templater

Java Library for template engine processing

Getting Started

• How to install this library?
• How to use this library?
• How to write templates?

How to install this library?

Currently, you have to retrieve source code from the GitHub repository and install the Java library locally thanks to Maven.

git clone https://github.com/JeromeRocheteau/templater.git
cd templater
mvn install

Once done, you need to insert the following dependency into your file pom.xml:

    <dependency>
      <groupId>com.github.jeromerocheteau</groupId>
      <artifactId>templater</artifactId>
      <version>1.0</version>
    </dependency>

How to use this library?

There are only 2 steps to follow in order to process templates i.e. it requires a template (file or string) and provides a string buffer that corresponds to the input template that has been fulfilled by some scope values:

1. create only once a Templater object by the means of its constructor in providing a Reader object build from an input source that corresponds to the template;
2. call as often as wanted the doProcess method in providing values to inject into the tempate map from strings to objects.

The following source code can help:

public class MyTemplater {

  private Templater templater;
	
  public void setUp(String path) throws Exception {
    InputStream stream = new FileInputStream(path);
    Reader reader = new InputStreamReader(stream);
    templater = new Templater(reader);
  }

  public void doTemplate(Map<String, Object> scope) throws Exception {
    StringBuffer buffer = templater.doProcess(scope);
    System.out.println(buffer.toString());
  }
  
}

How to write templates?

Templates are text files with special instructions defined by the pattern ${...}. Values can be injected into the template if they belong to the scope of the doProcess method. Scope elements can be either:

• values ${value},
• object fields ${object.field},
  • field paths can go through several objects ${object.innerObject.field};
• collections iterable according to a loop ${for item : collection} ... ${for},
  • use ${item-index} within a loop to get the index of the item in the iterared collection;
  • use ${item-first} within a loop to get a boolean value true if the item is the first of the collection;
  • use ${item-last} within a loop to get a boolean value true if the item is the last of the collection;
• maps iterable according to a loop ${for entry : map} ... ${for}.
  • use ${entry.key} within a loop to get the entry key of iterared map;
  • use ${entry.value} within a loop to get the entry value of iterared map;

Moreover, a test instruction ${if test} ... ${if} can be used in order to process the embedded template only if the testable value test is true. Testable values can be either:

• booleans: the test is true if and only if the boolean is true;
• objects: the test is true if and only if the object is not null;
• collections or maps: the test is true if and only if the object is not null and not empty;

There is no else instruction. Instead use the negation of a test ${if not test} .... ${if}.

The example below can help:

${task.name}

${if task.items}
  ${for item : task.items}
    ${item-index}. ${item}
    ${if item-last}.${if}
    ${if not item-last};${if}
  ${for}
${if}

Enjoy!