[libpostgresql-jdbc-java] 07/11: Add some more synchronization to the TypeInfoCache. We need synchronization around the PreparedStatements because they may not be used by two threads at the same time. Additional synchronization is applied to the maps to ensure that they are in sync with each other. Make _pgNameToSQLType static.

[Emmanuel Bourg]

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ebourg-guest pushed a commit to tag REL8_1_406
in repository libpostgresql-jdbc-java.

commit 7ba14af0f1a9f62de6a9f9bd29599f14ac88a722
Author: Kris Jurka <books at ejurka.com>
Date:   Mon May 22 04:07:14 2006 +0000

    Add some more synchronization to the TypeInfoCache.  We need
    synchronization around the PreparedStatements because they may not
    be used by two threads at the same time.  Additional synchronization
    is applied to the maps to ensure that they are in sync with each
    other.  Make _pgNameToSQLType static.
    
    Till Toenges
---
 org/postgresql/jdbc2/TypeInfoCache.java | 49 +++++++++++++++++++++------------
 1 file changed, 32 insertions(+), 17 deletions(-)

diff --git a/org/postgresql/jdbc2/TypeInfoCache.java b/org/postgresql/jdbc2/TypeInfoCache.java
index f9c54e3..b6cc697 100644
--- a/org/postgresql/jdbc2/TypeInfoCache.java
+++ b/org/postgresql/jdbc2/TypeInfoCache.java
@@ -3,7 +3,7 @@
  * Copyright (c) 2005, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgjdbc/org/postgresql/jdbc2/TypeInfoCache.java,v 1.1 2005/04/10 21:54:16 jurka Exp $
+ *   $PostgreSQL: pgjdbc/org/postgresql/jdbc2/TypeInfoCache.java,v 1.1.2.1 2006/02/09 16:29:20 jurka Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -30,7 +30,7 @@ import org.postgresql.util.PSQLException;
 public class TypeInfoCache {
 
     // pgname (String) -> java.sql.Types (Integer)
-    private Map _pgNameToSQLType;
+    private static final Map _pgNameToSQLType;
 
     // pgname (String) -> java class name (String)
     // ie "text" -> "java.lang.String"
@@ -48,7 +48,7 @@ public class TypeInfoCache {
     private PreparedStatement _getOidStatement;
     private PreparedStatement _getNameStatement;
 
-    private static Object types[][] = {
+    private static final Object types[][] = {
         {"int2", new Integer(Oid.INT2), new Integer(Types.SMALLINT), "java.lang.Short"},
         {"int4", new Integer(Oid.INT4), new Integer(Types.INTEGER), "java.lang.Integer"},
         {"oid", new Integer(Oid.OID), new Integer(Types.INTEGER), "java.lang.Integer"},
@@ -71,28 +71,40 @@ public class TypeInfoCache {
         {"timestamptz", new Integer(Oid.TIMESTAMPTZ), new Integer(Types.TIMESTAMP), "java.sql.Timestamp"}
     };
 
+    static
+    {
+        Map pgNameToSQLType = new HashMap();
+        for (int i=0; i<types.length; i++) {
+            pgNameToSQLType.put(types[i][0], types[i][2]);
+            String arrayType = "_" + types[i][0];
+            pgNameToSQLType.put(arrayType, new Integer(Types.ARRAY));
+        }
+        // needs to be unmodifiable because the iterator is returned
+        // getPGTypeNamesWithSQLTypes() if the content of the map
+        // should ever need to be modified, this could be changed
+        // into a synchronizedMap()
+        _pgNameToSQLType = Collections.unmodifiableMap(pgNameToSQLType);
+    }
+
     public TypeInfoCache(BaseConnection conn)
     {
         _conn = conn;
-        _oidToPgName = Collections.synchronizedMap(new HashMap());
-        _pgNameToOid = Collections.synchronizedMap(new HashMap());
-        _pgNameToSQLType = Collections.synchronizedMap(new HashMap());
-        _pgNameToJavaClass = Collections.synchronizedMap(new HashMap());
-        _pgNameToPgObject = Collections.synchronizedMap(new HashMap());
+        _oidToPgName = new HashMap();
+        _pgNameToOid = new HashMap();
+        _pgNameToJavaClass = new HashMap();
+        _pgNameToPgObject = new HashMap();
 
         for (int i=0; i<types.length; i++) {
-            _pgNameToSQLType.put(types[i][0], types[i][2]);
             _pgNameToJavaClass.put(types[i][0], types[i][3]);
             _pgNameToOid.put(types[i][0], types[i][1]);
             _oidToPgName.put(types[i][1], types[i][0]);
             
             String arrayType = "_" + types[i][0];
-            _pgNameToSQLType.put(arrayType, new Integer(Types.ARRAY));
             _pgNameToJavaClass.put(arrayType, "java.sql.Array");
         }
     }
 
-    public void addDataType(String type, Class klass) throws SQLException
+    public synchronized void addDataType(String type, Class klass) throws SQLException
     {
         if (!PGobject.class.isAssignableFrom(klass))
             throw new PSQLException(GT.tr("The class {0} does not implement org.postgresql.util.PGobject.", klass.toString()), PSQLState.INVALID_PARAMETER_TYPE);
@@ -101,25 +113,28 @@ public class TypeInfoCache {
         _pgNameToJavaClass.put(type, klass.getName());
     }
 
-    public Iterator getPGTypeNamesWithSQLTypes()
+    public static Iterator getPGTypeNamesWithSQLTypes()
     {
+        // the map is unmodfiable
         return _pgNameToSQLType.keySet().iterator();
     }
 
+    // no need to synchronize because getSQLType uses an unmodfiable map
     public int getSQLType(int oid) throws SQLException
     {
         return getSQLType(getPGType(oid));
     }
 
-    public int getSQLType(String pgTypeName)
+    public static int getSQLType(String pgTypeName)
     {
+        // map is unmodifiable, no need to synchronize
         Integer i = (Integer)_pgNameToSQLType.get(pgTypeName);
         if (i != null)
             return i.intValue();
         return Types.OTHER;
     }
 
-    public int getPGType(String pgTypeName) throws SQLException
+    public synchronized int getPGType(String pgTypeName) throws SQLException
     {
         Integer oid = (Integer)_pgNameToOid.get(pgTypeName);
         if (oid != null)
@@ -152,7 +167,7 @@ public class TypeInfoCache {
         return oid.intValue();
     }
 
-    public String getPGType(int oid) throws SQLException
+    public synchronized String getPGType(int oid) throws SQLException
     {
         if (oid == Oid.INVALID)
             return null;
@@ -187,12 +202,12 @@ public class TypeInfoCache {
         return pgTypeName;
     }
 
-    public Class getPGobject(String type)
+    public synchronized Class getPGobject(String type)
     {
         return (Class)_pgNameToPgObject.get(type);
     }
 
-    public String getJavaClass(int oid) throws SQLException
+    public synchronized String getJavaClass(int oid) throws SQLException
     {
         String pgTypeName = getPGType(oid);
         return (String)_pgNameToJavaClass.get(pgTypeName);

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