public void testEquals() {
+    BannedElement element1 = new BannedElement("message");
+    BannedElement element1_copy = element1;
+    assertTrue(element1.equals(element1_copy));
+    
+    BannedElement element2 = new BannedElement("message");
+    assertTrue(element1.equals(element2));
+    assertTrue(element2.equals(element1));
+    
+    BannedElement element3 =
+        new BannedElement("message", "markerId_1", 13, new DocumentLocation(1, 1), 20);
+    BannedElement element4 =
+        new BannedElement("message", "markerId_2", 13, new DocumentLocation(1, 1), 20);
+    assertFalse(element3.equals(element4));
+    
+    BannedElement element5 =
+        new BannedElement("message", "markerId", 13, new DocumentLocation(1, 1), 20);
+    BannedElement element6 =
+        new BannedElement("message", "markerId", 13, new DocumentLocation(1, 15), 20);
+    assertFalse(element5.equals(element6));
+    
+    BannedElement element7 =
+        new BannedElement("message_1", "markerId", 13, new DocumentLocation(1, 1), 20);
+    BannedElement element8 =
+        new BannedElement("message_2", "markerId", 13, new DocumentLocation(1, 1), 20);
+    assertFalse(element7.equals(element8));
+    
+    assertFalse(element1.equals(null));
+    assertFalse(element1.equals("test"));
+  }
+  
+  @Test
+  public void testHashCode() {
+    BannedElement element1 = new BannedElement("message");
+    BannedElement element2 = new BannedElement("message");
+    assertEquals(element1.hashCode(), element2.hashCode());
+  }
 
 }
 

plugins/com.google.cloud.tools.eclipse.appengine.validation/src/com/google/cloud/tools/eclipse/appengine/validation/BannedElement.java

@@ -16,12 +16,14 @@
 
 package com.google.cloud.tools.eclipse.appengine.validation;
 
+import java.util.Objects;
+
 import com.google.common.base.Preconditions;
 
 /**
  * A blacklisted element that will receive a problem marker. 
  */
-public class BannedElement {
+class BannedElement {
 
   private final String message;
   private final DocumentLocation start;
@@ -33,7 +35,7 @@ public class BannedElement {
    * @param length the length of the marker underline. Length == 0 results in a
    *        marker in the vertical ruler and no underline
    */
-  public BannedElement(String message, String markerId, int severity,
+  BannedElement(String message, String markerId, int severity,
       DocumentLocation start, int length) {
     Preconditions.checkNotNull(message, "message is null");
     Preconditions.checkNotNull(markerId, "markerId is null");
@@ -46,20 +48,20 @@ public BannedElement(String message, String markerId, int severity,
     this.severity = severity;
   }
 
-  public BannedElement(String message) {
+  BannedElement(String message) {
     this(message, "org.eclipse.core.resources.problemmarker",
       1, new DocumentLocation(0, 0), 0);
   }
 
-  public String getMessage() {
+  String getMessage() {
     return message;
   }
 
-  public DocumentLocation getStart() {
+  DocumentLocation getStart() {
     return start;
   }
 
-  public int getLength() {
+  int getLength() {
     return length;
   }
 
@@ -70,5 +72,29 @@ String getMarkerId() {
   int getSeverity() {
     return severity;
   }
+  
+  /**
+   * BannedElements are equal if they represent the same marker type (marker ID),
+   * have the same location within a document, and will display the same message.
+   */
+  @Override
+  public boolean equals(Object object) {
+    if (object == this) {
+      return true;
+    }
+    if (object == null || !(object instanceof BannedElement)) {
+      return false;
+    } 
+    BannedElement element = (BannedElement) object;
+    return Objects.equals(markerId, element.getMarkerId()) &&
+        Objects.equals(message, element.getMessage()) &&
+        start.getLineNumber() == element.getStart().getLineNumber() &&
+        start.getColumnNumber() == element.getStart().getColumnNumber();
+  }
+  
+  @Override
+  public int hashCode() {
+    return Objects.hash(markerId, message, start.getLineNumber(), start.getColumnNumber());
+  }
 
 }