versioned_dependency_component.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 'fileutils'
require 'java_buildpack/component'
require 'java_buildpack/component/base_component'
require 'java_buildpack/repository/configured_item'
require 'java_buildpack/util/dash_case'
require 'tmpdir'

module JavaBuildpack::Component

  # A convenience base class for all components that have a versioned dependency.  In addition to the functionality
  # inherited from +BaseComponent+ this class also ensures that managed dependencies are handled in a uniform manner.
  class VersionedDependencyComponent < BaseComponent

    # Creates an instance.  In addition to the functionality inherited from +BaseComponent+, +@version+ and +@uri+
    # instance variables are exposed.
    def initialize(context, &version_validator)
      super(context)

      if supports?
        @version, @uri = JavaBuildpack::Repository::ConfiguredItem.find_item(@component_name, @configuration,
                                                                             &version_validator)
      else
        @version = nil
        @uri     = nil
      end
    end

    # If the component should be used when staging an application
    #
    # @return [Array<String>, String, nil] If the component should be used when staging the application, a +String+ or
    #                                      an +Array<String>+ that uniquely identifies the component (e.g.
    #                                      +openjdk=1.7.0_40+).  Otherwise, +nil+.
    def detect
      @version ? id(@version) : nil
    end

    protected

    # Whether or not this component supports this application
    #
    # @return [Boolean] whether or not this component supports this application
    def supports?
      fail "Method 'supports?' must be defined"
    end

    # Downloads a given JAR file and stores it.
    #
    # @param [String] jar_name the name to save the jar as
    # @param [Pathname] target_directory the directory to store the JAR file in.  Defaults to the component's sandbox.
    # @param [String] name an optional name for the download.  Defaults to +@component_name+.
    def download_jar(jar_name = jar_name, target_directory = @droplet.sandbox, name = @component_name)
      super(@version, @uri, jar_name, target_directory, name)
    end

    # Downloads a given TAR file and expands it.
    #
    # @param [Pathname] target_directory the directory to expand the TAR file to.  Defaults to the component's sandbox.
    # @param [String] name an optional name for the download and expansion.  Defaults to +@component_name+.
    def download_tar(target_directory = @droplet.sandbox, name = @component_name)
      super(@version, @uri, target_directory, name)
    end

    # Downloads a given ZIP file and expands it.
    #
    # @param [Boolean] strip_top_level whether to strip the top-level directory when expanding. Defaults to +true+.
    # @param [Pathname] target_directory the directory to expand the ZIP file to.  Defaults to the component's sandbox.
    # @param [String] name an optional name for the download.  Defaults to +@component_name+.
    def download_zip(strip_top_level = true, target_directory = @droplet.sandbox, name = @component_name)
      super(@version, @uri, strip_top_level, target_directory, name)
    end

    # A generated JAR name for the component.  Meets the format +<component-id>-<version>.jar+
    def jar_name
      "#{@droplet.component_id}-#{@version}.jar"
    end

    private

    def id(version)
      "#{self.class.to_s.dash_case}=#{version}"
    end

  end

end