From be261fa65a128900b04abe58d3bc5daeadaefc5e Mon Sep 17 00:00:00 2001
From: Dmitry Shmatko <zilm@zilm.net>
Date: Wed, 18 Apr 2018 16:31:18 +0300
Subject: [PATCH] Polishing RecommendedGasPriceTracker

---
 .../java/org/ethereum/facade/Ethereum.java    |  1 +
 .../listener/RecommendedGasPriceTracker.java  | 27 ++++++++-----------
 2 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/ethereumj-core/src/main/java/org/ethereum/facade/Ethereum.java b/ethereumj-core/src/main/java/org/ethereum/facade/Ethereum.java
index aec5c8e99a..0fcd872280 100644
--- a/ethereumj-core/src/main/java/org/ethereum/facade/Ethereum.java
+++ b/ethereumj-core/src/main/java/org/ethereum/facade/Ethereum.java
@@ -202,6 +202,7 @@ ProgramResult callConstantFunction(String receiveAddress, ECKey senderPrivateKey
     void initSyncing();
 
     /**
+     * @deprecated
      * Calculates a 'reasonable' Gas price based on statistics of the latest transaction's Gas prices
      * Normally the price returned should be sufficient to execute a transaction since ~25% of the latest
      * transactions were executed at this or lower price.
diff --git a/ethereumj-core/src/main/java/org/ethereum/listener/RecommendedGasPriceTracker.java b/ethereumj-core/src/main/java/org/ethereum/listener/RecommendedGasPriceTracker.java
index 02f7b97a95..1d5ab57ef0 100644
--- a/ethereumj-core/src/main/java/org/ethereum/listener/RecommendedGasPriceTracker.java
+++ b/ethereumj-core/src/main/java/org/ethereum/listener/RecommendedGasPriceTracker.java
@@ -17,7 +17,6 @@
  */
 package org.ethereum.listener;
 
-import org.apache.commons.collections4.queue.CircularFifoQueue;
 import org.ethereum.core.Block;
 import org.ethereum.core.BlockSummary;
 import org.ethereum.core.Transaction;
@@ -25,6 +24,7 @@
 
 import java.lang.reflect.Array;
 import java.util.Arrays;
+import java.util.LinkedList;
 import java.util.List;
 
 
@@ -46,15 +46,11 @@ public class RecommendedGasPriceTracker extends EthereumListenerAdapter {
     private static final int MIN_TRANSACTIONS = 512;
     private static final int PERCENTILE_SHARE = 4;
 
-    private CircularFifoQueue<long[]> blockGasPrices;
+    private LinkedList<long[]> blockGasPrices = new LinkedList<>();
 
     private int idx = 0;
     private Long recommendedGasPrice = getDefaultPrice();
 
-    public RecommendedGasPriceTracker() {
-        blockGasPrices = new CircularFifoQueue<>(Math.max(getMinTransactions(), getMinBlocks()));
-    }
-
     @Override
     public void onBlock(BlockSummary blockSummary) {
         onBlock(blockSummary.getBlock());
@@ -63,7 +59,7 @@ public void onBlock(BlockSummary blockSummary) {
     private void onBlock(Block block) {
         if (onTransactions(block.getTransactionsList())) {
             ++idx;
-            if (idx == getBlocksRecount()) {
+            if (idx >= getBlocksRecount()) {
                 Long newGasPrice = getGasPrice();
                 if (newGasPrice != null) {
                     this.recommendedGasPrice = newGasPrice;
@@ -81,11 +77,11 @@ private synchronized boolean onTransactions(List<Transaction> txs) {
             gasPrices[i] = ByteUtil.byteArrayToLong(txs.get(i).getGasPrice());
         }
 
-        while (blockGasPrices.size() >= getMinBlocks() &&
-                (calcGasPricesSize() - blockGasPrices.get(0).length + gasPrices.length) >= getMinTransactions()) {
-            blockGasPrices.remove(blockGasPrices.get(0));
-        }
         blockGasPrices.add(gasPrices);
+        while (blockGasPrices.size() > getMinBlocks() &&
+                (calcGasPricesSize() - blockGasPrices.getFirst().length + gasPrices.length) >= getMinTransactions()) {
+            blockGasPrices.removeFirst();
+        }
         return true;
     }
 
@@ -99,11 +95,10 @@ private synchronized Long getGasPrice() {
         if (size < getMinTransactions() ||
                 blockGasPrices.size() < getMinBlocks()) return null;
 
-        long[] difficulties = new long[size > getMinTransactions() ? size : getMinTransactions()];
+        long[] difficulties = new long[size];
         int index = 0;
-        for (int i = 0; i < blockGasPrices.size(); ++i) {
-            long[] current = blockGasPrices.get(i);
-            for (long currentDifficulty : current) {
+        for (long[] currentBlock : blockGasPrices) {
+            for (long currentDifficulty : currentBlock) {
                 difficulties[index] = currentDifficulty;
                 ++index;
             }
@@ -176,4 +171,4 @@ public static int getMinTransactions() {
     public static int getPercentileShare() {
         return PERCENTILE_SHARE;
     }
-}
\ No newline at end of file
+}