java_opts.rb

# Encoding: utf-8
# Cloud Foundry Java Buildpack
# Copyright 2013 the original author or authors.
#
# 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.

require 'java_buildpack/framework'
require 'shellwords'

module JavaBuildpack::Framework

  # Encapsulates the detect, compile, and release functionality for contributing custom Java options to an application
  # at runtime.
  class JavaOpts

    # Creates an instance, passing in an arbitrary collection of options.
    #
    # @param [Hash] context the context that is provided to the instance
    # @option context [Array<String>] :java_opts an array that Java options can be added to
    # @option context [Hash] :configuration the properties provided by the user
    def initialize(context = {})
      context.each { |key, value| instance_variable_set("@#{key}", value) }
    end

    # Detects whether this application contributes Java options.
    #
    # @return [String] returns +java-opts+ if Java options have been set by the user
    def detect
      @configuration.key?(CONFIGURATION_PROPERTY) ? CONTAINER_NAME : nil
    end

    # Ensures that none of the Java options specify memory configurations
    #
    # @return [void]
    def compile
      parsed_java_opts.each do |option|
        raise "Java option '#{option}' configures a memory region.  Use JRE configuration for this instead." if memory_option? option
      end
    end

    # Adds the contents of +java.opts+ to the +context[:java_opts]+ for use when running the application
    #
    # @return [void]
    def release
      @java_opts.concat parsed_java_opts
    end

    private

    CONFIGURATION_PROPERTY = 'java_opts'.freeze

    CONTAINER_NAME = 'java-opts'.freeze

    def memory_option?(option)
      option =~ /-Xms/ || option =~ /-Xmx/ || option =~ /-XX:MaxMetaspaceSize/ || option =~ /-XX:MaxPermSize/ ||
          option =~ /-Xss/
    end

    def parsed_java_opts
      @configuration[CONFIGURATION_PROPERTY].shellsplit.map do |java_opt|
        java_opt.gsub(/([\s])/, '\\\\\1')
      end
    end

  end

end