Lower SchemaPath#getPath() memory overhead

[yangtools.git] / yang / yang-model-api / src / main / java / org / opendaylight / yangtools / yang / model / api / SchemaPath.java

diff --git a/yang/yang-model-api/src/main/java/org/opendaylight/yangtools/yang/model/api/SchemaPath.java b/yang/yang-model-api/src/main/java/org/opendaylight/yangtools/yang/model/api/SchemaPath.java
index 7bae5f0f57daf182827fbcedbc5d045689ef62f7..fd4466d0343c7ac21c6634c8e896db72441c70ad 100644 (file)
--- a/yang/yang-model-api/src/main/java/org/opendaylight/yangtools/yang/model/api/SchemaPath.java
+++ b/yang/yang-model-api/src/main/java/org/opendaylight/yangtools/yang/model/api/SchemaPath.java
@@ -7,17 +7,20 @@
  */
 package org.opendaylight.yangtools.yang.model.api;
 
-import com.google.common.base.Objects;
-import com.google.common.base.Objects.ToStringHelper;
+import com.google.common.base.MoreObjects;
+import com.google.common.base.MoreObjects.ToStringHelper;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
-
+import com.google.common.collect.Lists;
+import com.google.common.collect.UnmodifiableIterator;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
-
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
 import org.opendaylight.yangtools.concepts.Immutable;
 import org.opendaylight.yangtools.yang.common.QName;
 
@@ -25,6 +28,7 @@ import org.opendaylight.yangtools.yang.common.QName;
  * Represents unique path to the every node inside the module.
  */
 public abstract class SchemaPath implements Immutable {
+
     /**
      * An absolute SchemaPath.
      */
@@ -40,7 +44,7 @@ public abstract class SchemaPath implements Immutable {
 
         @Override
         protected SchemaPath createInstance(final SchemaPath parent, final QName qname) {
-            return new AbsoluteSchemaPath(parent, qname);
+            return new AbsoluteSchemaPath(parent, Preconditions.checkNotNull(qname));
         }
     }
 
@@ -59,10 +63,14 @@ public abstract class SchemaPath implements Immutable {
 
         @Override
         protected SchemaPath createInstance(final SchemaPath parent, final QName qname) {
-            return new RelativeSchemaPath(parent, qname);
+            return new RelativeSchemaPath(parent, Preconditions.checkNotNull(qname));
         }
     }
 
+    @SuppressWarnings("rawtypes")
+    private static final AtomicReferenceFieldUpdater<SchemaPath, ImmutableList> LEGACYPATH_UPDATER =
+            AtomicReferenceFieldUpdater.newUpdater(SchemaPath.class, ImmutableList.class, "legacyPath");
+
     /**
      * Shared instance of the conceptual root schema node.
      */
@@ -92,14 +100,38 @@ public abstract class SchemaPath implements Immutable {
      * Cached legacy path, filled-in when {@link #getPath()} or {@link #getPathTowardsRoot()}
      * is invoked.
      */
-    private ImmutableList<QName> legacyPath;
+    private volatile ImmutableList<QName> legacyPath;
+
+    /**
+     * @deprecated This constructor will be hidden in a future release.
+     * @param parent
+     * @param qname
+     */
+    @Deprecated
+    protected SchemaPath(final SchemaPath parent, final QName qname) {
+        this.parent = parent;
+        this.qname = qname;
+
+        int h = Objects.hashCode(parent);
+        if (qname != null) {
+            h = h * 31 + qname.hashCode();
+        }
+
+        hash = h;
+    }
 
     private ImmutableList<QName> getLegacyPath() {
-        if (legacyPath == null) {
-            legacyPath = ImmutableList.copyOf(getPathTowardsRoot()).reverse();
+        ImmutableList<QName> ret = legacyPath;
+        if (ret == null) {
+            final List<QName> tmp = new ArrayList<>();
+            for (QName qname : getPathTowardsRoot()) {
+                tmp.add(qname);
+            }
+            ret = ImmutableList.copyOf(Lists.reverse(tmp));
+            LEGACYPATH_UPDATER.lazySet(this, ret);
         }
 
-        return legacyPath;
+        return ret;
     }
 
     /**
@@ -115,18 +147,6 @@ public abstract class SchemaPath implements Immutable {
         return getLegacyPath();
     }
 
-    protected SchemaPath(final SchemaPath parent, final QName qname) {
-        this.parent = parent;
-        this.qname = qname;
-
-        int h = parent == null ? 0 : parent.hashCode();
-        if (qname != null) {
-            h = h * 31 + qname.hashCode();
-        }
-
-        hash = h;
-    }
-
     /**
      * Constructs new instance of this class with the concrete path.
      *
@@ -163,8 +183,8 @@ public abstract class SchemaPath implements Immutable {
     /**
      * Create a new instance.
      *
-     * @param path path from root
-     * @param hash intended hash code
+     * @param parent Parent SchemaPath
+     * @param qname next path element
      * @return A new SchemaPath instance
      */
     protected abstract SchemaPath createInstance(SchemaPath parent, QName qname);
@@ -180,12 +200,12 @@ public abstract class SchemaPath implements Immutable {
             return this;
         }
 
-        SchemaPath parent = this;
+        SchemaPath parentPath = this;
         for (QName qname : relative) {
-            parent = parent.createInstance(parent, qname);
+            parentPath = parentPath.createInstance(parentPath, qname);
         }
 
-        return parent;
+        return parentPath;
     }
 
     /**
@@ -197,12 +217,12 @@ public abstract class SchemaPath implements Immutable {
     public SchemaPath createChild(final SchemaPath relative) {
         Preconditions.checkArgument(!relative.isAbsolute(), "Child creation requires relative path");
 
-        SchemaPath parent = this;
+        SchemaPath parentPath = this;
         for (QName qname : relative.getPathFromRoot()) {
-            parent = parent.createInstance(parent, qname);
+            parentPath = parentPath.createInstance(parentPath, qname);
         }
 
-        return parent;
+        return parentPath;
     }
 
     /**
@@ -239,7 +259,7 @@ public abstract class SchemaPath implements Immutable {
         return new Iterable<QName>() {
             @Override
             public Iterator<QName> iterator() {
-                return new Iterator<QName>() {
+                return new UnmodifiableIterator<QName>() {
                     private SchemaPath current = SchemaPath.this;
 
                     @Override
@@ -257,11 +277,6 @@ public abstract class SchemaPath implements Immutable {
                             throw new NoSuchElementException("No more elements available");
                         }
                     }
-
-                    @Override
-                    public void remove() {
-                        throw new UnsupportedOperationException("Component removal not supported");
-                    }
                 };
             }
         };
@@ -310,26 +325,12 @@ public abstract class SchemaPath implements Immutable {
             return false;
         }
         final SchemaPath other = (SchemaPath) obj;
-
-        if (qname != null) {
-            if (!qname.equals(other.qname)) {
-                return false;
-            }
-        } else {
-            if (other.qname != null) {
-                return false;
-            }
-        }
-
-        if (parent == null) {
-            return other.parent == null;
-        }
-        return parent.equals(other.parent);
+        return Objects.equals(qname, other.qname) && Objects.equals(parent, other.parent);
     }
 
     @Override
     public final String toString() {
-        return addToStringAttributes(Objects.toStringHelper(this)).toString();
+        return addToStringAttributes(MoreObjects.toStringHelper(this)).toString();
     }
 
     protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {