protobuf/ruby/src/main/java/com/google/protobuf/jruby/RubyEnum.java

/*
 * Protocol Buffers - Google's data interchange format
 * Copyright 2014 Google Inc.  All rights reserved.
 * https://developers.google.com/protocol-buffers/
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.google.protobuf.jruby;

import com.google.protobuf.Descriptors;
import org.jruby.RubyModule;
import org.jruby.RubyNumeric;
import org.jruby.anno.JRubyMethod;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;

public class RubyEnum {
    /*
     * call-seq:
     *     Enum.lookup(number) => name
     *
     * This module method, provided on each generated enum module, looks up an enum
     * value by number and returns its name as a Ruby symbol, or nil if not found.
     */
    @JRubyMethod(meta = true)
    public static IRubyObject lookup(ThreadContext context, IRubyObject recv, IRubyObject number) {
        RubyEnumDescriptor rubyEnumDescriptorescriptor = (RubyEnumDescriptor) getDescriptor(context, recv);
        Descriptors.EnumDescriptor descriptor = rubyEnumDescriptorescriptor.getDescriptor();
        Descriptors.EnumValueDescriptor value = descriptor.findValueByNumber(RubyNumeric.num2int(number));
        if (value == null) return context.runtime.getNil();
        return context.runtime.newSymbol(value.getName());
    }

    /*
     * call-seq:
     *     Enum.resolve(name) => number
     *
     * This module method, provided on each generated enum module, looks up an enum
     * value by name (as a Ruby symbol) and returns its name, or nil if not found.
     */
    @JRubyMethod(meta = true)
    public static IRubyObject resolve(ThreadContext context, IRubyObject recv, IRubyObject name) {
        RubyEnumDescriptor rubyEnumDescriptorescriptor = (RubyEnumDescriptor) getDescriptor(context, recv);
        Descriptors.EnumDescriptor descriptor = rubyEnumDescriptorescriptor.getDescriptor();
        Descriptors.EnumValueDescriptor value = descriptor.findValueByName(name.asJavaString());
        if (value == null) return context.runtime.getNil();
        return context.runtime.newFixnum(value.getNumber());
    }

    /*
     * call-seq:
     *     Enum.descriptor
     *
     * This module method, provided on each generated enum module, returns the
     * EnumDescriptor corresponding to this enum type.
     */
    @JRubyMethod(meta = true, name = "descriptor")
    public static IRubyObject getDescriptor(ThreadContext context, IRubyObject recv) {
        return ((RubyModule) recv).getInstanceVariable(Utils.DESCRIPTOR_INSTANCE_VAR);
    }
}