1 files changed, 102 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/util/MapBackedMemoryView.java b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/util/MapBackedMemoryView.java
new file mode 100644
index 00000000..3be078bd
--- /dev/null
+++ b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/util/MapBackedMemoryView.java
@@ -0,0 +1,102 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2018, Gabor Bergmann, IncQuery Labs Ltd.
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-v20.html.
+ * 
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package tools.refinery.viatra.runtime.matchers.util;
+
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.function.BiConsumer;
+
+/**
+ * Wraps a Map<T, Integer> (mapping elements to non-zero multiplicities) into an {@link IMemoryView}.
+ * 
+ * @author Gabor Bergmann
+ * @since 2.0
+ */
+public class MapBackedMemoryView<T> implements IMemoryView<T> {
+
+    private Map<T, Integer> wrapped;
+
+    /**
+     * @param wrapped an equivalent map from contained objects to multiplicities
+     */
+    protected MapBackedMemoryView(Map<T, Integer> wrapped) {
+        super();
+        this.wrapped = wrapped;
+    }
+
+    @Override
+    public Iterator<T> iterator() {
+        return wrapped.keySet().iterator();
+    }
+
+    @Override
+    public int getCount(T value) {
+        return getCountUnsafe(value);
+    }
+
+    @Override
+    public int getCountUnsafe(Object value) {
+        Integer count = wrapped.get(value);
+        return count == null ? 0 : count;
+    }
+
+    @Override
+    public boolean containsNonZero(T value) {
+        return wrapped.containsKey(value);
+    }
+
+    @Override
+    public boolean containsNonZeroUnsafe(Object value) {
+        return wrapped.containsKey(value);
+    }
+
+    @Override
+    public int size() {
+        return wrapped.size();
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return wrapped.isEmpty();
+    }
+
+    @Override
+    public Set<T> distinctValues() {
+        return wrapped.keySet();
+    }
+    
+    
+    @Override
+    public void forEachEntryWithMultiplicities(BiConsumer<T, Integer> entryConsumer) {
+        for (Entry<T, Integer> entry : wrapped.entrySet()) {
+            entryConsumer.accept(entry.getKey(), entry.getValue());
+        }
+    }
+    
+    @Override
+    public Iterable<Entry<T, Integer>> entriesWithMultiplicities() {
+        return wrapped.entrySet();
+    }
+    
+    @Override
+    public int hashCode() {
+        return IMemoryView.hashCode(this);
+    }
+    @Override
+    public boolean equals(Object obj) {
+        return IMemoryView.equals(this, obj);
+    }
+    
+    @Override
+    public String toString() {
+        return wrapped.toString();
+    }
+}