map-builder-java

Fluent builder for Maps in Java.

Easily initialize (as expressions) or modify java.util.Map instances with a DRY, fluent-style builder pattern. No more repeated variable names, static or instance initializer blocks, or double brace initialization. At least until Java 9's Map.of, and Map.ofEntries with Map.entry.

Use

Build a new map (HashMap by default):

import me.andrz.builder.map.MapBuilder;

// ...

Map<String, Integer> m = new MapBuilder<String, Integer>()
  .put( k1, v1 )
  .p( k2, v2 )
  .putAll( otherMap )
  .pa( otherMap2 )
  .put( mapEntry )
  .p( mapEntry2 )
  .remove( k2 )
  // ...
  .build();

Or, choose a Map implementation by passing its class:

Map<String, Integer> m = new MapBuilder<String, Integer>(LinkedHashMap.class)
  // ...
  .build();

Or, pass an existing map to be modified. This also allows choice of Map implementation:

Map<String, Integer> m = new MapBuilder<String, Integer>(new LinkedHashMap<String, Integer>())
  // ...
  .build();

Install

Maven

<dependencies>
    <dependency>
        <groupId>me.andrz</groupId>
        <artifactId>map-builder</artifactId>
        <version>1.0.0</version>
    </dependency>
</dependencies>

Gradle

repositories {
    mavenCentral()
}

dependencies {
    compile 'me.andrz:map-builder:1.0.0'
}

Manual

Download JAR from Maven Central.

References

• Apache Commons Collections MapUtils#putAll
• Guava ImmutableMap.Builder
• http://minborgsjavapot.blogspot.com/2014/12/java-8-initializing-maps-in-smartest-way.html
• https://docs.atlassian.com/jira/6.4.1/com/atlassian/jira/util/collect/MapBuilder.html
• http://stackoverflow.com/a/8879328/851135
• http://stackoverflow.com/a/7345751/851135
• http://stackoverflow.com/a/12228431
• Initialize with list of Objects: https://gist.github.com/shunirr/4577191
• Fluent API for Maps: https://gist.github.com/eeichinger/4442854
• https://code.google.com/p/fluentjava/wiki/GettingStarted#Maps