immutable maps

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1921575 13f79535-47bb-0310-9956-ffa450edef68

8 files changed, 61 insertions, 45 deletions

diff --git a/poi/src/main/java/org/apache/poi/ddf/EscherPropertyTypes.java b/poi/src/main/java/org/apache/poi/ddf/EscherPropertyTypes.java
index a48972faf3..7502dbc974 100644
--- a/poi/src/main/java/org/apache/poi/ddf/EscherPropertyTypes.java
+++ b/poi/src/main/java/org/apache/poi/ddf/EscherPropertyTypes.java
@@ -17,6 +17,7 @@
 
 package org.apache.poi.ddf;
 
+import java.util.Collections;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Collectors;
@@ -365,8 +366,8 @@ public enum EscherPropertyTypes {
         return propNumber;
     }
 
-    private static final Map<Short, EscherPropertyTypes> LOOKUP =
-            Stream.of(values()).collect(Collectors.toMap(EscherPropertyTypes::getPropertyId, Function.identity()));
+    private static final Map<Short, EscherPropertyTypes> LOOKUP = Collections.unmodifiableMap(
+            Stream.of(values()).collect(Collectors.toMap(EscherPropertyTypes::getPropertyId, Function.identity())));
 
     public static EscherPropertyTypes forPropertyID(int propertyId) {
         EscherPropertyTypes rt = LOOKUP.get((short)(propertyId & 0x3FFF));
diff --git a/poi/src/main/java/org/apache/poi/ddf/EscherRecordTypes.java b/poi/src/main/java/org/apache/poi/ddf/EscherRecordTypes.java
index 4f11dab6c0..a8b589d7cb 100644
--- a/poi/src/main/java/org/apache/poi/ddf/EscherRecordTypes.java
+++ b/poi/src/main/java/org/apache/poi/ddf/EscherRecordTypes.java
@@ -17,6 +17,7 @@
 
 package org.apache.poi.ddf;
 
+import java.util.Collections;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.function.Supplier;
@@ -108,8 +109,8 @@ public enum EscherRecordTypes {
         return typeID;
     }
 
-    private static final Map<Short, EscherRecordTypes> LOOKUP =
-        Stream.of(values()).collect(Collectors.toMap(EscherRecordTypes::getTypeId, Function.identity()));
+    private static final Map<Short, EscherRecordTypes> LOOKUP = Collections.unmodifiableMap(
+        Stream.of(values()).collect(Collectors.toMap(EscherRecordTypes::getTypeId, Function.identity())));
 
     public static EscherRecordTypes forTypeID(int typeID) {
         // Section 2.2.23: 0xF02A is treated as 0xF01D
diff --git a/poi/src/main/java/org/apache/poi/hssf/record/HSSFRecordTypes.java b/poi/src/main/java/org/apache/poi/hssf/record/HSSFRecordTypes.java
index e8edcd9beb..cf96237be4 100644
--- a/poi/src/main/java/org/apache/poi/hssf/record/HSSFRecordTypes.java
+++ b/poi/src/main/java/org/apache/poi/hssf/record/HSSFRecordTypes.java
@@ -20,6 +20,7 @@
 package org.apache.poi.hssf.record;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Collectors;
@@ -211,8 +212,8 @@ public enum HSSFRecordTypes {
         T apply(RecordInputStream in);
     }
 
-    private static final Map<Short,HSSFRecordTypes> LOOKUP =
-        Arrays.stream(values()).collect(Collectors.toMap(HSSFRecordTypes::getSid, Function.identity()));
+    private static final Map<Short,HSSFRecordTypes> LOOKUP = Collections.unmodifiableMap(
+        Arrays.stream(values()).collect(Collectors.toMap(HSSFRecordTypes::getSid, Function.identity())));
 
     public final short sid;
     public final Class<? extends org.apache.poi.hssf.record.Record> clazz;
diff --git a/poi/src/main/java/org/apache/poi/hssf/record/SubRecord.java b/poi/src/main/java/org/apache/poi/hssf/record/SubRecord.java
index 230e47b16c..ca16540ec8 100644
--- a/poi/src/main/java/org/apache/poi/hssf/record/SubRecord.java
+++ b/poi/src/main/java/org/apache/poi/hssf/record/SubRecord.java
@@ -18,6 +18,7 @@
 package org.apache.poi.hssf.record;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.function.Supplier;
@@ -64,8 +65,8 @@ public abstract class SubRecord implements Duplicatable, GenericRecord {
             T apply(LittleEndianInput in, int size, int cmoOt);
         }
 
-        private static final Map<Short,SubRecordTypes> LOOKUP =
-            Arrays.stream(values()).collect(Collectors.toMap(SubRecordTypes::getSid, Function.identity()));
+        private static final Map<Short,SubRecordTypes> LOOKUP = Collections.unmodifiableMap(
+            Arrays.stream(values()).collect(Collectors.toMap(SubRecordTypes::getSid, Function.identity())));
 
         public final short sid;
         public final RecordConstructor<?> recordConstructor;
diff --git a/poi/src/main/java/org/apache/poi/ss/usermodel/FormulaError.java b/poi/src/main/java/org/apache/poi/ss/usermodel/FormulaError.java
index 5ffdd6e47e..785bfa6905 100644
--- a/poi/src/main/java/org/apache/poi/ss/usermodel/FormulaError.java
+++ b/poi/src/main/java/org/apache/poi/ss/usermodel/FormulaError.java
@@ -16,6 +16,7 @@
 ==================================================================== */
 package org.apache.poi.ss.usermodel;
 
+import java.util.Collections;
 import java.util.Map;
 
 import org.apache.poi.util.Internal;
@@ -149,15 +150,21 @@ public enum FormulaError {
         return repr;
     }
 
-    private static final Map<String, FormulaError> smap = new HashMap<>();
-    private static final Map<Byte, FormulaError> bmap = new HashMap<>();
-    private static final Map<Integer, FormulaError> imap = new HashMap<>();
-    static{
+    private static final Map<String, FormulaError> smap;
+    private static final Map<Byte, FormulaError> bmap;
+    private static final Map<Integer, FormulaError> imap;
+    static {
+        final Map<String, FormulaError> mapS = new HashMap<>();
+        final Map<Byte, FormulaError> mapB = new HashMap<>();
+        final Map<Integer, FormulaError> mapI = new HashMap<>();
         for (FormulaError error : values()) {
-            bmap.put(error.getCode(), error);
-            imap.put(error.getLongCode(), error);
-            smap.put(error.getString(), error);
+            mapB.put(error.getCode(), error);
+            mapI.put(error.getLongCode(), error);
+            mapS.put(error.getString(), error);
         }
+        smap = Collections.unmodifiableMap(mapS);
+        bmap = Collections.unmodifiableMap(mapB);
+        imap = Collections.unmodifiableMap(mapI);
     }
 
     public static boolean isValidCode(int errorCode) {
diff --git a/poi/src/main/java/org/apache/poi/ss/usermodel/PageMargin.java b/poi/src/main/java/org/apache/poi/ss/usermodel/PageMargin.java
index 34c732c32f..907886a97d 100644
--- a/poi/src/main/java/org/apache/poi/ss/usermodel/PageMargin.java
+++ b/poi/src/main/java/org/apache/poi/ss/usermodel/PageMargin.java
@@ -16,6 +16,7 @@
 ==================================================================== */
 package org.apache.poi.ss.usermodel;
 
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -75,11 +76,11 @@ public enum PageMargin {
     private static final Map<Short, PageMargin> PAGE_MARGIN_BY_LEGACY_API_VALUE;
 
     static {
-        PAGE_MARGIN_BY_LEGACY_API_VALUE = new HashMap<>();
-
+        final Map<Short, PageMargin> map = new HashMap<>();
         for (PageMargin margin : values()) {
-            PAGE_MARGIN_BY_LEGACY_API_VALUE.put(margin.legacyApiValue, margin);
+            map.put(margin.legacyApiValue, margin);
         }
+        PAGE_MARGIN_BY_LEGACY_API_VALUE = Collections.unmodifiableMap(map);
     }
 
     /**
diff --git a/poi/src/main/java/org/apache/poi/ss/util/CellUtil.java b/poi/src/main/java/org/apache/poi/ss/util/CellUtil.java
index 593dd6eef9..6d3ebb3678 100644
--- a/poi/src/main/java/org/apache/poi/ss/util/CellUtil.java
+++ b/poi/src/main/java/org/apache/poi/ss/util/CellUtil.java
@@ -265,31 +265,33 @@ public final class CellUtil {
     public static final String QUOTE_PREFIXED = "quotePrefixed";
 
     // FIXME Must be deleted along with string constants
-    static final Map<String, CellPropertyType> namePropertyMap = new HashMap<>();
+    static final Map<String, CellPropertyType> namePropertyMap;
 
     static {
-        namePropertyMap.put(ALIGNMENT, CellPropertyType.ALIGNMENT);
-        namePropertyMap.put(BORDER_BOTTOM, CellPropertyType.BORDER_BOTTOM);
-        namePropertyMap.put(BORDER_LEFT, CellPropertyType.BORDER_LEFT);
-        namePropertyMap.put(BORDER_RIGHT, CellPropertyType.BORDER_RIGHT);
-        namePropertyMap.put(BORDER_TOP, CellPropertyType.BORDER_TOP);
-        namePropertyMap.put(BOTTOM_BORDER_COLOR, CellPropertyType.BOTTOM_BORDER_COLOR);
-        namePropertyMap.put(LEFT_BORDER_COLOR, CellPropertyType.LEFT_BORDER_COLOR);
-        namePropertyMap.put(RIGHT_BORDER_COLOR, CellPropertyType.RIGHT_BORDER_COLOR);
-        namePropertyMap.put(TOP_BORDER_COLOR, CellPropertyType.TOP_BORDER_COLOR);
-        namePropertyMap.put(FILL_BACKGROUND_COLOR, CellPropertyType.FILL_BACKGROUND_COLOR);
-        namePropertyMap.put(FILL_FOREGROUND_COLOR, CellPropertyType.FILL_FOREGROUND_COLOR);
-        namePropertyMap.put(FILL_BACKGROUND_COLOR_COLOR, CellPropertyType.FILL_BACKGROUND_COLOR_COLOR);
-        namePropertyMap.put(FILL_FOREGROUND_COLOR_COLOR, CellPropertyType.FILL_FOREGROUND_COLOR_COLOR);
-        namePropertyMap.put(FILL_PATTERN, CellPropertyType.FILL_PATTERN);
-        namePropertyMap.put(FONT, CellPropertyType.FONT);
-        namePropertyMap.put(HIDDEN, CellPropertyType.HIDDEN);
-        namePropertyMap.put(INDENTION, CellPropertyType.INDENTION);
-        namePropertyMap.put(LOCKED, CellPropertyType.LOCKED);
-        namePropertyMap.put(ROTATION, CellPropertyType.ROTATION);
-        namePropertyMap.put(VERTICAL_ALIGNMENT, CellPropertyType.VERTICAL_ALIGNMENT);
-        namePropertyMap.put(SHRINK_TO_FIT, CellPropertyType.SHRINK_TO_FIT);
-        namePropertyMap.put(QUOTE_PREFIXED, CellPropertyType.QUOTE_PREFIXED);
+        final Map<String, CellPropertyType> map = new HashMap<>();
+        map.put(ALIGNMENT, CellPropertyType.ALIGNMENT);
+        map.put(BORDER_BOTTOM, CellPropertyType.BORDER_BOTTOM);
+        map.put(BORDER_LEFT, CellPropertyType.BORDER_LEFT);
+        map.put(BORDER_RIGHT, CellPropertyType.BORDER_RIGHT);
+        map.put(BORDER_TOP, CellPropertyType.BORDER_TOP);
+        map.put(BOTTOM_BORDER_COLOR, CellPropertyType.BOTTOM_BORDER_COLOR);
+        map.put(LEFT_BORDER_COLOR, CellPropertyType.LEFT_BORDER_COLOR);
+        map.put(RIGHT_BORDER_COLOR, CellPropertyType.RIGHT_BORDER_COLOR);
+        map.put(TOP_BORDER_COLOR, CellPropertyType.TOP_BORDER_COLOR);
+        map.put(FILL_BACKGROUND_COLOR, CellPropertyType.FILL_BACKGROUND_COLOR);
+        map.put(FILL_FOREGROUND_COLOR, CellPropertyType.FILL_FOREGROUND_COLOR);
+        map.put(FILL_BACKGROUND_COLOR_COLOR, CellPropertyType.FILL_BACKGROUND_COLOR_COLOR);
+        map.put(FILL_FOREGROUND_COLOR_COLOR, CellPropertyType.FILL_FOREGROUND_COLOR_COLOR);
+        map.put(FILL_PATTERN, CellPropertyType.FILL_PATTERN);
+        map.put(FONT, CellPropertyType.FONT);
+        map.put(HIDDEN, CellPropertyType.HIDDEN);
+        map.put(INDENTION, CellPropertyType.INDENTION);
+        map.put(LOCKED, CellPropertyType.LOCKED);
+        map.put(ROTATION, CellPropertyType.ROTATION);
+        map.put(VERTICAL_ALIGNMENT, CellPropertyType.VERTICAL_ALIGNMENT);
+        map.put(SHRINK_TO_FIT, CellPropertyType.SHRINK_TO_FIT);
+        map.put(QUOTE_PREFIXED, CellPropertyType.QUOTE_PREFIXED);
+        namePropertyMap = Collections.unmodifiableMap(map);
     }
 
     private static final UnicodeMapping[] unicodeMappings;
diff --git a/poi/src/main/java/org/apache/poi/util/LocaleID.java b/poi/src/main/java/org/apache/poi/util/LocaleID.java
index 6438adf535..9b843e05ed 100644
--- a/poi/src/main/java/org/apache/poi/util/LocaleID.java
+++ b/poi/src/main/java/org/apache/poi/util/LocaleID.java
@@ -21,6 +21,7 @@ import static java.util.Calendar.SATURDAY;
 import static java.util.Calendar.SUNDAY;
 
 import java.util.Calendar;
+import java.util.Collections;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Collectors;
@@ -508,11 +509,12 @@ public enum LocaleID {
     private final int defaultCodepage;
     private final int firstWeekday;
 
-    private static final Map<String, LocaleID> languageTagLookup =
-        Stream.of(values()).filter(LocaleID::isValid).collect(Collectors.toMap(LocaleID::getLanguageTag, Function.identity()));
+    private static final Map<String, LocaleID> languageTagLookup = Collections.unmodifiableMap(
+        Stream.of(values()).filter(LocaleID::isValid)
+            .collect(Collectors.toMap(LocaleID::getLanguageTag, Function.identity())));
 
-    private static final Map<Integer, LocaleID> lcidLookup =
-        Stream.of(values()).collect(Collectors.toMap(LocaleID::getLcid, Function.identity()));
+    private static final Map<Integer, LocaleID> lcidLookup = Collections.unmodifiableMap(
+        Stream.of(values()).collect(Collectors.toMap(LocaleID::getLcid, Function.identity())));
 
     LocaleID(int lcid, String windowsId, String languageTag, String description, int defaultCodepage, int firstWeekday) {
         this.lcid = lcid;