value/src/main/java/com/google/auto/value/processor/builder.vm

## Copyright 2014 Google LLC
##
## Licensed under the Apache License, Version 2.0 (the "License");
## you may not use this file except in compliance with the License.
## You may obtain a copy of the License at
##
## http://www.apache.org/licenses/LICENSE-2.0
##
## Unless required by applicable law or agreed to in writing, software
## distributed under the License is distributed on an "AS IS" BASIS,
## WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
## See the License for the specific language governing permissions and
## limitations under the License.
##
##
##
## Template for AutoValue and AutoBuilder builders.
## This template uses the Apache Velocity Template Language (VTL).
## The variables ($isFinal, $props, and so on) are defined by the fields of AutoValueOrBuilderTemplateVars.
##
## Comments, like this one, begin with ##. The comment text extends up to and including the newline
## character at the end of the line. So comments also serve to join a line to the next one.
## Velocity deletes a newline after a directive (#if, #foreach, #end etc) so ## is not needed there.
## That does mean that we sometimes need an extra blank line after such a directive.
##
## Post-processing will remove unwanted spaces and blank lines, but will not join two lines.
## It will also replace classes spelled as (e.g.) `java.util.Arrays`, with the backquotes, to
## use just Arrays if that class can be imported unambiguously, or java.util.Arrays if not.
##
#foreach ($a in $builderAnnotations)
$a
#end
#if (!$autoBuilder) static #end##
#if ($isFinal) final #end##
class ${builderName}${builderFormalTypes} ##
#if ($builderIsInterface) implements #else extends #end
    ${builderTypeName}${builderActualTypes} {

#foreach ($p in $props)

  #if ($p.kind.primitive)

  private $types.boxedClass($p.typeMirror).simpleName $p;

  #else

    #if ($builderPropertyBuilders[$p.name])
    ## If you have ImmutableList.Builder<String> stringsBuilder() then we define two fields:
    ## private ImmutableList.Builder<String> stringsBuilder$;
    ## private ImmutableList<String> strings;

  private ${builderPropertyBuilders[$p.name].builderType} ##
      ${builderPropertyBuilders[$p.name].name};

    #end

  private $p.type $p #if ($p.optional && !$p.nullable) = $p.optional.empty #end ;

  #end
#end

  ${builderName}() {
  }

#if ($toBuilderConstructor)

  private ${builderName}(${origClass}${actualTypes} source) {

  #foreach ($p in $props)

    this.$p = source.${p.getter}();

  #end

  }

#end

#foreach ($p in $props)

  ## The following is either null or an instance of PropertyBuilderClassifier.PropertyBuilder
  #set ($propertyBuilder = $builderPropertyBuilders[$p.name])

  ## Setter and/or property builder

  #foreach ($setter in $builderSetters[$p.name])

  @`java.lang.Override`
  ${setter.access}${builderTypeName}${builderActualTypes} ##
      ${setter.name}(${setter.nullableAnnotation}$setter.parameterType $p) {

    ## Omit null check for primitive, or @Nullable, or if we are going to be calling a copy method
    ## such as Optional.of, which will have its own null check if appropriate.
    #if (!$setter.primitiveParameter && !$p.nullable && ${setter.copy($p)} == $p)

      #if ($identifiers)

    if ($p == null) {
      throw new NullPointerException("Null $p.name");
    }
      #else
        ## Just throw NullPointerException with no message if it's null.
        ## The Object cast has no effect on the code but silences an ErrorProne warning.

    ((`java.lang.Object`) ${p}).getClass();
      #end

    #end

    #if ($propertyBuilder)

    if (${propertyBuilder.name} != null) {
      throw new IllegalStateException(#if ($identifiers)"Cannot set $p after calling ${p.name}Builder()"#end);
    }

    #end

    this.$p = ${setter.copy($p)};
    return this;
  }

  #end

  #if ($propertyBuilder)

  @`java.lang.Override`
  ${propertyBuilder.access}$propertyBuilder.builderType ${p.name}Builder($propertyBuilder.propertyBuilderMethodParameters) {
    if (${propertyBuilder.name} == null) {

      ## This is the first time someone has asked for the builder. If the property it sets already
      ## has a value (because it came from a toBuilder() call on the AutoValue class, or because
      ## there is also a setter for this property) then we copy that value into the builder.
      ## Otherwise the builder starts out empty.
      ## If we have neither a setter nor a toBuilder() method, then the builder always starts
      ## off empty.

      #if ($builderSetters[$p.name].empty && $toBuilderMethods.empty)

      ${propertyBuilder.name} = ${propertyBuilder.initializer};

      #else

      if ($p == null) {
        ${propertyBuilder.name} = ${propertyBuilder.initializer};
      } else {

        #if (${propertyBuilder.builtToBuilder})

        ${propertyBuilder.name} = ${p}.${propertyBuilder.builtToBuilder}();

        #else

        ${propertyBuilder.name} = ${propertyBuilder.initializer};
        ${propertyBuilder.name}.${propertyBuilder.copyAll}($p);

        #end

        $p = null;
      }

      #end

    } #if (!$propertyBuilder.propertyBuilderMethodParameters.empty) else {
        ## This check only happens if the property-builder method has a parameter.
        ## We don't know if the existing builder was created with the same parameter,
        ## so we throw to avoid possibly giving you a builder that is different from
        ## the one you asked for.

      throw new IllegalStateException("Property builder for $p.name is already defined");
    }
      #end

    return $propertyBuilder.name;
  }

  #end

  ## Getter

  #if ($builderGetters[$p.name])

  @`java.lang.Override`
  ${p.nullableAnnotation}${builderGetters[$p.name].access}$builderGetters[$p.name].type ${p.getter}() {
    #if ($builderGetters[$p.name].optional)

    if ($p == null) {
      return $builderGetters[$p.name].optional.empty;
    } else {
      return ${builderGetters[$p.name].optional.rawType}.of($p);
    }

    #else
      #if ($builderRequiredProperties.contains($p))

    if ($p == null) {
      throw new IllegalStateException(#if ($identifiers)"Property \"$p.name\" has not been set"#end);
    }

      #end

      #if ($propertyBuilder)

    if (${propertyBuilder.name} != null) {
      return ${propertyBuilder.name}.build();
    }
    if ($p == null) {
      ${propertyBuilder.beforeInitDefault}
      $p = ${propertyBuilder.initDefault};
    }

      #end

    return $p;

    #end

  }

  #end
#end

## build() method

  @`java.lang.Override`
  ${buildMethod.get().access}${builtType} ${buildMethod.get().name}() ${buildMethod.get().throws} {

#foreach ($p in $props)
  #set ($propertyBuilder = $builderPropertyBuilders[$p.name])
  #if ($propertyBuilder)

    if (${propertyBuilder.name} != null) {
      this.$p = ${propertyBuilder.name}.build();
    } else if (this.$p == null) {
      ${propertyBuilder.beforeInitDefault}
      this.$p = ${propertyBuilder.initDefault};
    }

  #end
#end

#if (!$builderRequiredProperties.empty)
    if (#foreach ($p in $builderRequiredProperties)##
        this.$p == null##
          #if ($foreach.hasNext)

        || #end
        #end) {

  #if ($identifiers)  ## build a friendly message showing all missing properties
    #if ($builderRequiredProperties.size() == 1)

    `java.lang.String` missing = " $builderRequiredProperties.iterator().next()";

    #else

    `java.lang.StringBuilder` missing = new `java.lang.StringBuilder`();

      #foreach ($p in $builderRequiredProperties)

    if (this.$p == null) {
      missing.append(" $p.name");
    }

      #end
    #end

    throw new IllegalStateException("Missing required properties:" + missing);

  #else  ## just throw an exception if anything is missing

    throw new IllegalStateException();

  #end

  }

#end

    #if ($builtType != "void") return #end ${build}(
#foreach ($p in $props)

        this.$p #if ($foreach.hasNext) , #end
#end );
  }
}