1 files changed, 93 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/util/EclipseCollectionsMultiset.java b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/util/EclipseCollectionsMultiset.java
new file mode 100644
index 00000000..46977c8b
--- /dev/null
+++ b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/util/EclipseCollectionsMultiset.java
@@ -0,0 +1,93 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2017, Gabor Bergmann, IncQueryLabs 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;
+
+/**
+ * @author Gabor Bergmann
+ * @since 1.7
+ */
+public class EclipseCollectionsMultiset<T> extends EclipseCollectionsBagMemory<T> implements IMultiset<T> {
+
+    @Override
+    public boolean addOne(T value) {
+        int oldCount = super.getIfAbsent(value, 0);
+
+        super.put(value, oldCount + 1);
+
+        return oldCount == 0;
+    }
+
+    @Override
+    public boolean addPositive(T value, int count) {
+        if (count < 0) {
+            throw new IllegalArgumentException("The count value must be positive!");
+        }
+
+        int oldCount = super.getIfAbsent(value, 0);
+
+        super.put(value, oldCount + count);
+
+        return oldCount == 0;
+    }
+    
+    @Override
+    public boolean addSigned(T value, int count) {
+        int oldCount = super.getIfAbsent(value, 0);
+        int newCount = oldCount + count;
+        
+        boolean becomesZero = newCount == 0;
+        if (newCount < 0)
+            throw new IllegalStateException(String.format(
+                    "Cannot remove %d occurrences of value '%s' as only %d would remain in %s", 
+                    count, value, newCount, this));
+        else if (becomesZero)
+            super.removeKey(value);
+        else // (newCount > 0)
+            super.put(value, newCount);
+       
+        return becomesZero || oldCount == 0;
+    }
+    
+    
+    @Override
+    public boolean removeOne(T value) {
+        return removeOneInternal(value, true);
+    }
+    
+    @Override
+    public boolean removeOneOrNop(T value) {
+        return removeOneInternal(value, false);
+    }
+
+    /**
+     * @since 2.3
+     */
+    protected boolean removeOneInternal(T value, boolean throwIfImpossible) {
+        int oldCount = super.getIfAbsent(value, 0);
+        if (oldCount == 0) {
+            if (throwIfImpossible) throw new IllegalStateException(String.format(
+                    "Cannot remove value '%s' that is not contained in %s", 
+                    value, this));
+            else return false;
+        }
+        
+        int rest = oldCount - 1;
+        boolean empty = rest == 0;
+
+        if (!empty) {
+            super.put(value, rest);
+        } else {
+            super.remove(value);
+        }
+
+        return empty;
+    }
+    
+    
+}