less disk operations in integrate

jps/model/src/org/jetbrains/ether/dependencyView/Mappings.java

@@ -1650,40 +1650,46 @@ public class Mappings {
 
         if (delta.isDifferentiated()) {
           for (DependencyContext.S c : delta.getChangedClasses()) {
-            myClassToSubclasses.remove(c);
-
             final Collection<DependencyContext.S> subClasses = delta.myClassToSubclasses.get(c);
-
             if (subClasses != null) {
-              myClassToSubclasses.put(c, subClasses);
+              myClassToSubclasses.replace(c, subClasses);
+            }
+            else {
+              myClassToSubclasses.remove(c);
             }
 
-            myClassToSourceFile.remove(c);
-
             final DependencyContext.S sourceFile = delta.myClassToSourceFile.get(c);
-
             if (sourceFile != null) {
               myClassToSourceFile.put(c, sourceFile);
             }
+            else {
+              myClassToSourceFile.remove(c);
+            }
           }
 
           for (DependencyContext.S f : delta.getChangedFiles()) {
-            mySourceFileToClasses.remove(f);
             final Collection<ClassRepr> classes = delta.mySourceFileToClasses.get(f);
             if (classes != null) {
-              mySourceFileToClasses.put(f, classes);
+              mySourceFileToClasses.replace(f, classes);
+            }
+            else {
+              mySourceFileToClasses.remove(f);
             }
 
-            mySourceFileToUsages.remove(f);
             final Collection<UsageRepr.Cluster> clusters = delta.mySourceFileToUsages.get(f);
             if (clusters != null) {
-              mySourceFileToUsages.put(f, clusters);
+              mySourceFileToUsages.replace(f, clusters);
+            }
+            else {
+              mySourceFileToUsages.remove(f);
             }
 
-            mySourceFileToAnnotationUsages.remove(f);
             final Collection<UsageRepr.Usage> usages = delta.mySourceFileToAnnotationUsages.get(f);
             if (usages != null) {
-              mySourceFileToAnnotationUsages.put(f, usages);
+              mySourceFileToAnnotationUsages.replace(f, usages);
+            }
+            else {
+              mySourceFileToAnnotationUsages.remove(f);
             }
           }
         }
@@ -1728,8 +1734,7 @@ public class Mappings {
             changed |= past.addAll(now);
 
             if (changed) {
-              myClassToClassDependency.remove(aClass);
-              myClassToClassDependency.put(aClass, past);
+              myClassToClassDependency.replace(aClass, past);
             }
           }
         }

jps/model/src/org/jetbrains/ether/dependencyView/MultiMaplet.java

@@ -30,6 +30,7 @@ interface MultiMaplet<K, V> {
   Collection<V> get(final K key);
   void put(final K key, final V value);
   void put(final K key, final Collection<V> value);
+  void replace(final K key, final Collection<V> value);
   void putAll(MultiMaplet<K,V> m);
   void replaceAll(MultiMaplet<K, V> m);
   void remove(final K key);

jps/model/src/org/jetbrains/ether/dependencyView/PersistentMultiMaplet.java

@@ -66,6 +66,21 @@ class PersistentMultiMaplet<K, V> implements MultiMaplet<K, V> {
     }
   }
 
+  @Override
+  public void replace(K key, Collection<V> value) {
+    try {
+      if (value == null || value.isEmpty()) {
+        myMap.remove(key);
+      }
+      else {
+        myMap.put(key, value);
+      }
+    }
+    catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
   @Override
   public void put(final K key, final Collection<V> value) {
     try {
@@ -149,9 +164,7 @@ class PersistentMultiMaplet<K, V> implements MultiMaplet<K, V> {
   @Override
   public void replaceAll(MultiMaplet<K, V> m) {
     for (Map.Entry<K, Collection<V>> entry : m.entrySet()) {
-      final K key = entry.getKey();
-      remove(key);
-      put(key, entry.getValue());
+      replace(entry.getKey(), entry.getValue());
     }
   }
 

jps/model/src/org/jetbrains/ether/dependencyView/TransientMultiMaplet.java

@@ -72,6 +72,16 @@ class TransientMultiMaplet<K, V> implements MultiMaplet<K, V> {
     }
   }
 
+  @Override
+  public void replace(K key, Collection<V> value) {
+    if (value == null || value.isEmpty()) {
+      myMap.remove(key);
+    }
+    else {
+      myMap.put(key, value);
+    }
+  }
+
   @Override
   public void put(final K key, final V value) {
     final Collection<V> x = constr.create();
@@ -111,8 +121,7 @@ class TransientMultiMaplet<K, V> implements MultiMaplet<K, V> {
   @Override
   public void replaceAll(MultiMaplet<K, V> m) {
     for (Map.Entry<K, Collection<V>> e : m.entrySet()) {
-      remove(e.getKey());
-      put(e.getKey(), e.getValue());
+      replace(e.getKey(), e.getValue());
     }
   }