From ed2b70b976d0a4cf2c6739c41cb59ac3e2171b72 Mon Sep 17 00:00:00 2001
From: Josh Micich <josh@apache.org>
Date: Wed, 3 Dec 2008 05:07:31 +0000
Subject: [PATCH] modified EvaluationCell to make Evaluation API more easily
 wrapable.

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@722778 13f79535-47bb-0310-9956-ffa450edef68
---
 .../poi/hssf/usermodel/HSSFEvaluationCell.java  | 13 +++++--------
 .../apache/poi/ss/formula/EvaluationCell.java   | 11 +++++++----
 .../apache/poi/ss/formula/FormulaCellCache.java | 12 ++++++------
 .../poi/xssf/usermodel/XSSFEvaluationCell.java  | 17 +++++++----------
 4 files changed, 25 insertions(+), 28 deletions(-)

diff --git a/src/java/org/apache/poi/hssf/usermodel/HSSFEvaluationCell.java b/src/java/org/apache/poi/hssf/usermodel/HSSFEvaluationCell.java
index 97b581724..66069f8cb 100644
--- a/src/java/org/apache/poi/hssf/usermodel/HSSFEvaluationCell.java
+++ b/src/java/org/apache/poi/hssf/usermodel/HSSFEvaluationCell.java
@@ -34,15 +34,12 @@ final class HSSFEvaluationCell implements EvaluationCell {
 		_evalSheet = evalSheet;
 	}
 	public HSSFEvaluationCell(HSSFCell cell) {
-		_cell = cell;
-		_evalSheet = new HSSFEvaluationSheet(cell.getSheet());
+		this(cell, new HSSFEvaluationSheet(cell.getSheet()));
 	}
-	// Note -  hashCode and equals defined according to underlying cell
-	public int hashCode() {
-		return _cell.hashCode();
-	}
-	public boolean equals(Object obj) {
-		return _cell == ((HSSFEvaluationCell)obj)._cell;
+	public Object getIdentityKey() {
+		// save memory by just using the cell itself as the identity key
+		// Note - this assumes HSSFCell has not overridden hashCode and equals
+		return _cell;
 	}
 
 	public HSSFCell getHSSFCell() {
diff --git a/src/java/org/apache/poi/ss/formula/EvaluationCell.java b/src/java/org/apache/poi/ss/formula/EvaluationCell.java
index b1f467c5c..e22593406 100644
--- a/src/java/org/apache/poi/ss/formula/EvaluationCell.java
+++ b/src/java/org/apache/poi/ss/formula/EvaluationCell.java
@@ -17,19 +17,22 @@
 
 package org.apache.poi.ss.formula;
 
+import java.util.HashMap;
+
 /**
  * Abstracts a cell for the purpose of formula evaluation.  This interface represents both formula
  * and non-formula cells.<br/>
  * 
- * Implementors of this class must implement {@link Object#hashCode()} and {@link Object#equals(Object)}
- * to provide an <em>identity</em> relationship based on the underlying HSSF or XSSF cell <p/>
- * 
  * For POI internal use only
  * 
  * @author Josh Micich
  */
 public interface EvaluationCell {
-	// consider method Object getUnderlyingCell() to reduce memory consumption in formula cell cache
+	/**
+	 * @return an Object that identifies the underlying cell, suitable for use as a key in a {@link HashMap}
+	 */
+	Object getIdentityKey();
+
 	EvaluationSheet getSheet();
 	int getRowIndex();
 	int getColumnIndex();
diff --git a/src/java/org/apache/poi/ss/formula/FormulaCellCache.java b/src/java/org/apache/poi/ss/formula/FormulaCellCache.java
index 4a1fce6b8..81cd4d468 100644
--- a/src/java/org/apache/poi/ss/formula/FormulaCellCache.java
+++ b/src/java/org/apache/poi/ss/formula/FormulaCellCache.java
@@ -31,11 +31,11 @@ final class FormulaCellCache {
 		void processEntry(FormulaCellCacheEntry entry);
 	}
 
-	private Map _formulaEntriesByCell;
+	private final Map<Object, FormulaCellCacheEntry> _formulaEntriesByCell;
 
 	public FormulaCellCache() {
-		// assumes HSSFCell does not override hashCode or equals, otherwise we need IdentityHashMap
-		_formulaEntriesByCell = new HashMap(); 
+		// assumes the object returned by EvaluationCell.getIdentityKey() has a well behaved hashCode+equals
+		_formulaEntriesByCell = new HashMap<Object, FormulaCellCacheEntry>();
 	}
 
 	public CellCacheEntry[] getCacheEntries() {
@@ -53,15 +53,15 @@ final class FormulaCellCache {
 	 * @return <code>null</code> if not found
 	 */
 	public FormulaCellCacheEntry get(EvaluationCell cell) {
-		return (FormulaCellCacheEntry) _formulaEntriesByCell.get(cell);
+		return _formulaEntriesByCell.get(cell.getIdentityKey());
 	}
 
 	public void put(EvaluationCell cell, FormulaCellCacheEntry entry) {
-		_formulaEntriesByCell.put(cell, entry);
+		_formulaEntriesByCell.put(cell.getIdentityKey(), entry);
 	}
 
 	public FormulaCellCacheEntry remove(EvaluationCell cell) {
-		return (FormulaCellCacheEntry) _formulaEntriesByCell.remove(cell);
+		return _formulaEntriesByCell.remove(cell.getIdentityKey());
 	}
 
 	public void applyOperation(IEntryOperation operation) {
diff --git a/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFEvaluationCell.java b/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFEvaluationCell.java
index 0f78ef6a4..127e4da86 100644
--- a/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFEvaluationCell.java
+++ b/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFEvaluationCell.java
@@ -30,22 +30,19 @@ final class XSSFEvaluationCell implements EvaluationCell {
 	private final EvaluationSheet _evalSheet;
 	private final XSSFCell _cell;
 
-	public XSSFEvaluationCell(XSSFCell cell) {
-		_cell = cell;
-		_evalSheet = new XSSFEvaluationSheet(cell.getSheet());
-	}
-
 	public XSSFEvaluationCell(XSSFCell cell, XSSFEvaluationSheet evaluationSheet) {
 		_cell = cell;
 		_evalSheet = evaluationSheet;
 	}
 
-	// Note -  hashCode and equals defined according to underlying cell
-	public int hashCode() {
-		return _cell.hashCode();
+	public XSSFEvaluationCell(XSSFCell cell) {
+		this(cell, new XSSFEvaluationSheet(cell.getSheet()));
 	}
-	public boolean equals(Object obj) {
-		return _cell == ((XSSFEvaluationCell)obj)._cell;
+
+	public Object getIdentityKey() {
+		// save memory by just using the cell itself as the identity key
+		// Note - this assumes HSSFCell has not overridden hashCode and equals
+		return _cell;
 	}
 
 	public XSSFCell getXSSFCell() {