One of the basic principles for implementing the FreeMarker engine is that the data model can only be accessed in read-only mode.
A value from a data model cannot be changed during template execution.
One of the consequences concerns the Hash type: FreeMarker can be used to create a Hash object literally but, once it is created, the object cannot be changed (click here for more details).
Example:
<#assign hashVal = {"attr1": "val1","attr2": "val2","attr3": "val3"} /><#list hashVal as aKey, aVal>...</#list>${hashVal["attr2"]}<#-- It is possible to browse the hashVal values or access a hashVal attribute value but it is not easy to change a hashVal attribute value or add/delete an attribute --><#-- Inefficient solution for changing an attribute value --><#assign attrModified = "attr2" /><#assign hashVal = hashVal + { attrModified : "val2Modified" }/><#-- Inefficient solution for deleting an attribute --><#assign hashVal = {"attr1": "val1","attr2": "val2","attr3": "val3"} /><#assign attrToDelete = "attr2" , tmpHash = {} /><#list hashVal as key, val><#if key != attrToDelete><#assign tmpHash = tmpHash + {key: val} /></#if></#list><#assign hashVal = tmpHash />
This function returns a Hash-type object with basic add, change and delete methods. It can take an argument:
- Either no parameter: the returned Hash object is empty,
- Or a Hash object: the returned Hash object is a copy. These attributes/values are identical to the Hash object passed as a parameter,
- a String-type key and a value of any type: the returned Hash type will contain a single attribute, the name of which is the value of the key passed as a parameter and the associated value of which is that passed as a parameter.
Parameters
Hash |
originalHash |
The returned Hash object contains the originalHash attribute/value pairs. |
Optional |
All types |
value |
Attribute value called "key" in the returned object |
Optional. Mandatory if the first parameter is String type |
For example
<#-- Create empty hash --><#assign newHash = hardisCore.createSimpleHash() />Size of newHash:${newSeq?keys?size}<#-- Create Hash from another Hash --><#assign originalHash = {"attr1": 1, "attr2":true} /><#assign newHash = hardisCore.createSimpleHash(originalHash) />Size of newHash:${newSeq?keys?size}<#-- Create Hash with one sub variable --><#assign newHash = hardisCore.createSimpleHash("myKey", "myValue") />Size of newHash:${newSeq?keys?size}