Small optimizations & MultiBlockBase cleanup (#3197)

Co-authored-by: Martin Robertz <dream-master@gmx.net>

1 files changed, 60 insertions, 0 deletions

diff --git a/src/main/java/gregtech/api/util/ValidMTEList.java b/src/main/java/gregtech/api/util/ValidMTEList.java
new file mode 100644
index 0000000000..95f4cd7ad0
--- /dev/null
+++ b/src/main/java/gregtech/api/util/ValidMTEList.java
@@ -0,0 +1,60 @@
+package gregtech.api.util;
+
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+import org.jetbrains.annotations.NotNull;
+
+import gregtech.api.metatileentity.MetaTileEntity;
+
+public class ValidMTEList<E extends Collection<T>, T extends MetaTileEntity> implements Iterable<T> {
+
+    private final E collection;
+
+    public ValidMTEList(E collection) {
+        this.collection = collection;
+    }
+
+    private class ValidMTEIterator implements Iterator<T> {
+
+        Iterator<T> iterator = collection.iterator();
+
+        T nextObject = null;
+        boolean nextObjectSet = false;
+
+        private boolean setNextObject() {
+            while (iterator.hasNext()) {
+                final T object = iterator.next();
+                if (object != null && object.isValid()) {
+                    nextObject = object;
+                    nextObjectSet = true;
+                    return true;
+                } else {
+                    iterator.remove();
+                }
+            }
+            return false;
+        }
+
+        @Override
+        public boolean hasNext() {
+            return nextObjectSet || setNextObject();
+        }
+
+        @Override
+        public T next() {
+            if (!nextObjectSet && !setNextObject()) {
+                throw new NoSuchElementException();
+            }
+            nextObjectSet = false;
+            return nextObject;
+
+        }
+    }
+
+    @Override
+    public @NotNull Iterator<T> iterator() {
+        return new ValidMTEIterator();
+    }
+}