Merge pull request nextgenhealthcare#4 from tonygermano/safe_get

Added code template for Thread-safe get or create from globalMap

Author: narupley

Code Templates/Thread-safe get or create from globalMap/LICENSE

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+This Source Code Form is subject to the terms of the Mozilla Public
+License, v. 2.0. If a copy of the MPL was not distributed with this
+file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Files in this subfolder are Copyright Tony Germano 2019.

Code Templates/Thread-safe get or create from globalMap/README.md

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+# Thread-safe get or create from globalMap
+For a given key, retrieve the value from the globalMap. If the globalMap does not contain the key or the object returned is null produce and store a new object in a thread-safe manner.
+
+### Parameters:
+
+- **globalMapkey:** Key under which this object is stored in the globalMap. Also used as the key for the synchronization object in the globalMap.
+- **initializer:** Function which will be called when the value for globalMapKey is null. Returns the object to be stored as the value for globalMapKey.
+
+### Examples
+Get synchronized SortedSet stored in the globalMap with key `mySet` or create it if it doesn't exist.
+
+```javascript
+with (JavaImporter(java.util)) {
+    var mySet = getInstance('mySet', function() {
+        return Collections.synchronizedSortedSet(new TreeSet());
+    });
+}
+```

Code Templates/Thread-safe get or create from globalMap/Thread-safe get or create from globalMap.js

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+/**
+    For a given key, retrieve the value from the globalMap. If the globalMap does not contain the key or
+    the object returned is null produce and store a new object in a thread-safe manner.
+
+    @param {string} globalMapKey - Key under which this object is stored in the globalMap. Also used
+        as the key for the synchronization object in the globalMap.
+    @param {function():any} initializer - Function which will be called when the value for
+        globalMapKey is null. Returns the object to be stored as the value for globalMapKey.
+    @return {any} Object previously stored by globalMapKey or object created by initializer.
+
+    @author Tony Germano
+*/
+function getInstance(globalMapKey, initializer) {
+    var val = globalMap.get(globalMapKey);
+    if (val == null)  {
+        if (!globalMap.containsKeySync(globalMapKey)) {
+            globalMap.putSync(globalMapKey,null);
+        }
+        try {
+            globalMap.lock(globalMapKey);
+            if ((val = globalMap.get(globalMapKey)) == null) {
+                val = initializer();
+                globalMap.put(globalMapKey, val);
+            }
+        }
+        finally {
+            globalMap.unlock(globalMapKey);
+        }
+    }
+    return val;
+};

Code Templates/Thread-safe get or create from globalMap/Thread-safe get or create from globalMap.xml

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+<codeTemplate version="3.5.1">
+  <id>d9c5b969-56ad-4a2f-bcec-e6708deea959</id>
+  <name>getInstance</name>
+  <revision>7</revision>
+  <lastModified>
+    <time>1571360939576</time>
+    <timezone>GMT</timezone>
+  </lastModified>
+  <contextSet>
+    <delegate>
+      <contextType>DESTINATION_DISPATCHER</contextType>
+      <contextType>DESTINATION_FILTER_TRANSFORMER</contextType>
+      <contextType>DESTINATION_RESPONSE_TRANSFORMER</contextType>
+      <contextType>SOURCE_RECEIVER</contextType>
+      <contextType>SOURCE_FILTER_TRANSFORMER</contextType>
+    </delegate>
+  </contextSet>
+  <properties class="com.mirth.connect.model.codetemplates.BasicCodeTemplateProperties">
+    <type>FUNCTION</type>
+    <code>/**
+    For a given key, retrieve the value from the globalMap. If the globalMap does not contain the key or
+    the object returned is null produce and store a new object in a thread-safe manner.
+
+    @param {string} globalMapKey - Key under which this object is stored in the globalMap. Also used
+        as the key for the synchronization object in the globalMap.
+    @param {function():any} initializer - Function which will be called when the value for
+        globalMapKey is null. Returns the object to be stored as the value for globalMapKey.
+    @return {any} Object previously stored by globalMapKey or object created by initializer.
+
+    @author Tony Germano
+*/
+function getInstance(globalMapKey, initializer) {
+    var val = globalMap.get(globalMapKey);
+    if (val == null)  {
+        if (!globalMap.containsKeySync(globalMapKey)) {
+            globalMap.putSync(globalMapKey,null);
+        }
+        try {
+            globalMap.lock(globalMapKey);
+            if ((val = globalMap.get(globalMapKey)) == null) {
+                val = initializer();
+                globalMap.put(globalMapKey, val);
+            }
+        }
+        finally {
+            globalMap.unlock(globalMapKey);
+        }
+    }
+    return val;
+};
+</code>
+  </properties>
+</codeTemplate>

README.md

@@ -21,6 +21,7 @@ This is a repository of example channels, code templates, and other scripts you
  - Replace in All Descendant XML Nodes
  - Run on Startup
  - Strip Empty Nodes from XML
+ - Thread-safe get or create from globalMap
  - Unescape `\Xdd..\` HL7 Sequences
 
 #### Scripts