### Question:
IndexFile { public boolean putKey(final String key, final long phyOffset, final long storeTimestamp) { if (this.indexHeader.getIndexCount() < this.indexNum) { int keyHash = indexKeyHashMethod(key); int slotPos = keyHash % this.hashSlotNum; int absSlotPos = IndexHeader.INDEX_HEADER_SIZE + slotPos * hashSlotSize; FileLock fileLock = null; try { int slotValue = this.mappedByteBuffer.getInt(absSlotPos); if (slotValue <= invalidIndex || slotValue > this.indexHeader.getIndexCount()) { slotValue = invalidIndex; } long timeDiff = storeTimestamp - this.indexHeader.getBeginTimestamp(); timeDiff = timeDiff / 1000; if (this.indexHeader.getBeginTimestamp() <= 0) { timeDiff = 0; } else if (timeDiff > Integer.MAX_VALUE) { timeDiff = Integer.MAX_VALUE; } else if (timeDiff < 0) { timeDiff = 0; } int absIndexPos = IndexHeader.INDEX_HEADER_SIZE + this.hashSlotNum * hashSlotSize + this.indexHeader.getIndexCount() * indexSize; this.mappedByteBuffer.putInt(absIndexPos, keyHash); this.mappedByteBuffer.putLong(absIndexPos + 4, phyOffset); this.mappedByteBuffer.putInt(absIndexPos + 4 + 8, (int)timeDiff); this.mappedByteBuffer.putInt(absIndexPos + 4 + 8 + 4, slotValue); this.mappedByteBuffer.putInt(absSlotPos, this.indexHeader.getIndexCount()); if (this.indexHeader.getIndexCount() <= 1) { this.indexHeader.setBeginPhyOffset(phyOffset); this.indexHeader.setBeginTimestamp(storeTimestamp); } this.indexHeader.incHashSlotCount(); this.indexHeader.incIndexCount(); this.indexHeader.setEndPhyOffset(phyOffset); this.indexHeader.setEndTimestamp(storeTimestamp); return true; } catch (Exception e) { log.error("putKey exception, Key: " + key + " KeyHashCode: " + key.hashCode(), e); } finally { if (fileLock != null) { try { fileLock.release(); } catch (IOException e) { e.printStackTrace(); } } } } else { log.warn("Over index file capacity: index count = " + this.indexHeader.getIndexCount() + "; index max num = " + this.indexNum); } return false; } IndexFile(final String fileName, final int hashSlotNum, final int indexNum,
                     final long endPhyOffset, final long endTimestamp); String getFileName(); void load(); void flush(); boolean isWriteFull(); boolean destroy(final long intervalForcibly); boolean putKey(final String key, final long phyOffset, final long storeTimestamp); int indexKeyHashMethod(final String key); long getBeginTimestamp(); long getEndTimestamp(); long getEndPhyOffset(); boolean isTimeMatched(final long begin, final long end); void selectPhyOffset(final List<Long> phyOffsets, final String key, final int maxNum,
                                final long begin, final long end, boolean lock);  }### Answer:
@Test public void testPutKey() throws Exception { IndexFile indexFile = new IndexFile("100", HASH_SLOT_NUM, INDEX_NUM, 0, 0); for (long i = 0; i < (INDEX_NUM - 1); i++) { boolean putResult = indexFile.putKey(Long.toString(i), i, System.currentTimeMillis()); assertThat(putResult).isTrue(); } boolean putResult = indexFile.putKey(Long.toString(400), 400, System.currentTimeMillis()); assertThat(putResult).isFalse(); indexFile.destroy(0); }