Implement toString() for HttpProtocolConfig and its components

[idelpivnitskiy]

Motivation:

For easier debugging and visibility of the internal state of the
HttpProtocolConfig implementations and its subcomponents.

Modifications:

• Implement toString() for DefaultH1ProtocolConfig,
  DefaultH2ProtocolConfig, DefaultHttpHeadersFactory,
  H2HeadersFactory, DefaultKeepAlivePolicy, H1SpecExceptions;

Result:

Users can log intercepted configurations to see what is inside.

[bondolo]

I usually use this.getClass().getSimpleName() so that the result is correct even for sub-classes that do not override. For final classes I end up using the same pattern for consistency and so that I don't have to change it if the class is refactored, becomes non-final, etc.

[idelpivnitskiy]

Sounds good, I've adjusted my Intellij IDEA template for generating toString() methods:

public java.lang.String toString() {
#if ( $members.size() > 0 )
#set ( $i = 0 )
    return getClass().getSimpleName() +
#foreach( $member in $members )
#if ( $i == 0 )
    "{##
#else
    ", ##
#end
#if ( $member.objectArray )
#if ($java_version < 5)
$member.name=" + ($member.accessor == null ? null : java.util.Arrays.asList($member.accessor)) +
#else
$member.name=" + java.util.Arrays.toString($member.accessor) +
#end
#elseif ( $member.primitiveArray && $java_version >= 5)
$member.name=" + java.util.Arrays.toString($member.accessor) +
#elseif ( $member.string )
$member.name='" + $member.accessor + '\'' +
#else
$member.name=" + $member.accessor +
#end
#set ( $i = $i + 1 )
#end
    '}';
#else
    return getClass().getSimpleName() + "{}";
#end
}