There were few of those - as while the alliance with Germany had been generally well received, that with Austria-Hungary, the old enemy of the Italian Independence Wars, was taken by large portions of the public opinion as an (unpleasant) necessity; and after the death of Crispi (1901), who had genuinely hoped to turn the Triple Alliance into an offensive instrument for his anti-French policy, the Italian establishment understood the Alliance as a defensive instrument where the idea of mutual defense was as important as that of keeping an eye on the Austrian expansion in the Balkans.

This was one of the reasons behind the Italian choice to initiate hostilities against the Ottomans in 1911-12 after the Austrians had arguably broken such equilibrium with the annexation of Bosnia-Herzegovina in 1908.

Therefore most of the political and economical forces which aimed at keeping the Triple in vigor, did so with the purpose of avoiding a general conflict, rather than running into it.

For those who wanted war, Austria was the natural enemy, both in terms of possible material gains (despite the objective difficulties that the Alpine front entailed - but similar or even worse difficulties existed on the French front) and in so far as there was already a tradition of anti-Austrian sentiment to be exploited in order to make some pro-war noise.

Here again, one should not overestimate the influence of irredentism in the matter of Italian interventions - as it was "politically irrelevant" by the 1910s according to the Italian foreign ministry A. di San Giuliano. Other forces nonetheless - those who looked for a modernization and "democraticization" of the Italian system - similarly looked at the French and British models rather than at the German and Austrian one.

This was certainly true of the Italian socialist interventionists (who sided with the French almost immediately and had traditionally close relations with them), fringe groups like the Futurists that played some role in creating the tone of the interventionist propaganda, the forces of the liberal interventionism (men like the Chief Editor of the Corriere della Sera Luigi Albertini who looked at the British liberal conservatism as an ideal model for the Italian society).

This leaves us with two groups which were open to an intervention with Germany and Austria: the military and the nationalists.

For the military it was in substance a matter of following the pre-existing plan. The Triple had been in action under various forms since the Tunis crisis of 1882 and most of the Italian High Command had formed on and studied its possible strategical developments.

It is to be noted that Italy had no real plans for an offensive development of a conflict with France or Austria - as both wars would have seen Italy as the smaller power forced on the defensive. The idea of engaging the French offensively on the alpine front was especially considered impossible. Therefore the Triple called for the transfer of five (later reduced to three) Italian Army Corps to the Rhineland front to be placed under German command and for the rest of the Italian army to hold ground on the French border.

This strategic view had been approved and confirmed - despite the chances of a war with France dropping considerably when Boulanger first and Crispi then fell out of political favor - by Chief of Staff Alberto Pollio in 1908. Pollio died though on July 2^nd 1914 and was replaced by Luigi Cadorna - less favorable to the Triple - who nonetheless advised the Prime Minister (then Antonio Salandra) for an immediate mobilization and preparations for the expedition to the Rhineland. Cadorna kept planning for an intervention on the Triple Alliance side; partly because he was kept in the dark of the diplomatic evolution, and partly because the Army hierarchy implicitly expected the Italian government to honor its committment.

Even then, there was little to no resistance when the choice was made in favor of the Entente - the Italian Military had its own Risorgimento tradition and while somewhat faovrable to the Germans it wasn't going to complain too much over a War with Austria. It is telling nonetheless that Italy only declared war on Germany in August 1916 - for both a matter of diplomatic form and general reluctance to a complete turn on the former ally.

As for the nationalists, the situation there becomes more confuse. With the Libyan War the Italian nationalists - formed into a proper political organization (the Italian Nationalist Association) just in time for the war - had made of direct expansion within the Mediterranean Sea one of the immediate national needs and a key element of their political platform. It was apparent that the best chance of this expansion went towards the Balkans, the Adriatic Coast, Greek islands, portions of the Turkish lands.

Nonetheless the Nationalists also had placed their accent on a strong internal organization, principles of authority and internal hierarchy - not only that, but prominent members of the Nationalist Association like future fascist ministry Alfredo Rocco had been directly influenced by German thought (for instance in the matter of public right, with Rocco supporting the juridical doctrine of the state) and had openly rejected and denounced the democratic principles and parliamentarism as a "British import".

Their first steps were therefore rather unsure, with some advocating for war with Germany and other calling for war against Austria - it soon became clear to them though, that it was going to be either war with France and GB or neutrality; and, since the Nationalists could not accept the idea that Italy would sit out the war that was going to define the new century, they fell in line with the Entente, despite their persisting sympathies for the German model of social and political organization (Rocco curiously enough would continue to take the War as evidence of the weakness of the democratic principle even in the 1920s - since the Entente powers in his view had only achieved victory once they had renounced it and moved onto authoritarian forms of social organization).

If you are interested I can look up a few of the immediate reactions to the war declaration - but it's fair to say that the vast majority of the Italian public opinion and establishment were almost immediately against the idea of an intervention on the side of the Triple Alliance. Following events such as the "rape of Belgium" did very little to increase the Central Powers' popularity.

You can find more details in works such as P. Melograni's Storia politica della Grande Guerra and F. Gaeta's Il nazionalismo italiano - I don't have much in terms of English language sources though. But the matter of the Italian intervention gets a cursory treatment in most works on the early stages of WW1.